U.S. patent application number 13/886068 was filed with the patent office on 2014-02-13 for microfluidic and nanofluidic devices, systems, and applications.
This patent application is currently assigned to IntegenX Inc.. The applicant listed for this patent is luliu I. Balga, Allen R. Boronkay, Joanne Horn, Stevan Bogdan Jovanovich, William D. Nielsen, Michael Van Nguyen, Mattias Vangbo. Invention is credited to luliu I. Balga, Allen R. Boronkay, Joanne Horn, Stevan Bogdan Jovanovich, William D. Nielsen, Michael Van Nguyen, Mattias Vangbo.
Application Number | 20140045704 13/886068 |
Document ID | / |
Family ID | 39766690 |
Filed Date | 2014-02-13 |
United States Patent
Application |
20140045704 |
Kind Code |
A1 |
Jovanovich; Stevan Bogdan ;
et al. |
February 13, 2014 |
MICROFLUIDIC AND NANOFLUIDIC DEVICES, SYSTEMS, AND APPLICATIONS
Abstract
The present invention discloses the integration of programmable
microfluidic circuits to achieve practical applications to process
biochemical and chemical reactions and to integrate these
reactions. In some embodiments workflows for biochemical reactions
or chemical workflows are combined. Microvalves such as
programmable microfluidic circuit with Y valves and flow through
valves are disclosed. In some embodiments microvalves of the
present invention are used for mixing fluids, which may be part of
an integrated process. These processes include mixing samples and
moving reactions to an edge or reservoir for modular microfluidics,
use of capture regions, and injection into analytical devices on
separate devices. In some embodiments star and nested star designs,
or bead capture by change of cross sectional area of a channel in a
microvalve are used. Movement of samples between temperature zones
are further disclosed using fixed temperature and movement of the
samples by micropumps.
Inventors: |
Jovanovich; Stevan Bogdan;
(Livermore, CA) ; Balga; luliu I.; (Fremont,
CA) ; Boronkay; Allen R.; (San Jose, CA) ;
Horn; Joanne; (Oakland, CA) ; Van Nguyen;
Michael; (San Diego, CA) ; Nielsen; William D.;
(San Jose, CA) ; Vangbo; Mattias; (Fremont,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jovanovich; Stevan Bogdan
Balga; luliu I.
Boronkay; Allen R.
Horn; Joanne
Van Nguyen; Michael
Nielsen; William D.
Vangbo; Mattias |
Livermore
Fremont
San Jose
Oakland
San Diego
San Jose
Fremont |
CA
CA
CA
CA
CA
CA
CA |
US
US
US
US
US
US
US |
|
|
Assignee: |
IntegenX Inc.
Pleasanton
CA
|
Family ID: |
39766690 |
Appl. No.: |
13/886068 |
Filed: |
May 2, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12845650 |
Jul 28, 2010 |
8557518 |
|
|
13886068 |
|
|
|
|
12526015 |
Nov 3, 2010 |
|
|
|
PCT/US08/53099 |
Feb 5, 2008 |
|
|
|
12845650 |
|
|
|
|
60899630 |
Feb 5, 2007 |
|
|
|
Current U.S.
Class: |
506/2 ; 422/505;
422/69; 435/287.2; 435/6.12; 435/7.1; 436/501; 506/26; 506/38;
506/40 |
Current CPC
Class: |
B01L 2400/0481 20130101;
F16K 99/0001 20130101; B01L 2300/1827 20130101; B33Y 80/00
20141201; B01L 2200/10 20130101; B01L 7/52 20130101; B01L 2300/0887
20130101; C12Q 1/686 20130101; B01L 3/50273 20130101; B01L 7/525
20130101; B01L 2300/0874 20130101; B82Y 30/00 20130101; B01L
2400/0655 20130101; B01L 3/502761 20130101; B01L 2300/0816
20130101; B01L 3/502715 20130101; B01L 2300/0867 20130101; B01L
2200/0668 20130101; B01L 2300/088 20130101; B01L 2400/0622
20130101; B01L 3/502738 20130101; B01L 2200/028 20130101; B01L
2300/0896 20130101 |
Class at
Publication: |
506/2 ; 435/6.12;
435/7.1; 436/501; 506/26; 506/40; 506/38; 435/287.2; 422/69;
422/505 |
International
Class: |
C12Q 1/68 20060101
C12Q001/68; B01L 7/00 20060101 B01L007/00 |
Goverment Interests
STATEMENT AS TO FEDERALLY SPONSORED RESEARCH
[0002] Aspects of this invention were made with government support
under one or more of Project No. W911SR-04-P-0047 awarded by the
Department of Defense, Grant No. 5R01HG003583 awarded by the NIH,
Contract No. NBCHC050133 awarded by HSARPA, Order No. TTA-1-0014
(Agreement No. W81XWH-04-9-0012) awarded by HSARPA. The government
has certain rights in this invention.
Claims
1.-30. (canceled)
31. A system comprising: a first microfluidic device comprising: a
first microfluidic circuit comprising an inlet, an outlet, a pump
and at least one first functional component selected from a
reactor, a capture region, a temperature cycling zone, a hot zone,
a cool zone, separation channel, analysis circuit, mixer, bead
processing unit, and a magnet, wherein the pump is configured to
pump fluid through the circuit; and a second microfluidic device
comprising: a plurality of second microfluidic circuits, each
comprising an inlet, and outlet and at least one functional
component which is different than a first functional component;
wherein the first and second components are configured to engage in
a plurality of positions, wherein in each position the outlet of
the first circuit is mated with the inlet of one of the second
circuits to allow fluid to flow from the first circuit into the
mated second circuit.
32.-38. (canceled)
39. A method comprising: I) providing a system comprising: a first
microfluidic device comprising: a first microfluidic circuit
comprising an inlet, an outlet, a pump and at least one first
functional component selected from a reactor, a capture region, a
temperature cycling zone, a hot zone, a cool zone, separation
channel, analysis circuit, mixer, bead processing unit, and a
magnet, wherein the pump is configured to pump fluid through the
circuit; and a second microfluidic device comprising: a plurality
of second microfluidic circuits, each comprising an inlet, and
outlet and at least one functional component which is different
than a first functional component; wherein the first and second
components are configured to engage in a plurality of positions,
wherein in each position the outlet of the first circuit is mated
with the inlet of one of the second circuits to allow fluid to flow
from the first circuit into the mated second circuit; and II)
performing a method comprising: a) performing a first operation on
a first sample in a first microfluidic circuit of a first
microfluidic device comprising: a microfluidic layer, an actuation
layer and elastomer layer sandwiched between them, wherein: the
microfluidic layer comprises a microfluidic channel; the actuation
layer comprises at least one actuation channel opening into a valve
chamber, which valve chamber is disposed along the microfluidic
channel; and wherein fluid flows along the channel whether or not
the elastomeric membrane is displaced, but displacement of said
elastomeric membrane modulates fluid flow along said channel,
thereby forming a diaphragm valve; b) engaging the first and second
microfluidic devices of the system so that the output of the first
circuit is mated with the inlet of a first of the second
microfluidic circuits; c) moving first sample after the operation
from the first circuit into the first of the second circuits; d)
performing a second operation on the received first sample in the
first of the second circuits; e) performing the first operation on
a second sample in the first microfluidic circuit; f) engaging the
first and second microfluidic devices so that the output of the
first circuit is mated with the inlet of a next, different one of
the second microfluidic circuits; g) moving second sample after the
operation from the first circuit into the next of the second
circuits; and h) performing the second operation on the first
reacted sample in the first of the second circuits.
40.-42. (canceled)
43. A method of making a microfluidic device comprising: joining a
plurality of layers to form a plurality of microchannels and
diaphragm valves; wherein said plurality of layers are sandwiched
together; wherein said at least two layers of said plurality of
layers are selected from the group consisting of an elastomeric
membrane, an actuation layer, a microfluidic layer; a valve layer,
heat spreaders, a vias layer, an interface layer, and a cover
layer.
44.-49. (canceled)
50. A microfluidic device comprising: a) a microfluidic channel; b)
a first temperature zone disposed along the channel having a
temperature above ambient temperature; c) a second temperature zone
disposed along the channel having a temperature below ambient
temperature; and d) a positive displacement pump disposed along the
channel and configured to pump liquid into the first and second
temperature zones.
51.-62. (canceled)
63. A microfluidic device comprising: a microfluidic layer
comprising a microfluidic channel, wherein the channel comprises at
least one tight bend comprising two channel segments connected with
each other and oriented in an acute angle; and means for producing
a magnetic field that produces a magnetic field in the area of the
tight bend, wherein paramagnetic particles flowing through the
tight bend are retarded by the magnetic field.
64.-75. (canceled)
Description
CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/899,630 "Microfluidic and nanofluidic devices,
systems, and applications" filed Feb. 5, 2007, which application is
incorporated herein by reference, in its entirety.
BACKGROUND OF THE INVENTION
[0003] A variety of microfluidic devices of disparate, design have
been developed in the past often with the goal of reducing sample
volume requirements in bioanalytical methods, integrating multiple
steps into automated processes, integrating sample preparation and
analysis, and connecting to the full volume world of samples and
procedures.
[0004] In the absence of standards controlling external dimensional
form factors, the nature of the upstream and downstream external
interface, and the length, cross-sectional geometry, and diameter
of the internal microfluidic pathways, such microfluidic devices
often proved incompatible with one another and with existing
upstream purification and downstream analytical devices.
[0005] Despite advances in microfabrication, making possible
analysis at microliter, even nanoliter or picoliter, scale, many
biological and environmental samples are first acquired in volumes
far greater than, the scale of existing microfluidic analytical
devices.
[0006] Modular microfluidic technology can combine moving samples
on microchips. While a focus in microfluidics has been integration
of multiple functions onto a single device, the objects have been
achieved through an alternative approach that allows modular
integration of functions across multiple devices. This modular
concept is based on technologies, that allow arrays of capillaries
to be connected simply by plugging two connectors together (U.S.
Pat. No. 6,551,839; U.S. patent application Ser. No. 11/229,065;
U.S. Pat. No. 6,190,616; U.S. Pat. No. 6,423,536; U.S. patent
application Ser. No. 09/770,412; U.S. Pat. No. 6,870,185; U.S.
patent application Ser. No. 10/125,045; U.S. patent application
Ser. No. 10/540,658; U.S. patent application Ser. No. 10/750,533;
U.S. patent application Ser. No. 11/138,018; all of which are
herein incorporated by reference in their entirety). In addition to
creating connectors, the interface between the arrays also creates
true zero dead-volume valves and routers. The present disclosure
provides guidance on how to connect and disconnect microchips
containing fluidic circuits to other microchips or arrays of
capillaries, develops new microchip designs incorporating two,
three, or more microchips, provides new functionality, including
fraction collection, new applications, and instrumentation design.
This new technology is termed modular nanofluidics and the use of
microchips in modular nanofluidics is referred to as "modular
microfluidic microchips" or "modular microchips."
[0007] Modular microfluidic microchips have many applications in
the life sciences and medicine. Modular microchips create devices
can perform single functions or logically clustered groups of
functions. More complex processes are created by docking two
microdevices and transferring the processed samples. For example,
one microdevice might perform PCR amplification and cleanup of a
series of target DNAs, a second might perform cycle sequencing
reactions, and may connect to a third device that performs DNA
sequence analysis. Similarly, for proteomics, one device might
perform a first dimension of a separation and a second device a
second orthogonal separation. The ability to connect devices in a
"plug-and-play" manner permits processes with different rates,
cycle times, or throughputs to proceed independently. Sets of
modular microchips can be prepared and incubated in hotels. When
one step in a sample preparation process is complete, modular
microchips for the next step can be docked, loaded, and, if
necessary, moved to hotels for incubation of the next step. When
sample preparation is complete, the modular microchips can
interface with a high throughput CAE microchip, mass spectrometer,
flow cytometer, or other analysis devices.
[0008] The modular approach lets macroscale devices such as
automation and robotics work with nanoscale sample preparation and
analysis. The positional accuracy necessary for modular
manipulation is well within the existing capability of current
robotic systems and much less than required in the microelectronics
industry. Stages and stepper motors are now capable of less than 1
.mu.m positioning and greater than 5 .mu.m positioning is fairly
routine. Modular microchips can leverage the extensive automation
capabilities directly to accelerate development and deployment of
nanoscale devices.
[0009] The modular microfluidic approach can combine
microchip-based technologies with automation systems to create a
technology platform to completely automate nanoscale sample
preparation methods and link it to many types of analysis. In this
instant invention, examples of how to apply the invention to
develop DNA sequence sample preparation and analysis, AFLP
analysis, PCR analysis, MLVA analysis, cycle sequencing, DNA
fragment analysis for genotyping, and fragment analysis for DNA
sequencing.
[0010] In this invention, guidance is provided on how microscale
and nanoscale devices can be connected and how to perform sample
preparation and analysis on microchips. We also teach how to
connect different microchips that perform specialized functions
comprising microchip valves, reactors, movement of fluids, mixing,
performance of different biochemistries, and analysis methods.
SUMMARY OF THE INVENTION
[0011] In one aspect this invention provides a microfluidic device
comprising: a microfluidic layer, an actuation layer and elastomer
layer sandwiched between them, wherein: the microfluidic layer
comprises at least three microfluidic channels converging at a
nexus and separated by discontinuities that interrupt the flow of
fluid in said at least three microfluidic channels; the actuation
layer comprises at least one actuation channel opening into a valve
chamber, which valve chamber is disposed opposite the nexus; and
wherein displacement of said elastomeric membrane modulates fluid
flow across said at least three microfluidic channels, whereby a
diaphragm valve is formed. In one embodiment, the elastomeric
membrane simultaneously modulates fluid flow across said at least
three microfluidic channels. In another embodiment, the elastomeric
membrane prevents fluid flow across said at least three
microfluidic channels. In another embodiment, the elastomeric
membrane incompletely inhibits fluid flow across said at least
three microfluidic channels. In another embodiment, diaphragm valve
further comprises a vias layer. In another embodiment, the
application of pressure or a vacuum to said at least one actuation
channel causes said elastomeric membrane to modulate a flow of a
fluid across said discontinuities, thereby forming at least a three
channel valve. In another embodiment, the membrane naturally closes
the valve and application of vacuum to the membrane deflects the
membrane away from a valve seat, thereby opening the valve. In
another embodiment the microfluidic layer comprises a surface
facing the membrane, said surface comprising a groove which, when
pressed against the membrane, forms the microfluidic channel. In
another embodiment, the microfluidic layer comprises an internal
microfluidic channel that intersects a bore in the layer that opens
onto the nexus. In another embodiment, the actuation layer
comprises a surface facing the membrane, said surface comprising a
groove which, when pressed against the membrane, forms the
actuation channel. In another embodiment the actuation layer
comprises an internal actuation channel that opens onto the valve
chamber. In another embodiment, at least three microfluidic
channels converge at a nexus in a Y formation. In another
embodiment, a plurality of said diaphragm values is actuated by a
single actuation channel.
[0012] In another aspect this invention provides a microfluidic
device comprising: a microfluidic layer, an actuation layer and
elastomer layer sandwiched between them, wherein: the microfluidic
layer comprises first and second microfluidic channels converging
at a nexus and separated by discontinuities that interrupt the flow
of fluid between the first and second channels but not along the
second channel; the actuation layer comprises at least one
actuation channel opening into a valve chamber, which valve chamber
is disposed opposite the nexus; and wherein displacement of said
elastomeric membrane modulates fluid flow across said at least
three microfluidic channels, whereby a diaphragm valve is formed.
In one embodiment, the fluid flow in said second microfluidic
channel is not modulated by said elastomeric membrane. In another
embodiment, the elastomeric membrane prevents fluid flow across at
least one microfluidic channel. In another embodiment, the
elastomeric membrane incompletely inhibits fluid flow across at
least one microfluidic channel. In another embodiment, the
diaphragm valve further comprises a valve layer. In another
embodiment, the application of pressure or a vacuum to said at
least one actuation channel causes said elastomeric membrane to
modulate a flow of a fluid across at least one discontinuation. In
another embodiment, at least two microfluidic channels converge at
a nexus in a T formation. In another embodiment, a plurality of the
diaphragm valves are actuated by a single actuation channel. In
another embodiment, the second channel forms a loop having defined
volume and comprises a positive displacement pump of predetermined
volume. In another embodiment, a predetermined volume of liquid is
pumped into the first channel of a microstructure device by opening
the diaphragm valve and performing a plurality of strokes with the
pump.
[0013] In another aspect this invention provides a microfluidic
device comprising: a microfluidic layer, an actuation layer and a
elastomeric membrane layer sandwiched between them, wherein: the
microfluidic layer comprises a microfluidic channel; the actuation
layer comprises at least one actuation channel opening into a valve
chamber, which valve chamber is disposed along the microfluidic
channel; and wherein fluid flows along the channel whether or not
the elastomeric membrane is displaced, but displacement of said
elastomeric membrane modulates fluid flow along said channel,
thereby forming a diaphragm valve. In one embodiment, the
elastomeric membrane modulates fluid flow by increasing or
decreasing the cross section of said at least one microchannel. In
another embodiment, the diaphragm valve further comprises a vias
layer. In another embodiment, the application of pressure or a
vacuum to at least one actuation channel causes said elastomeric
membrane to modulate a flow of a fluid across at least one
discontinuation. In another embodiment, a microfluidic device
comprising a magnet that exerts a field at a diaphragm valve is
provided. In another embodiment. The magnet is selected from the
group consisting of a permanent magnet, an electromagnet, and a
rare earth magnet. In another embodiment, the pathway of at least
one microchannel forms a star or nested star adjacent to said
diaphragm valve.
[0014] In another aspect this invention provides a system
comprising: a first microfluidic device comprising: a first
microfluidic circuit comprising an inlet, an outlet, a pump and at
least one first functional component selected from a reactor, a
capture region, a temperature cycling zone, a hot zone, a cool
zone, separation channel, analysis circuit, mixer, bead processing
unit, and a magnet, wherein the pump is configured to pump fluid
through the circuit; and a second microfluidic device comprising: a
plurality of second microfluidic circuits, each comprising an
inlet, and outlet and at least one functional component which is
different than a first functional component; wherein the first and
second components are configured to engage in a plurality of
positions, wherein in each position the outlet of the first circuit
is mated with the inlet of one of the second circuits to allow
fluid to flow from the first circuit into the mated second circuit.
In one embodiment, the first microfluidic device further comprises
an electrode configured to move fluids, molecules, chemicals or
particles electrically. In another embodiment, the second
microfluidic device further comprises an analysis region. In
another embodiment, the second microfluidic device further
comprises a capture region. In another embodiment, the second
microfluidic device is mobile in comparison to said first
microfluidic device. In another embodiment, the fluid input of said
second microfluidic device delivers fluid from said first
microfluidic device to multiple microfluidic channels. In another
embodiment, the fluid output of said first microfluidic device
delivers fluid from multiple microfluidic channels to said fluid
input of said second microfluidic device. In another embodiment,
the fluids, molecules, chemicals or particles are moved
electrophoretically from said fluid output of said first
microfluidic device to said fluid input of said second microfluidic
device.
[0015] In another aspect this invention provides a method
comprising: a) performing a first operation on a first sample in
the first microfluidic circuit of the first microfluidic device of
claim 26; b) engaging the first and second microfluidic devices of
claim 26 so that the output of the first circuit is mated with the
inlet of a first of the second microfluidic circuits; c) moving
first sample after the operation from the first circuit into the
first of the second circuits; d) performing a second operation on
the received first sample in the first of the second circuits; e)
performing the first operation on a second sample in the first
microfluidic circuit; f) engaging the first and second microfluidic
devices so that the output of the first circuit is mated with the
inlet of a next, different one of the second microfluidic circuits;
g) moving second sample after the operation from the first circuit
into the next of the second circuits; and h) performing the second
operation on the first reacted sample in the first of the second
circuits. In one embodiment, a method is provided comprising
repeating steps e)-h) on at least one more sample in the first
circuit, wherein each sample is moved into a next different one of
the plurality of second circuits. In another embodiment, the first
operation comprises mixing a sample with a reagent. In another
embodiment, the first operation is performed in less time than the
second operation.
[0016] In another aspect this invention provides a method of making
a microfluidic device comprising: joining a plurality of layers to
form a plurality of microchannels and diaphragm valves; wherein
said plurality of layers are sandwiched together; wherein said at
least two layers of said plurality of layers are selected from the
group consisting of an elastomeric membrane, an actuation layer, a
microfluidic layer; a valve layer, heat spreaders, a vias layer, an
interface layer, and a cover layer. In one embodiment, at least one
of said plurality of layers is an adhesive layer. In another
embodiment, the plurality of layers is joined together by adhesive
layers. In another embodiment, the plurality of layers is joined
together by at least one clamp. In another embodiment, the
plurality of layers are joined except at the locations s of a
diaphragm valve by reducing the pressure or temperature at the
valve. In another embodiment, the plurality of layers are joined
except at the locations s of a diaphragm valve by selectively
placing a coating at the valve. In another embodiment, the coating
is removable.
[0017] In another aspect this invention provides a microfluidic
device comprising: a) a microfluidic channel; b) a first
temperature zone disposed along the channel having a temperature
above ambient temperature; c) a second temperature zone disposed
along the channel having a temperature below ambient temperature;
and d) a positive displacement pump disposed along the channel and
configured to pump liquid into the first and second temperature
zones. In one embodiment, a microfluidic device is provided
comprising a microfluidic loop that is thermally coupled to at
least one temperature zone. In another embodiment, a sample in at
least one microfluidic channel is pumped at least two times between
at least two different temperature zones. In another embodiment,
the sample is isolated from said at least one three valve pump by
an immiscible fluid. In another embodiment, at least one diaphragm
valve is located in a temperature zone.
[0018] In another aspect this invention provides a method of
analyzing a sample comprising: heating or cooling a nucleic acid
sequence in the microfluidic device of claim 41; analyzing said
nucleic acid sequence. In one embodiment, the analyzing comprises
sequencing, ligation or polymerase chain reaction amplification,
transcription, translation, or coupled transcription and
translation. In another embodiment, the nucleic acid is selected
from the group consisting of genomic DNA, mitochondrial DNA, mRNA,
tRNA, rRNA, siRNA. In another embodiment, the analyzing comprises
ligation of at least one adaptor to said nucleic acid sequence. In
another embodiment, the adaptor comprises a unique nucleic acid
sequence identifier. In another embodiment, the unique nucleic acid
sequence identifier is used as an internal quality control metric.
In another embodiment, the analyzing comprises binding of a single
nucleic acid sequence that has been ligated to a bead. In another
embodiment, a method is provided comprising amplification of a
nucleic acid sequence.
[0019] In another aspect this invention provides a microfluidic
device comprising: a microfluidic layer comprising a microfluidic
channel, wherein the channel comprises at least one tight bend
comprising two channel segments connected with each other and
oriented in an acute angle; and means for producing a magnetic
field that produces a magnetic field in the area of the tight bend,
wherein paramagnetic particles flowing through the tight bend are
retarded by the magnetic field. In one embodiment, a microfluidic
device is provided that comprises a plurality of tight bends.
[0020] In another aspect this invention provides a microfluidic
device comprising: a microfluidic layer comprising a microfluidic
channel, wherein the channel comprises a first, second and third
regions in sequence, wherein the second region has greater
cross-sectional area than the first and third regions; and means
for producing a magnetic field that produces a magnetic field in
the area of the second region, wherein paramagnetic particles
flowing through the second region are retarded by the magnetic
field. In one embodiment,
[0021] In another aspect this invention provides a method of
performing biomolecular analysis on a microfluidic device
comprising: mixing biomolecules and reagents in a first reaction
chamber on the microfluidic device to create a first reaction
mixture; moving the reaction mixture to a reaction area in the
device and performing a reaction to create a product mixture;
moving the product mixture to an area in the device and capturing
product on paramagnetic capture particles in the area; moving the
particles and captured product to a capture chamber in the device
that is within a magnetic field, so as to detain the capture
particles and product in the capture chamber; washing the particles
in the capture chamber; moving the particles and product to a port
on the device wherein the product can be removed from the device.
In one embodiment, the biomolecules are selected from nucleic acids
(DNA or RNA), proteins, carbohydrates, cells or lipids. In another
embodiment, the reaction is a nucleic acid amplification reaction.
In another embodiment, the amplification is isothermal. In another
embodiment, the amplification comprises thermal cycling of the
mixture. In another embodiment, a method is provided comprising
performing a second reaction on the reaction mixture or product
mixture.
[0022] In another aspect this invention provides a microfluidic
device comprising: a) a plurality of microfluidic reaction
circuits, each circuit comprising: at least two ports configured to
receive sample, or from which sample can be removed; at least one
pump configured to pump fluid through the circuit, at least one
reaction chamber comprising means for performing a chemical or
biochemical reaction; and at least one capture chamber comprising
means to capture particles; b) at least one dispensing port in
fluidic communication with a plurality of the microfluidic circuits
and configured to deliver sample or reagent fluid to each of the
circuits; wherein the plurality of circuits are configured to
perform operations in parallel on a plurality of different
materials delivered to one of the ports in each circuit. In one
embodiment, the reaction chamber is configured to be heated or
cooled by a thermal pump. In another embodiment, the capture
chamber is disposed in a magnetic field configured to retard the
movement of paramagnetic particles in the capture chamber. In
another embodiment, the pumps are positive displacement pumps.
INCORPORATION BY REFERENCE
[0023] All publications and patent applications mentioned in this
specification are herein incorporated by reference to the same
extent as if each individual publication or patent application was
specifically and individually indicated to be incorporated by
reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The novel features of the invention are set forth with
particularity in the appended claims. A better understanding of the
features and advantages of the present invention will be obtained
by reference to the following detailed description that sets forth
illustrative embodiments, in which the principles of the invention
are utilized, and the accompanying drawings of which:
[0025] FIG. 1 shows the application of a pump on a microchip to
move fluids from an input area to an output area.
[0026] FIG. 2 shows a Microscale On-chip Valve (MOV) that is
actuated by pneumatics.
[0027] FIG. 3 shows self-priming MOV pumps in the top panel,
routers in the top middle panel, mixers in the bottom middle panel,
and capture of beads in channels in the bottom panel.
[0028] FIG. 4 shows the application of using five valves to make a
fluidic circuit with two pumps on a microchip sharing a common
valve.
[0029] FIG. 5 shows a programmable microfluidic circuit mixing two
fluid streams on a microchip and movement to a reactor.
[0030] FIG. 6 shows a programmable microfluidic circuit mixing of
two streams and moving the mixed stream to an edge where it might
be coupled to another process.
[0031] FIG. 7 shows a programmable microfluidic circuit inputting
samples from an edge, combining the samples as the stream are
brought together in a microvalve, and moving them to a reactor
which could be a MOV valve.
[0032] FIG. 8 shows a programmable microfluidic circuit mixing and
loading a reactor connected to the edge
[0033] FIG. 9 shows a programmable microfluidic circuit that can
move samples from two chambers to a reactor and then move the
samples or product to an edge for further processing or
analysis.
[0034] FIG. 10 shows programmable microfluidic circuit moving the
sample from the reactor to a location where a second process might
occur such as another biochemical or chemical reaction.
[0035] FIG. 11 shows two devices where different functions are
performed on each device.
[0036] FIG. 12 shows where the analysis device may be coupled to
the sample preparation microchip with modular microfluidic
connections.
[0037] FIG. 13 shows microchips using modular microfluidic
connections with one or both microchips having electrodes.
[0038] FIG. 14 shows having a capture region on one device to
concentrate, purify, or capture a sample in a region and transfer
it to a second device.
[0039] FIG. 15 shows two channels each with a capture region.
[0040] FIG. 16 shows a device A with a capture region connected to
a device B with multiple analysis channels.
[0041] FIG. 17 shows a device with multiple electrodes connect to a
device with a capture region.
[0042] FIG. 18 shows connecting the device in FIG. 17 with a device
with two or more separation channels.
[0043] FIG. 19 shows in the top panel one circuit of an 8 channel
circuit on a MBI-026 microchip which includes MOV-based mixing, a
thermal cycling reaction, and bead-based sample cleanup; and in the
bottom panel the completed glass MBI-026 microchip.
[0044] FIG. 20 shows the readlength and signal to noise from the
MBI-026 microchip.
[0045] FIG. 21 shows automating microchips with microtiter
plates.
[0046] FIG. 22 shows a device, the Sample Capture and Purification
Module (SCPM) that uses immunomagnetic separations (IMS) and
pressure-driven flow to dispense magnetic beads, concentrate and
purify bioagents onto beads.
[0047] FIG. 23 shows an improved method of construction of a MOV
microvalve, termed a `Y-valve,` that has three connections.
[0048] FIG. 24 shows a MOV flowthrough valve where two or more
flows can be brought together.
[0049] FIG. 25 contrasts on the left using a microvalve that is not
at the junction on the left and an embodiment that connects a
flowthrough valve as shown in FIG. 24 with another channel to
eliminate the dead volume.
[0050] FIG. 26 shows using microfluidic circuits with features to
improve the trapping of paramagnetic particles.
[0051] FIG. 27 shows changing the cross sectional area of a
microfluidic channel to slow down flow and improve the trapping of
particles by magnetic, optical and other methods.
[0052] FIG. 28 shows changing the cross sectional area of a
microfluidic channel by opening a MOV microvalve to slow down flow
and improve the trapping of particles by magnetic, optical and
other methods.
[0053] FIG. 29 shows connecting a reservoir or other fluidic source
to multiple channels using MOV Y junctions.
[0054] FIG. 30 shows deliver of reagent or sample utilizing the
flow through valve to minimize the amount of dead volume at an
intersection that allows the channels at the intersection that can
be closed off from one another when desired.
[0055] FIG. 31 shows a loop that contains a microvalve such as a
MOV micropump.
[0056] FIG. 32 shows a programmable microfluidic circuit that
integrates multiple functions in a compact design.
[0057] FIG. 33 shows a hybrid plastic microchip.
[0058] FIG. 34 shows a programmable microfluidic circuit that
integrates multiple functions in a compact design using a star
processing design and a detector.
[0059] FIG. 35 shows the design of a mechanically clamped
microchip.
[0060] FIG. 36 shows a picture of a mechanically clamped microchip
from the top in the top panel and from the bottom in the bottom
panel.
[0061] FIG. 37 shows the layout of a mechanically clamped
microchip.
[0062] FIG. 38 shows assembly of a microchip using transfer tape or
adhesive coated materials.
[0063] FIG. 39 shows a microchip made from adhered layers.
[0064] FIG. 40 shows a close-up of a valve with adhered layers.
[0065] FIG. 41 shows an adhesive laminated microchip incorporating
heaters and heat spreaders.
[0066] FIG. 42 shows a plastic laminated microchip with a normally
closed valve that can be controlled by programmable pneumatics.
[0067] FIG. 43 shows a plastic laminated microchip with a normally
open valve that can be controlled by programmable pneumatics.
[0068] FIG. 44 shows four layer valve.
[0069] FIG. 45 shows a mask design top and a plastic microchip
fabricated for bead cleanup.
[0070] FIG. 46 shows the design on the top of a microchip that can
fabricated in plastic or other materials and the bottom shows a
photo of an acrylic microchip.
[0071] FIG. 47 shows using MOV pumps to move the sample between a
hot zone and a cool zone.
[0072] FIG. 48 shows using MOV pumps are used to move the sample
between three temperature zones.
[0073] FIG. 49 shows moving the sample between hot and cool zones
without passing through a pump.
[0074] FIG. 50 shows increasing the throughput by using multiple
samples moving between temperature zones in a multichannel thermal
cycling device.
[0075] FIG. 51 shows increasing the throughput by using multiple
samples moving between temperature zones in a multichannel thermal
cycling device with cleanup channels.
[0076] FIG. 52 shows two-temperature cycling in two
microvalves.
[0077] FIG. 53 shows three-temperature cycling in three
microvalves.
[0078] FIG. 54 shows three temperature shuttle cycling in
microvalves.
[0079] FIG. 55 shows a high level depiction of the workflow and
processes of the NanoBioPrep SuperPyroSequencing (NanoBioPrepSPS)
process.
[0080] FIG. 56 shows a NanoBioPrepSPS Ligation module for 42
ligation microchips.
[0081] FIG. 57 shows a 96 channel capillary cassette.
[0082] FIG. 58 shows two programmable microfluidic circuits for
ligation.
[0083] FIG. 59 shows a microchip with 96 ligations that uses
programmable microfluidic circuit.
[0084] FIG. 60 shows magnetic beads trapped in a star capture
region.
[0085] FIG. 61 shows a diagram of emPCR amplification.
[0086] FIG. 62 shows a thermal cycler using circulating water.
[0087] FIG. 63 shows a multiplexed latching microvalve device.
[0088] FIG. 64 shows thermal cycling in the emPCR module.
DETAILED DESCRIPTION OF THE INVENTION
[0089] In one aspect this invention provides guidance on the use of
programmable microfluidic circuits and devices to process
biochemical or chemical samples. In some embodiments microfluidic
processes are connected with inputs or sample volumes of milliliter
or centiliter scale. Further chemical and biochemical processes and
the integration of multiple processes are disclosed. In some
embodiments, microfabrication of microvalves with different designs
are taught.
[0090] In certain embodiments the microfluidic devices of this
invention comprise a microfluidic layer, an actuation layer and an
elastomeric membrane sandwiched therebetween. The fluidics layer
comprises fluidic channels adapted to allow the flow of liquid. In
certain embodiments, the fluidics channels are located on the
surface of the microfluidics layer that touches the elastomeric
membrane. In this embodiment, an open channel, furrow or groove can
be etched into the surface of the layer. In other embodiments, the
channel can be internal to the layer, e.g., in the form of a
tunnel, tube or via. The internal channel can access either surface
of the layer through bores from the surface into the channel. In
one method of making, two or more sub-layers can be effaced against
one another so that at least one sub-layer comprises a groove
forming the closed channel when two sub-layers are mated. In this
embodiment, one of the sub-layers comprises the bores that open
onto a surface, e.g., at a port or at a nexus to allow flow across
a valve. Diaphragm valves of this invention displace defined
volumes of liquid. When placed in a series of three, diaphragm
valves can function as a diaphragm pump, which functions as a
positive displacement pump. Modular devices of the invention can
comprise means to move modules with respect to one another (e.g.,
stepper motors) so that they can engage and mate fluidic channels
across the different modules, for example in sequence. This allows
coordination of rapid activities with slower ones by moving the
module with the rapid activity across the module with the slower
activity so that the rapid module delivers sample to each of the
circuits in the slower module. A first single sample can be divided
between many slower channels, or a number of different samples can
be delivered to each of the second circuits.
[0091] In another aspect microstructures are used to move fluid on
microchips. In some embodiments three or more valves can create
pumps to move fluids (including but not limited to, 4, 5, 6, 7, 8,
9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 valves). In one
embodiment the valves are diaphragm valves. Diaphragm valves can be
created by actuation of a deformable structure. In some embodiments
a diaphragm valve comprises a valve seat. In some embodiments the
diaphragm valve can allow or prevent fluid flow in a channel, such
as a microchannel. In other embodiments diaphragm valves are
created without a valve seat. In some embodiments the diaphragm
valve can control the flow speed of a fluid through a microchannel
by varying the cross-section of the channel. In another embodiment
the diaphragm valve incompletely inhibits fluid flow, in other word
the valve allows some fluid flow through the valve in both the open
and closed positions. FIG. 1 shows the application of a pump on a
microchip to move fluids from the Input area to the Output area on
Microchip A.
[0092] In another embodiment the microstructures are used to move
fluid which comprises analytes of interest. In one embodiment the
analyte is a particle. Wherein, particles includes proteins,
peptides, prions, toxins, infectious organisms (including but not
limited to, bacteria, viruses, fungi), cells (including but not
limited to, blood cells, white blood cells, NK cells, platelets,
skin cells, cheek cells, sperm cells, trophoblasts, macrophages,
granulocytes and mast cells), nucleic acids (such as DNA and RNA,
including but not limited to, mRNA, rRNA, tRNA, siRNA, mitochodrial
DNA, chromosomal DNA, genomic DNA, and plasmids), cell components,
(including but not limited to, a nucleus, a chromosome, a ribosome,
an endosome, a mitochondria, a vacuole, a chloroplast, and other
cytoplasmic fragments), carbohydrates (including but not limited
to, polysaccahrides, cellulose or chitin) and lipids (including,
but not limited to cholesterol, triglycerides). In another
embodiment the microstructures are used to move fluid which
comprises analytes of interest, such as molecules or chemicals,
(including but not limited to, dioxin, PCBs, heavy metals,
organophosphates, estrogenic mimetics, rBST, drug metabolites,
carcinogens or tetratogens)
[0093] In another aspect microstructures are used in sample capture
and purification, such as micro-separations, micro-valves, -pumps,
and -routers, nanofluidic control, and nano-scale biochemistry. In
one embodiment microstructures are used to miniaturize and automate
complex workflows (FIG. 2). In one embodiment the Microscale
On-chip Valves (MOV) valves, pumps, and routers and the
instrumentation to operate them comprise a NanoBioProcessor
platform. In another embodiment the microchip comprises
microstructures that comprise one or more functional components,
including, but not limited, to a reactor, a capture region, a
temperature cycling zone, a hot zone, a cool zone, separation
channel, analysis circuit, mixer, bead processing unit, a heat
spreader, a pettier device, and a magnet. In some embodiments the
capture zone may comprise binding moieties linked to a substrate,
including, but not limited, antibodies, Fc fragments, Fab
fragments, lectins, polysaccharides, receptor ligands, DNA
sequences, PNA sequences, siRNA sequences, or RNA sequences. In
another embodiment, one or more regions of the microstructure may
comprise beads, such as magnetically responsive beads. In some
embodiments the beads may comprise binding moieties, including, but
not limited, antibodies, Fc fragments, Fab fragments, lectins,
polysaccharides, receptor ligands, DNA sequences, PNA sequences,
siRNA sequences, or RNA sequences. In some embodiments the
magnetically responsive beads have dimensions smaller than 600 nm,
such as 590 nm, 580 nm, 570 nm, 560 nm, 550 nm, 540 nm, 530 nm, 520
nm, 510 nm, 500 nm, 490 nm, 480 nm, 470 nm, 460 nm, 450 nm, 440 nm,
430 nm, 420 nm, 410 nm, 400 nm, 390 nm, 380 nm, 370 nm, 360 nm, 350
nm, 340 nm, 330 nm, 320 nm, 310 nm, 300 nm, 290 nm, 280 nm, 270 nm,
260 nm, 250 nm, 240 nm, 230 nm, 220 nm, 210 nm, 200 nm, 190 nm, 180
nm, 170 nm, 160 nm, 150 nm, 140 nm, 130 nm, 120 nm, 110 nm, 100 nm,
90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, or 10 nm.
In some embodiments the magnetically responsive beads comprise an
iron compound. In one embodiments the magnetically responsive beads
is a ferrite bead.
[0094] In some embodiments, a magnetic bead has a diameter that is
between 10-1000 nm, 20-800 nm, 30-600 nm, 40-400 nm, or 50-200 nm.
In some embodiments, a magnetic bead has a diameter of more than 10
nm, 50 nm, 100 nm, 200 nm, 500 nm, 1000 nm, or 5000 nm. The
magnetic beads can be dry or suspended in a liquid. Mixing of a
fluid sample with a second liquid medium containing magnetic beads
can occur by any means known in the art including those described
in U.S. Ser. No. [Not Assigned], entitled "Methods and Systems for
Fluid Delivery," filed Sep. 15, 2005.
[0095] In some embodiments, when an analyte in a sample (e.g.,
analyte of interest or not of interest) is ferromagnetic or
otherwise has a magnetic property, such analyte can be separated or
removed from one or more other analytes (e.g., analyte of interest
or not of interest) or from a sample depleted of analytes using a
magnetic field. For example, a first analyte is coupled to
antibodies that specifically bind the first analyte and wherein the
antibodies are also coupled to magnetic beads. When a mixture of
analytes comprising the first analyte-magnetic bead complex and a
second analyte are delivered into a magnetic field, the first
analyte-magnetic bead complex will be captured while other cells
continue to migrate through the field. The first analyte can then
be released by removing the magnetic field.
[0096] The magnetic field can be external or internal to the
microstructures disclosed herein. An external magnetic field is one
whose source is outside a device herein (e.g., microchip, diaphragm
valve, channel, obstacles) contemplated herein. An internal
magnetic field is one whose source is within a device contemplated
herein. In some embodiments the magnetic filed is generated by an
electromagnet or a permanent magnet, such as a rare earth magnet.
In some embodiments the magnet is mobile and can be moved in
relation to the microstructure.
[0097] In some embodiments, when an analyte desired to be separated
(e.g., analyte of interest or not of interest) is not ferromagnetic
or does not have a magnetic property, a magnetic bead can be
coupled to a binding moiety that selectively binds such analyte.
Examples of binding moieties include, but are not limited to,
lectins, polypeptides, antibodies, nucleic acids, etc. In preferred
embodiments, a binding moiety is an antibody or antibody fragment
(such as Fab, Fc, sfv) that selectively binds to an analyte of
interest (such as a red blood cell, a cancer cell, a sperm cell, a
nuclei, a chromosome, a white blood cell, an epithelial cell, a
bacterium, a virus or fungi). Therefore, in some embodiments a
magnetic bead may be decorated with an antibody (preferably a
monoclonal antibody).
[0098] Magnetic particles may be coupled to any one or more of the
microstructures disclosed herein prior to contact with a sample or
may be mixed with the sample prior to delivery of the sample to the
device(s).
[0099] In some embodiments, the systems herein include a reservoir
containing a reagent (e.g., magnetic beads) capable of altering a
magnetic property of the analytes captured or not captured. The
reservoir is preferably fluidly coupled to one or more of the
microstructures disclosed herein. For example, in some embodiments,
a magnetic reservoir is coupled to a size-microchannel and in other
embodiments a magnetic reservoir is coupled to a capture
region.
[0100] The exact nature of the reagent will depend on the nature of
the analyte. Exemplary reagents include agents that oxidize or
reduce transition metals, reagents that oxidize or reduce
hemoglobin, magnetic beads capable of binding to the analytes, or
reagents that are capable of chelating, oxidizing, or otherwise
binding iron, or other magnetic materials or particles. The reagent
may act to alter the magnetic properties of an analyte to enable or
increase its attraction to a magnetic field, to enable or increase
its repulsion to a magnetic field, or to eliminate a magnetic
property such that the analyte is unaffected by a magnetic
field.
[0101] Any magnetic bead that responds to a magnetic field may be
employed in the devices and methods of the invention. Desirable
particles are those that have surface chemistry that can be
chemically or physically modified, e.g., by chemical reaction,
physical adsorption, entanglement, or electrostatic
interaction.
[0102] In some embodiments capture moieties can be bound to
magnetic beads by any means known in the art. Examples include
chemical reaction, physical adsorption, entanglement, or
electrostatic interaction. The capture moiety bound to a magnetic
bead will depend on the nature of the analyte targeted. Examples of
capture moieties include, without limitation, proteins (such as
antibodies, avidin, and cell-surface receptors), charged or
uncharged polymers (such as polypeptides, nucleic acids, and
synthetic polymers), hydrophobic or hydrophilic polymers, small
molecules (such as biotin, receptor ligands, and chelating agents),
carbohydrates, and ions. Such capture moieties can be used to
specifically bind cells (e.g., bacterial, pathogenic, fetal cells,
fetal blood cells, sperm cells, cancer cells, and blood cells),
organelles (e.g., nuclei), viruses, peptides, proteins,
carbohydrates, polymers, nucleic acids, supramolecular complexes,
other biological molecules (e.g., organic or inorganic molecules),
small molecules, ions, or combinations (chimera) or fragments
thereof.
[0103] Once a magnetic property of an analyte has been altered, it
may be used to effect an isolation or enrichment of the analyte
relative to other constituents of a sample. The isolation or
enrichment may include positive selection by using a magnetic field
to attract the desired analytes to a magnetic field, or it may
employ negative selection to attract an analyte not of interest. In
either case, the population of analytes containing the desired
analytes may be collected for analysis or further processing.
[0104] In some embodiments the microstructures are used in a method
of analysis, wherein at least one molecule, particle or chemical is
analyzed. In one example a nucleic acid is analyzed. Analysis
includes, but is not limited to, ligation or polymerase chain
reaction amplification, transcription, translation, coupled
transcription and translation. In another example a labeled binding
moiety is bound to a target analyte (such as a cell, protein, cell
fragment, or nucleic acids). Wherein, the binding moiety includes,
but is not limited to, an antibody, antibody fragment, receptor,
receptor ligand, lectin, polysaccharide, or nucleic acid. Wherein,
the label includes, but is not limited to, fluorescent labels
(including, but not limited to, FITC, PE, Texas RED, Cyber Green,
JOE, FAM, HEX, TAMRA, ROX, Alexa 488, Alexa 532, Alexa 546, Alexa
405 or other flurochromes), radioactive labels (including, but not
limited to, P.sub.32, H.sub.3, or C.sub.14), fluorescent proteins
(including, but not limited to, GFP, RFP, or YFP), quantum dots,
gold particles, sliver particles, biotin, beads (including but not
limited magnetic beads or polystyrene beads).
[0105] In some embodiments MOV pumps, valves, and routers that
transport, process, and enable analysis of samples are disclosed.
Externally actuated, pneumatically-driven, on-chip valves, pumps,
and routers) can control fluidic flow at manipulate volumes from 10
nL to 10 uL; including but not limited to 10 nl, 11 nl, 12 nl, 13
nl, 14 nl, 15 nl, 16 nl, 17 nl, 18 nl, 19 nl, 20 nl, 21 nl, 22 nl,
23 nl, 24 nl, 25 nl, 26 nl, 27 nl, 28 nl, 29 nl, 30 nl, 35 nl, 40
nl, 45 nl, 50 nl, 55 nl, 60 nl, 65 nl, 70 nl, 75 nl, 80 nl, 85 nl,
90 nl, 95 nl, 100 nl, 110 nl, 120 nl, 130 nl, 140 nl, 150 nl, 160
nl, 170 nl, 180 nl, 190 nl, 200 nl, 250 nl, 300 nl, 350 nl, 400 nl,
450 nl, 500 nl, 550 nl, 600 nl, 650 nl, 700 nl, 750 nl, 800 nl, 850
nl, 900 nl, 950 nl, 1000 nl, 1.1 ul, 1.2 ul, 1.3 ul, 1.4 ul, 1.5
ul, 1.6 ul, 1.7 ul, 1.8 ul, 1.9 ul, 2.0 ul, 2.5 ul, 3.0 ul, 3.5 ul,
4.0 ul, 4.5 ul, 5.0 ul, 5.5 ul, 6.0 ul, 6.5 ul, 7.0 ul, 7.5 ul, 8.0
ul, 8.5 ul, 9.0 ul, 9.5 ul, 10.0 ul (see, Grover, W. H. et al.,
2003. Sensors and Actuators B89:315-323; U.S. patent application
Ser. No. 10/750,533; U.S. patent application Ser. No. 10/540,658;
all of which are herein incorporated by reference in their
entirety).
[0106] In one embodiment the MOV valves and pumps combine two glass
microfluidic layers with a polydimethyl siloxane (PDMS) deformable
membrane layer that opens and closes the valve, and a pneumatic
layer to deform the membrane and actuate the valve (FIG. 2). The
microfluidic channel etched in the top glass fluidic wafer is
discontinuous and leads to vias through the "via wafer" and
microfluidic channels to a valve seat which is normally closed
(FIG. 2 top panel). When a vacuum is applied to the pneumatic
displacement chamber by conventional-scale vacuum and pressure
sources, the normally closed PDMS membrane lifts from the valve
seat to open the valve (FIG. 2 middle panel). The bottom panel of
FIG. 2 shows a top view of the valve as the same scale as the other
panels.
[0107] In another embodiment, self-priming MOV pumps (FIG. 3, top)
are made by coordinating the operation of three or more valves and
can create flow in either direction. In another embodiment, routers
are made from three or more MOV valves (FIG. 3, top middle panel).
In another embodiment, MOV mixers (FIG. 3, bottom middle panel)
rapidly mix samples and reagents. In a further embodiment, MOV
devices work exquisitely with magnetic beads to pump or trap sets
of beads (FIG. 3, bottom panel).
[0108] The normally closed MOV valves, pumps, and routers are
durable, easily fabricated at low cost, can operate in dense
arrays, and have low dead volumes. Arrays of MOV valves, pumps, and
routers are readily fabricated on microchips, such as
NanoBioProcessor microchips. In one embodiment, all the MOV valves,
pumps, and routers on a microchip are created at the same time in a
simple manufacturing process using a single membrane, such as a
sheet of Teflon, silicone elastomers, polydimethylsiloxane (PDMS),
polyimide, Mylar, Latex, Viton, polycarbonate, acrylic, santaprene,
polyurethane, or buna. This technology provides the ability to
create complex micro- and nanofluidic circuits on microchips.
[0109] In one aspect methods of manufacturing a microfludic
structure are disclosed. In one embodiment the structure is
manufactured by sandwiching multiple layers of material together to
form a complete microfludic structure. In one embodiment these
layers are joined together through the use of adhesives (FIGS.
38-41). In another embodiment the layers are joined together by at
least one clamp, including but not limited to 2, 3, 4, 5, 6, 7, 8,
9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 40, 45, or
50 clamps (FIGS. 35 and 36). In another embodiment the layers are
joined together by a combination of adhesives and clamps or pins.
In one embodiment the multiple layers of material which are
sandwiched together comprise at least three layers selected from
the group consisting of a top cover, microfluidics layer, a vias,
an interface, a membrane, a pneumatics layer, a bottom cover, a
heat spreader, a heater, an actuation layer and a valve layer. In
another embodiment the layers are comprised of more than one
substrate. For example, substrates that can be used to create
microvalves include, but are not limited to, quartz, glass (such as
borosilicate glass, include, but are not limited to, pyrex,
borofloat, Corning 1737), silicon, and plastics (including, but not
limited to, acrylic, polycarbonate, liquid crystal polymer,
polymethylmethoxyacrylate (PMMA), Zeonor, polyolefin,
polypropylene, and polythiols). In another example substrates that
can be used as membranes include, but are not limited to, Teflon,
silicone elastomers, polydimethylsiloxane (PDMS), polyimide, Mylar,
Latex, Viton, polycarbonate, acrylic, santaprene, polyurethane, and
buna. In another example substrates that can be used as adhesives
include, but are not limited to, transfer tape, adhesive coated
tape such as silicone based, acrylic, or other materials in thin
sheets or films.
[0110] In some embodiments the microstructure comprises multiple
microchannels. In some embodiments the microchannels have the same
width and depth. In other embodiments the micro channels have
different widths and depths. In one embodiment a microchannel is
characterized as having a channel wider than the average size of an
analyte of interest in a sample delivered to the microstructure. In
another embodiment a micro channel has a width equal to or larger
than the largest analyte (such as the largest cell) separated from
the sample. For example, in some embodiments, a microchannel in a
microstructure can have a width greater than 50, 60, 70, 80, 90,
100, 110, 120, 130, 140, 150 microns. In some embodiments, a
microchannel has a width of less than 100, 90, 80, 70, 60, 50, 40,
30, or 20 microns. In some embodiments a microchannel in a
microstructure can have a depth greater than 50, 60, 70, 80, 90,
100, 110, 120, 130, 140, 150 microns. In some embodiments, a
microchannel has a depth of less than 100, 90, 80, 70, 60, 50, 40,
30, or 20 microns. In some embodiments a microchannel has side
walls that are parallel to each other. In some other embodiments a
microchannel has a top and bottom that are parallel to each other.
In some other embodiments a microchannel comprises regions with
different cross sections. In some embodiments, a microchannel has a
cross section in the shape of a cheese wedge, wherein the pointed
end of the wedge is directed downstream.
[0111] In some embodiments microchannels or microstructures are
etched as grooves or trenches into a substrate. In some embodiments
holes may be drilled, bored, cut or etched through a substrate. In
other embodiments microchannels are formed in a substrate as a
tunnel or a bore that is enclosed within the substrate of a single
layer of a microchip.
[0112] In some embodiments microstructures are formed using
standard photolithography. For example, photolithography can be
used to create a photoresist pattern of obstacles on a
silicon-on-insulator (SOI) wafer. A SOI wafer consists of a 100
.mu.m thick Si(100) layer atop a 1 .mu.m thick SiO.sub.2 layer on a
500 .mu.m thick Si(100) wafer. To optimize photoresist adhesion,
the SOI wafers may be exposed to high-temperature vapors of
hexamethyldisilazane prior to photoresist coating. UV-sensitive
photoresist is spin coated on the wafer, baked for 30 minutes at
90.degree. C., exposed to UV light for 300 seconds through a chrome
contact mask, developed for 5 minutes in developer, and post-baked
for 30 minutes at 90.degree. C. The process parameters may be
altered depending on the nature and thickness of the photoresist.
The pattern of the contact chrome mask is transferred to the
photoresist and determines the geometry of the microstructures.
[0113] Upon the formation of the photoresist pattern that is the
same as that of the microstructures, the etching is initiated.
SiO.sub.2 may serve as a stopper to the etching process. The
etching may also be controlled to stop at a given depth without the
use of a stopper layer. The photoresist pattern is transferred to
the 100 .mu.m thick Si layer in a plasma etcher. Multiplexed deep
etching may be utilized to achieve uniform microstructures. For
example, the substrate is exposed for 15 seconds to a fluorine-rich
plasma flowing SF.sub.6, and then the system is switched to a
fluorocarbon-rich plasma flowing only C.sub.4F.sub.8 for 10
seconds, which coats all surfaces with a protective film. In the
subsequent etching cycle, the exposure to ion bombardment clears
the polymer preferentially from horizontal surfaces and the cycle
is repeated multiple times until, e.g., the SiO.sub.2 layer is
reached.
[0114] To couple a binding moiety to the surfaces of the obstacles,
the substrate may be exposed to an oxygen plasma prior to surface
modification to create a silicon dioxide layer, to which binding
moieties may be attached. The substrate may then be rinsed twice in
distilled, deionized water and allowed to air dry. Silane
immobilization onto exposed glass is performed by immersing samples
for 30 seconds in freshly prepared, 2% v/v solution of
3-[(2-aminoethyl)amino] propyltrimethoxysilane in water followed by
further washing in distilled, deionized water. The substrate is
then dried in nitrogen gas and baked. Next, the substrate is
immersed in 2.5% v/v solution of glutaraldehyde in phosphate
buffered saline for 1 hour at ambient temperature. The substrate is
then rinsed again, and immersed in a solution of 0.5 mg/mL binding
moiety, e.g., anti-CD71, in distilled, deionized water for 15
minutes at ambient temperature to couple the binding agent to the
obstacles. The substrate is then rinsed twice in distilled,
deionized water, and soaked overnight in 70% ethanol for
sterilization.
[0115] There are multiple techniques other than the method
described above by which binding moieties may be immobilized onto
regions of the microstructures and the surfaces of the device.
Simply physio-absorption onto the surface may be the choice for
simplicity and cost. Another approach may use self-assembled
monolayers (e.g., thiols on gold) that are functionalized with
various binding moieties. Additional methods may be used depending
on the binding moieties being bound and the material used to
fabricate the device. Surface modification methods are known in the
art. In addition, certain cells may preferentially bind to the
unaltered surface of a material. For example, some cells may bind
preferentially to positively charged, negatively charged, or
hydrophobic surfaces or to chemical groups present in certain
polymers.
[0116] The microstructure device may be made out of different
materials including, but not limited to, pyrex, borofloat, Corning
1737, silicon acrylic, polycarbonate, liquid crystal polymer,
polymethylmethoxyacrylate (PMMA), Zeonor, polyolefin, polystyrene,
polypropylene, and polythiols. Depending on the choice of the
material different fabrication techniques may also be used. The
device may be made out of plastic, such as polystyrene, using a hot
embossing technique. The obstacles and the necessary other
structures are embossed into the plastic to create the bottom
surface. A top layer may then be bonded to the bottom layer.
Injection molding is another approach that can be used to create
such a device. Soft lithography may also be utilized to create
either a whole chamber out of plastic or only partial
microstructures may be created, and then bonded to a glass
substrate to create the closed chamber. Yet another approach
involves the use of epoxy casting techniques to create the
obstacles through the use of UV or temperature curable epoxy on a
master that has the negative replica of the intended structure.
Laser or other types of micromachining approaches may also be
utilized to create the flow chamber. Other suitable polymers that
may be used in the fabrication of the device are polycarbonate,
polyethylene, and poly(methyl methacrylate). In addition, metals
like steel and nickel may also be used to fabricate the device of
the invention, e.g., by traditional metal machining.
Three-dimensional fabrication techniques (e.g., stereolithography)
may be employed to fabricate a device in one piece. Other methods
for fabrication are known in the art.
Mixing Fluids
[0117] The ability to mix fluids on microchips and capillaries is
disclosed. FIG. 4 shows the application of using five valves to
make a fluidic circuit with two pumps on a microchip sharing a
common valve. The terms fluidics includes without limitation to
connote simple liquids with only one component, mixtures, liquids
containing beads, particles, gels, and other materials well known
to one skilled in the art, gases, and other matrices. The circuit
can move fluids from two Input area, mix them and deliver the
mixture to the Output area on Microchip A. The individual fluid
streams can be moved by pumps comprising three or more valves
including MOV valves or other valves. The streams can contain
samples, reagents, buffers, and other components. The valves can be
created actuation of a deformable structure, changes in
temperature, pressure. Two (FIG. 3, bottom middle panel) or more
streams (FIG. 3, upper middle panel) can be combined using MOV and
other microvalves. In one embodiment the MOV valves are self
priming and are under computer control, they may be driven in
either direction and the same circuit can be used to split a sample
into two streams by simply running the two co joined pumps to move
samples from the area labeled Output to the two areas labeled
Input.
[0118] FIG. 5 illustrates mixing two fluid streams on a microchip
and movement to a reactor. In some embodiments the reactor could be
located in a MOV valve to improve optical path lengths for
detection, the surface-to-volume ratio, thermal control, and other
advantages. In the examples that follow, additional methods to
perform reactions with microchips with microvalves such as MOV
valves, pumps, and routers are disclosed.
[0119] FIG. 6 illustrates the mixing of two streams, and moving the
mixed stream to an edge where it may be coupled to another process.
The mixing may be done with MOV valves.
[0120] FIG. 7 illustrates inputting samples from an edge, combining
the samples as the stream are brought together in a microvalve, and
moving them to a reactor which could be a MOV valve or a chamber
created using the deflection of a membrane, for example an
elastomeric membrane such as polydimethylsiloxane (PDMS).
[0121] Three or more streams can also be combined with a MOV valve,
(FIG. 3, upper middle panel), and moved into a reactor (FIG. 8).
The streams can contain liquids, particles, magnetic beads,
nanoparticles, colloids, gases, and other material. The MOV valves
enable facile manipulation of magnetic and other beads and
particles as well as fluids.
Reactions on Microchips
[0122] In one aspect a sample can be moved to a reactor, FIG. 8,
comprised of an etched channel, a microvalve, a vial, flows cell, a
capillary, reservoir, or other structures well known to one skilled
in the art. MOV valves can be used to create microchips which
combine two or more streams to perform different biochemistries.
The sample can then be interrogated in the reactor. This can
include, but is not limited to, optical sensing such as LIF,
absorbance, chemiluminescence, surface plasmon resonance.
[0123] FIG. 9 illustrates the use of two ganged pumps to move
samples to a reactor and then further move the sample or product to
an edge for further processing or analysis as will be enabled
below. The term sample includes, but is not limited, a fluid
comprising an analyte of interest, a material comprised of a single
compound or element, a complex sample such as bodily fluids,
aerosols, mixtures, biological or chemical materials, including
DNA, RNA, microRNAs, proteins, lipids, polysaccharides, cell walls,
small molecules, and all other biological components of a
biological sample, fluids comprising microbeads or particles.
Further, a sample may be combined with one or more reagents prior
to delivery to the microstructure.
[0124] FIG. 10 illustrates moving two samples from an edge to a
reactor and then to a location where a second process can occur,
such as another biochemical or chemical reaction. The location can
also be used to output a sample using a microfluidic device to move
the sample to a robot to pipette or other mechanisms. Beads
including magnetic beads can be used to move the sample when
desired.
Integration of Two or More Processes
[0125] In another aspect, modular microfluidic docking and
undocking are extended to use two or more processes where one or
more microchips incorporate MOV valves, pumps, and routers. FIG. 11
shows one embodiment where Device A prepares samples which are then
analyzed on Device B. In one embodiment the devices may be
microchips or full scale devices using tubing, plumbing, or other
means to prepare samples. In another preferred embodiment, Device B
may be a capillary, a separate instrument comprising a capillary
electrophoresis system or microchip capillary electrophoresis;
multidimensional gel and capillary electrophoresis; mass
spectroscopy, multidimensional mass spectroscopy with HPLC, ICP,
Raman spectroscopy, particle, nanoparticles, and bead based
detection, imaging, comprising fluorescence, IR, optical, or any
other analytical systems well know to one in the art. The streams
or fluids can be placed in reservoirs as in FIG. 6 before
processing on Device A or come from the sides or other geometries
as shown in FIG. 11. In this manner, a microchip, microchip A, with
sample preparation functions such as reactions, routers, sample
cleanup, may be used to prepare samples by many means including
PCR, cycle sequencing, sandwich assays, isothermal nucleic acid
amplifications, isotachaphoresis, isoelectric focusing,
hybridization, affinity capture, or other methods well known to one
skilled in the art. The sample can then be moved to Device B which
can be a microchip, mass spectrometer, analytical instrument, or
other detector including separation devices where the prepared
sample may be analyzed.
[0126] FIG. 12 illustrates where the analysis device may be coupled
to a sample preparation microchip with modular microfluidic
connections. A sample can then be moved from Device A to Device B
by MOV pumps, external pressure pumps, electroosmotic flow,
magnetic separations, or other methods.
[0127] In one embodiment an electrode can be incorporated to move
the sample by electrical potential, such as electrophoresis. FIG.
13 shows one configuration. In one embodiment an analyte of
interest is moved in a first direction. In another embodiment an
analyte not of interest is moved in a second direction. In some
embodiments multiple electrodes can be used. In one example, a
sample may be processed in a reactor and then pumped to the region
where an electrical potential can move the sample from a device A
into an analysis device B. This can occur when the two devices are
moved to a proximal location which may include direct physical
contact, close contact with a small gap, or further distant contact
separated by a connector or interface. The circuit can be completed
by use of one or more electrodes on Device B to produce an
electrical field that moves the sample or components of the sample
into Device B. In another embodiment additional electrodes are
present in a downstream device that Device B is attached to. In
another embodiment one or more electrodes are present in a
reservoir that connects to Device B (FIG. 13).
[0128] In another embodiment a sample can also be moved using MOV
micropumps or other means to a capture region which may have
capture moieties or binding moieties attached. In some embodiment
the capture region can be used in a method such as hybridization,
affinity capture, or other methods known to one skilled in the art.
In another embodiment the capture region may comprise a
non-specific capture means such as hydrophobic or hydrophilic
properties, solid phase extraction, metal binding, adsorption,
non-covalent interactions, covalent, light induced binding or other
means to capture an analyte of interest or not of interest (FIG.
14). In one embodiment microchip A and Device B can be moved
together as by modular microfluidics. In one embodiment the capture
region can be used as a region for injection into an analytic
device comprised as a capillary electrophoresis (CE) instrument,
microchip with CE, capillary array electrophoresis (CAE). The
microchip A can then be moved adjacent to microchip B which can
have functions, including, but not limited to, capillary array
electrophoresis (CAE), mass spectrometry, HPLC, PCR, isothermal
nucleic acid amplifications, isotachaphoresis, isoelectric
focusing, hybridization, affinity capture. In another embodiment
the capture region can be used to concentrate the sample or purify
the sample before movement to a second device which may perform
additional sample preparation or analysis.
[0129] In one example, two devices, such as microchips, are brought
either in contact or close to each other. FIG. 15 shows two
channels each with a capture region. The channels can then move the
samples close to device B. An electrical potential can then be
applied to move the sample from the region for injection into
device B. With sufficient voltage the sample can `hop` across a
gap. The sample will be quantitatively injected onto device B if so
desired. The number of channels can be adjusted such that device A
could have many more channels than device B and do repeated
injections or device A could have fewer channels than device B. In
a preferred embodiment, Device B is a microchip containing
separation channels for CAE. In one embodiment Device B could
comprise separation capillaries that in one embodiment might be
connected through a modular microfluidic interfaces. For a 2D
separation, where the first dimension was an isoelectric focusing
in Device A, Device B may be repeatedly moved and a portion of a
sample in microchip A can be injected into multiple microchannels
on microchip B. FIG. 16 illustrates a device A with a capture
region connected to a device B with multiple microchannels, which
can be used for analyte analysis, such as CAE, mass spectroscopy,
HPLC.
[0130] In one embodiment injection of samples into a microchip uses
a "Twin T" injector. While the Twin T defines a small plug between
the Twin Ts, as the sample is moved across the Twin T, a separation
may occur as a sample is electrophoresed from a sample reservoir to
the waste. (Liu S, Ren H, Gao Q, Roach D J, Loder R T Jr, Armstrong
T M, Mao Q, Blaga I, Barker D L, Jovanovich S B. Automated parallel
DNA sequencing on multiple channel microchips. Proc Natl Acad Sci
USA. 2000 May 9; 97(10):5369-74.).
[0131] In another embodiment a separation channel is fabricated in
one device while the injector is fabricated on a second device. In
some embodiments, the two devices can be docked or undocked.
[0132] In one embodiment, a sample is moved to a capture region on
a separate capillary, microchip or other device. FIG. 17 shows a
device which may be a microchip on the right with a capture region.
A sample can be moved using first pumping by MOV valves and then
electrical field to remove uncaptured analytes and purify the
sample. In one embodiment a microchip with the capture region is
then moved to a separation device as shown in FIG. 18, the complete
sample can then be injected after desorption. The desorption might
be by changing the temperature, chemical means, light desorption,
or other methods well known to one skilled in the art.
Integration of Processes on Microchip for Sample Preparation and
Cleanup
[0133] In one aspect MOV technology can be applied to
microchip-based sample preparation and analysis for many fields
such as DNA sequencing, biodefense, forensics, proteomics and cell
biology. In one embodiment MOVE technology can be used to perform
automated cycle nucleic acid sequencing and cleanup, such as Sanger
sequencing. FIG. 19, top panel, illustrates one circuit of an 8
channel circuit on a MBI-026 microchip which includes MOV-based
mixing, a thermal cycling reaction, and bead-based sample cleanup;
the completed glass microchip is shown in the bottom panel. The
MBI-026 has been used to demonstrate readlengths of over (FIG. 20)
1,000 bases of Phred 15 data on a modified MegaBACE DNA Analysis
instrument using on-chip integrated cycle sequencing and cleanup to
prepare Ready-to-Inject.TM. sequencing samples. By using PowerPlex
16 STR reactions on the MBI-026 microchip MBI has demonstrated
16-plex STR PCR amplification for forensics. Many of the elements,
i.e. MOV mixer, pumps, and valves, of the MBI-026 microchip can be
used in a wide range of applications.
[0134] In one aspect the operation of the MBI-026 microchip using
NanoBioProcessor technology can be automated using one or more
robots (FIG. 21). In one embodiment a robot under software control
moves samples using either fixed tip or probes from a microtiter
plate to a microchip (such as MBI-026) that is contained in an
interface device. In one embodiment a microchip interfaces with a
device that can contain functions to heat and cool the microchip.
The heating device can comprise resistive heaters attached to the
microchip, as shown in FIG. 19. In other embodiments the microchip
is heated using resistive heaters located off the microchip, by
using air or gases of different temperatures, by using infrared
heating, Peltier/thermoelectric heating, contact with fluidics of
different temperatures, or other means. In some embodiments the
microchip is cooled by using air or other gases (such as
refrigerants), Peltier devices, contact with liquids (such as
refrigerants), or other means well known to one skilled in the
art.
Interface with Large Volume Samples
[0135] In one aspect microfluidic devices, such as microchips are
connected either directly or indirectly to devices that prepare a
sample for the microfluidic device. The sample may be concentrated
and/or purified.
[0136] In one embodiment, environmental aerosols are processed
using fluidics to prepare samples for further microchip sample
preparation and analysis. FIG. 22 shows a device, the Sample
Capture and Purification Module (SCPM) that uses immunomagnetic
separations (IMS) and pressure-driven flow to dispense magnetic
beads, concentrate and purify bioagents onto beads. In one
embodiment a prepared sample may be eluted from the beads and the
eluate moved to a downstream device such as a microchip or the
beads may be moved to the downstream device. In one embodiment, the
beads may be introduced into microchips for miniaturized Real-Time
PCR and/or microscale capillary array electrophoresis (.mu.CAE). In
some embodiments a vibrating mixer which can vibrate to mix the
samples, reagents and beads can be used with a microchip (FIG. 22).
In another embodiment an actuation moves magnet to trap and release
magnetic beads (such as paramagnetic beads) in a
microstructure.
[0137] In one embodiment hardware can be operated by software such
as MBI's DevLink.TM. software or embedded software. DevLink defines
a set of communication and command protocols in a standardized
automation architecture that is simpler, more flexible, and quicker
to implement than other software development approaches. The
DevLink implementation framework is based on core technologies that
span multiple operating systems, development languages, and
communication protocols. Software drivers wrap individual smart
components of the system, greatly reducing the time needed for
typical de novo system software development. Integrating the
operation of multiple system modules (pumps, valves, temperature
controllers, I/O controllers, etc.) that are either COM- or
.NET-based is straightforward. DevLink provides a professional
quality software development system for prototyping through product
release and maintenance.
Y-Valve
[0138] In another aspect, MOV technology can be used to create
valves that route fluid from three or more microchannels. In one
embodiment a router can use a microvalve with or without a valve
seat. FIG. 23 illustrates a method of construction of a MOV
microvalve, termed a `Y-valve,` that has three connections. FIG. 23
shows fluids represented by black and a valve seat represented by
the white color. The valve seat may be fabricated by many methods
well known to one skilled in the art comprised of photolithography,
embossing, injection molding, and other microfabrication methods.
When the Y-valve is in the closed position, the valve seat
segregates the three channels that intersect within the valve. When
open, the three channels in this drawing are allowed to communicate
with one another. The volume of the valve chamber increases when
the valve is open and decreases when closed. This change in volume
causes movement in the liquids aiding in the mixing of liquids that
come together in this valve. In the embodiment shown in FIG. 23,
there can be two inlet channels where liquids are brought in and
one outlet channel or one inlet and two outlets.
Flow-Through Valve
[0139] In another aspect a MOV valve as illustrated in FIG. 2 can
be adapted to be a flow-through valve where two or more liquids
come together. The flow-through valve in FIG. 24, termed a
`T-valve,` when closed, as shown in the left panel, allows for
fluid to pass from the top to bottom through the vertical channel
in this example while isolating the horizontal channel. When the
valve is open as shown of the right panel of FIG. 24, fluid can be
moved from the vertical channel to the horizontal or from the
horizontal to the vertical.
[0140] FIG. 25 illustrates the difference between the fluidic
junctions that connects three channels. On the left, a standard MOV
valve is shown to the left of a three way junction. On the right, a
flow-through valve is shown. Both the conventional MOV valve and
flow through valve can be used to regulate flow or as part of a
pump, but the dead volume in the flow through valve is eliminated
where as in the conventional MOV valve, the region from the valve
to the channel intersection is dead volume.
[0141] The number of channels in this type of valve may also vary.
The example illustrated in FIG. 24 shows one channel passing
through and one channel terminating in the valve. In another
embodiment a microstructure may be designed comprising multiple
channels passing fluid through the valve and/or multiple channels
terminating in a closed valve.
Manipulation of Magnetic Beads on Microchips and Other Fluidic
Devices
Star and Nested Star Capture Device
[0142] In another aspect magnetic beads are captured as they move
through a channel structure. In one embodiment magnetic bead
capture is most effective at the edge of a magnetic field. In one
embodiment microchannel structures are designed to take advantage
of this property by passing a channel through the boundary of the
magnet field multiple times. In FIG. 26, the thick lines represent
the channel structures and the thin line represents the magnet. In
this embodiment the capture efficiency of this system depends on a
number of factors including, but not limited to, the sheering force
put on the beads by the fluid passing through the channels and the
force applied by the magnet. In one embodiment only a finite number
of beads can be captured in each channel segment that crosses the
magnet when the flow is high. When the beads are captured in the
channel, they occupy a fixed amount of space, effectively reducing
the channel cross section, and increasing both the fluid velocity
and the sheering force. When this balance is reached and exceeded,
additional beads are pushed farther along the channel to the next
magnetic boundary. Microchannel designs with multiple magnetic
boundary crossings allow for a larger amount of beads to be
captured in the channel as compared to designs with a single
magnetic boundary crossing.
[0143] In some embodiments the magnets may be electromagnetic
magnets or permanent magnets including but not limited to rare
earth magnets, fixed and mobile magnets.
[0144] In one embodiment a microchannel designs with multiple acute
angles can be used to run thermal cycling. In another embodiment
the length of a structure with multiple acute angles can be used
for mixing. When liquids come together in a microfluidic system,
laminar flow can keep liquids separated. A structure with multiple
acute angles and many turns allows for mixing to occur through
diffusion. The circuit on the left panel of FIG. 26 can be
compacted into the nested star shown on the right or many other
configurations. The nested star occupies a smaller space than the
full star.
Capture of Beads by Change in the Cross-Sectional Area of a
Microvalve
[0145] In another aspect the capture of beads can be made more
efficient by changing the geometry of the capture region to
increase the cross section, FIG. 27. The vertical line represents a
channel and the black circle a magnet. As the channel flows through
the magnetic field, the width or depth of the channel can be
increased. The change in cross section captures the beads more
efficiently for a couple of reasons. The increased cross-section
results in a slower velocity as compared to the normal channel
section for a given flow rate. The slower flow means a smaller
force pushing the beads out of the capture region. In addition to
the slower velocity, the added volume gives the fluid a path to
maneuver around beads that are captured in this portion. The
specific geometry can be varied greatly. It can also be used in
conjunction with the star and nested star geometries. This increase
in cross-section can also serve a number of different functions
including a reaction chamber or thermal cycling chamber.
Bead Capture in a Valve
[0146] In another aspect the bead capture in a valve (FIG. 28)
utilizes the same concepts as the capture through the use of an
increase in channel cross-section from the above example. The
microvalve allows for the cross section of the channel to be
changed. When closed, the cross section of the channel remains
uniform throughout. With the valve open, the cross section of the
channel at the valve is increased significantly and in effect the
opening of the valve creates space in the microfluidic channel. As
magnetic particles or paramagnetic particles move through an open
valve, the flow slows down and the magnet can trap the particles.
Closing the valve can release the paramagnetic particles when the
magnetic force is properly balanced. Repeated opening and closing
the valve can be used to remove the paramagnetic particles. The
release can also be affected by passing fluids that interact better
with the beads to increase the drag force or by alternating air and
liquids in boluses.
Reagent Distribution
[0147] In another aspect the interface between the macro world and
microfluidic devices is often times one of the more difficult
problem to solve. While the microfluidic device may use only
volumes as small as nanoliter or picoliter of reagents in an assay,
typically much larger volumes of reagents need to be connected to
the assay device. For a separation device while only nanoliter or
picoliter volumes are injected and processed, the device may need
to access larger volumes of sample in order to load this small
volume. It is also advantageous to minimize the total amount of
reagent in channels to minimize dead volumes.
Common Reagent Reservoir
[0148] In another aspect, a common reagent reservoir is shown in
FIG. 29, where a reservoir in the center supplies two channels. In
this case the minimum volume needed just to fill the bottom of the
reservoir is shared between the two channels, thus the total volume
needed to supply two channels is smaller than that of a design that
has two channels connected to two independent reservoirs. In this
example, each of the two supply channels is further split into two
channels using a y-valve. The y-valve isolated the three channels
that enter it. The isolation helps to reduce contamination
resulting from unwanted flow in the channel that could be caused by
evaporation, capillary forces, or other sources. In this
embodiment, a single unusable volume required to cover the bottom
of a well is shared among 4 channels reducing the total amount of
fluid needed for this system. The number of channels that draw from
a single well or the number of times the channels are split using
an intersection or valve is virtually limitless.
[0149] This system could be used in the opposite direction to
gather waste. In the example shown in FIG. 29, if the flow is
towards the reservoir, four channels could move waste into a single
reservoir. The advantage is fewer waste reservoirs that need to be
emptied. The reservoir can also contain electrodes and connect four
channels to an electrical potential or contain vacuum to pull
materials through the four channels modulated by the y valves or
other valves.
Reagent Delivery System
[0150] In another aspect, a reagent or sample is delivered by
utilizing the flow through valve to minimize the amount of dead
volume at an intersection that allows the channels at the
intersection that can be closed off from one another when desired
(FIG. 30). The benefit of this arrangement is that all of the
reagents in the chain are pumped using a common set of valves.
Using a common set of pumping valves decreases the variation in the
ratio of reagents mixed that would otherwise be introduced by
variations in different pumping valves.
Reagent Loop
[0151] In another aspect, a microstructure comprises three valves
in a reagent loop to act as a micropump to circulate fluid within
the loop and a fourth valve, the flow through valve, allows
additional material to be moved into or out of the loop (FIG. 31).
Multiple flowthrough valves can be used. Using this loop will allow
a user to continuously circulate a minimum volume.
[0152] This system can also be utilized to elute off sample.
Circulating elution solution along with the capture material will
allow more time for the sample to elute off and for the high sample
concentration regions around the capture material to diffuse away
making resulting in an elution of higher concentration.
Integrated Designs
[0153] in another aspect, a system comprising a microstructure is
used to perform chemical and biological reactions. In one
embodiment, for DNA sequencing, forensics and other application,
FIG. 32, the common reagent reservoir is integrated with bead
capture in a valve and a reagent delivery system. Three samples can
be loaded into the sample reservoirs 80. The reagents from the
common reagent reservoir 70s can then be pumped through the check
valve 10 and to the flowthrough valves 20. The pumping can be by
using valves 10, 30, 40, and 50 for example or by using external
pressure with microvalve 10 to modulate the flow. When the
flowthrough valve 20 is opened, the sample from the sample
reservoir 80 is accessed and can be pumped into the flowthrough
stream through microvalve 30 and microvalve 40 into reaction
chamber 60. If thermal cycling is being performed, microvalves 40
and 50 can be closed to isolate the reaction chamber. The reaction
chamber is shown in FIG. 32 as a channel; the reaction chamber can
also be in a valve or moved between valves or channels or other
fluidic components. The movement may be by use of on-device pumping
or by off-device pumping, where in a preferred embodiment the
microvalves may be programmed to direct flow in the desired manner
to enable biochemical reactions to be integrated to produce
reaction (s) which may also be assays. The product or products may
be assayed on the device or moved to another device for assay.
[0154] The device shown in FIG. 32 may then perform a second
reaction. In one embodiment the reaction may be a bead based
reaction that performs biochemical or chemical reactions to further
process the sample. The reaction may be interrogated on the device
or moved to another device for assay.
[0155] In another embodiment, the device is programmed to integrate
multiple steps of reactions for DNA sequencing applications. Common
reagent reservoir 70 is loaded with cycle sequencing reagents which
are mixed with DNA containing samples loaded into sample reservoirs
80 with the samples being in one embodiment PCR, plasmid, or other
nucleic acid amplification products that are to be sequenced. The
mixture containing the sample and cycle sequencing reagents can be
moved by the programmable fluidics using microvalves to a reaction
chamber 60 where cycle sequencing reactions are performed using
thermal cycling. The cycle sequencing products can then be moved to
Product reservoirs 90 for movement off the device for further
processing or in a preferred embodiment the cycle sequencing
products are moved to a reservoir and beads such as Agencourt SPRI
beads are added to the cycle sequencing products with appropriate
chemistry to have the desired cycle sequencing products bound to
the beads to separate the products from the salts and
unincorporated dye labeled terminators or primers which stay in
solution. It is obvious to one skilled in the art that rather than
binding the cycle sequencing products to the beads the reverse can
be performed where the cycle sequencing products are left in
solution and the salts and unincorporated dyes are bound to the
beads. The term bead is used without restriction to include
particles, paramagnetic particles, nanoparticles, gels, gels with
affinity capture property or non-specific properties. If the bead
and cycle sequencing products were contained in reservoir 80 the
combined mixture is pumped through microvalves 20 and 30 to
microvalve 40 which may be opened and have a fixed or movable
magnet in proximity. The beads such as SPRI beads which are
paramagnetic are captured as the flow slows down in the opened
microvalve and the beads are captured in the magnetic field. Fluids
such as ethanol may be added to reservoirs to then process the
beads and remove the undesired impurities such as salts and
unincorporated dye labeled reactants. The beads may be then pumped
to product reservoirs 90. For cycle sequencing the products are
ready to be analyzed on a separate device such as a CAE or
microchip with separation. It is obvious to one skilled in the art
that the different reservoirs may have other configurations and a
single sample can be added to reservoirs 70 and multiple reagents
may be added to reservoirs 80 to perform three different reactions
on a single sample.
[0156] In another embodiment, the device is used for sequencing by
ligation or sequencing by synthesis. Beads may be held in a
configuration that they may be interrogated by a detector using
laser induced fluorescence, Raman, Plasmon resonance or other
methods. In this embodiment the bead may be held in a reaction
chamber 32 and the reactants moved by micropumps past the beads
where fluorescently labeled reactions occur and are read out with
the detector. The reactants can then be removed by pumping other
fluids to wash the beads to remove the reactants such as
pyrosequencing, sequencing by synthesis, sequencing by ligation or
other sequencing chemistries. The next reagent may then be added
using either on device micropumps to move the reagents or using
microvalves to modulate the flow of reagents to perform the next
round of sequencing. The beads may be held by magnetics, optical
trapping, or other energy methods or by physical constraint such by
trapping in weir structures. (U.S. Pat. No. 7,312,611, which is
herein incorporated by reference in its entirety). In one
embodiment a microstructure comprises an on-chip packed reactor bed
design using one or more weir structures that allow for an
effective exchange or trapping of beads at a miniaturized level. In
one embodiment each bead may perform a reaction or as currently
used with pyrosequencing some beads may have additional
reactants.
[0157] In another embodiment, the beads may be held and some beads
intentionally not perform reactions to allow improvement in the
detection. The improvement is gained by optically isolating the
signal from a bead that has the DNA sample to be interrogated by
physically separating beads with signal from other beads by
physical dilution of the desired signal. This will improve the
signal to noise of the reactions by allowing the control of the
signal from other beads and enables the manipulation of crosstalk
in channel or chamber. For example if a 100 beads of the same size
that do not have DNA sample to be sequenced are added to per bead
with DNA then there would be one signal every 100 beads which would
improve crosstalk. Other dilutions are also possible.
[0158] In another embodiment (FIG. 33), the elements of a common
reagent reservoir 70, sample reservoir 80 and product reservoirs 90
and microvalves 10, 20, 30, and 40 are rearranged to use the star
capture to produce a device that can perform a reaction and then
clean up the reaction products using magnetic or other beads or
other purification methods. FIG. 33 shows a different design than
FIG. 32 that also can perform DNA sequencing. Samples can be added
to reservoirs 180 and cycle sequencing reagents to reservoirs 170,
mixed through microvalves 110, 115, 120, and 130 and moved into
chambers 160 for cycle sequencing or other reactions. Reservoir 185
can be used to add beads to reaction products which are then moved
to star capture circuit 140 for magnetic capture. Washed can be
performed by adding different solutions such as for SPRI chemistry,
or other bead based chemistries to move the solutions past the
entrapped beads to remove the undesired products such as salts or
unincorporated dyes.
[0159] In another embodiment, an integrated design is capable of
running a variety of processes. It can accurately mix together two
reagents, run a reaction on the mixture, and clean up the product
of this reaction. Because this system has active pumping of fluid
between two of the reservoirs, addition reagents can be supplied to
the reaction. This design is very compact and has the advantages of
using less space per circuit, being able to be packed into a
microchip such that a portion can be diced off to improve microchip
yield, and performance improvements.
[0160] In another embodiment, FIGS. 32 and 33 illustrate the
coupling of biochemical and chemical reactions as described for
cycle sequencing and chemical reactions such as SPRI cleanup. It is
obvious to one skilled in the art that different biochemical and
chemical reactions may be integrated by using microvalves on
devices. For forensics, short tandem repeat (STR) reactions can be
performed on a device incorporating programmable microvalves by
using STR reactions such as PowerPlex 16 to amplify DNA and a bead
cleanup to purify the reaction.
[0161] In vitro transcription reaction, translation reactions or
coupled transcription and translation reactions may be performed in
the programmable microfluidic circuits to assay DNA, or RNA
respectively. This may be used to assay the effects of additional
materials added such as microRNAs, inhibitors, drug candidates,
chemicals, or other materials to be assayed. This may be employed
as a screen for the impact of the added material on the
transcription, translation, or coupled transcription and
translation reactions. In one embodiment the coupled transcription
and translation reactions produce energy harvesting products. In
another embodiment a detector 105 is added to monitor reactions in
the programmable microfluidic circuit.
[0162] The designs shown in FIGS. 32 and 33 are shown in a
rectilinear design but it will be evident to one skilled in the art
that other designs such as a radial design may be used. ("Roach,
D., R. Loder, T. Armstrong, D. Harris, S. Jovanovich and R.
Johnston. Robotic microchannel bioanalytical instrument. Sep. 30
2003. U.S. Pat. No. 6,627,446"; "Roach, D., R. Loder, T. Armstrong,
D. Harris, S. Jovanovich and R. Johnston. Robotic microchannel
bioanalytical instrument. Jul. 20, 2004. U.S. Pat. No. 6,764,648",
"Roach, D., R. Loder, T. Armstrong, D. Harris, S. Jovanovich and R.
Johnston. Apparatus and Method for Filling and Cleaning Channels
and Inlet Ports in Microchips Used for Biological Analysis. Sep. 7,
2004. U.S. Pat. No. 6,787,111." all of which are herein
incorporated by reference, in their entirety). In one embodiment,
the microvalves may perform reactions using chemical or biochemical
processes to process materials to produce a product or products
from a sample. The product is comprised of chemical or biochemical
composition and may produce energy, store energy, or use patterns
of storage to transform energy in controlled manners.
[0163] The integration of chemical or biochemical processes is
disclosed on how to produce products or assay components either in
the reaction or material added to the reaction to assay some
property of the material. The term material is used without
limitation and may mean matter or energy where in one embodiment
the reaction is assayed by the production of light comprised of
fluorescence, luminescence, or other alterations of the
electromagnetic spectrum. In one example the programmable
microfluidic circuit may perform reactions that are interrogated by
a detector such as laser induced fluorescence detector for nucleic
acids such by real time PCR, mass spectroscopy or other means well
known to one skilled in the art or for proteins by reactions that
can be assayed for chemical or biochemical transformations that are
catalyzed by the reactants. In one embodiment the device may store
energy in bulk or in patterns using chemicals or biochemicals to
store the energy in a useful manner such as for visual or optical
or manners. The device may be passive or programmable to alter its
behavior. This may be employed to alter its signal production in
manners that change the optical properties or other properties by
chemical or biochemical transformations. This may be used to be a
sensor of conditions, a reporter to identify physical objects,
transform matter and energy.
[0164] The reservoirs may be used to connect the programmable
microfluidic circuits to other upstream or downstream devices. A
robot may be used to pipette or transfer fluids or modular
microfluidic connections may directly connect to other microfluidic
devices.
Microfluidic Chip Assembly Method--Thermally Bonded Membrane
[0165] In one aspect, a microfluidic chip (microchip) is built from
two layers of glass or plastic joined by thermal bonding. Some
medical test strips are built from using adhesive (typically in the
form of a tape) to join plastic layers with channels and other
features cut into one or more plastic and/or adhesive layers.
[0166] In one embodiment, programmable microfluidic circuits can be
made from features that include MOV microvalves and related
features in the chip. (Hereafter, we use "valves" to mean any of
this family of features.) In the embodiment shown in FIG. 2, a
stack is used with two layers of bonded glass with etched
microfluidic channels and drilled holes, a layer of PDMS for the
membrane, and a layer of glass into which pneumatic channels are
etched to provide actuation pressures to the diaphragms. In this
construction, the PDMS is moderately self-adhesive to the glass but
can be locally separated from it in the valves and treated to
reduce adherence in the valves. Three layer structures are also
possible.
[0167] In one embodiment, pneumatically actuated microvalves are
manufactured in plastic materials. As the material is changed
plastic materials for the microfluidic and pneumatic layers, a PDMS
membrane no longer has sufficient adherence to use the same
construction as with glass and a new method must be developed.
[0168] In one embodiment, all-plastic chips have been assembled
using heat and pressure to thermally bond a microfluidics layer, a
membrane, and a pneumatics layer simultaneously. This process
requires careful control to ensure that the layers bond strongly
except in the valve area in which the lack of pressure prevents
bonding of the membrane to the microfluidics layer--if the time,
temperature, and pressure are right. It can be challenging to
achieve uniform bonding over an entire chip and not bond in the
microvalve.
[0169] FIG. 34 illustrates an example of a hybrid plastic
microchip. In another embodiment of the invention, the membrane is
thermally bonded to the microfluidics layer using one or more of
several methods. Each of the methods avoids bonding the membrane in
the valves by keeping its temperature there below the bonding
temperature while the rest of it is heated and pressed onto the
microfluidics layer. One factor aiding this approach is that the
membrane can be made quite thin (e.g., 25 microns) while a typical
valve might be 1 to 3 mm in diameter. This enables the use of an
approach where the heat is applied to a heating plate that has
areas removed in a pattern that matches the valve pattern. To get
to the center of the valve from the sides, the heat for bonding
must travel 20 or more times the distance it must go to reach the
interface between the membrane and microfluidics layers. This makes
it possible to heat the bonding area while keeping the valve area
cool enough that it does not bond. The relevant areas of the valve
seat that should not be bonded can also be surface modified by
coating, including using photolithography masking, subtractive
etch, chemical vapor deposition, and other methods well known to
one skilled in the art. The relevant areas of the valve seat that
should not be bonded can also be maintained at a different
temperature by localized cooling or the assembly that heats the
microfluidic and membrane layers can have regions removed at the
valves such that the local area at each valve will receive less
heat and thereby not reach its Tg and not bond.
[0170] In one embodiment, a membrane is attached to a microfluidics
layer by a method comprising of (1) using a heated plate or roller
with a profile cut into it so that it contacts the chip components
only in areas where bonding is desired, typically everywhere except
in the valve areas; (2) Using a laser to selectively heat the
desired areas. In this approach it may be desirable for one of the
layers to be transparent to the laser wavelength while the other is
opaque to it. In this way, the laser energy is absorbed at the
interface between the materials where we most want it. An
additional stiff but transparent layer should be used to apply
pressure to the interface. Alternatively, the "Clearweld" method
can be used. In that method, the interface is painted with a
special compound designed to absorb a laser wavelength that passes
easily through the chip layers which can all be transparent; (3)
using a high power IR source and a mask to shade the areas where
bonding is not desired. Only the exposed areas would be heated; (4)
Ultrasonic welding. Depending on the materials used, these heating
methods may optionally be enhanced by selectively exposing the
surfaces to be bonded (or not be bonded) to UV light and/or plasma
to modify their bonding temperatures.
[0171] In another embodiment, pneumatic actuation can be built into
a instrument that uses a microchip and the microchip is held
against the instrument in a position to allow actuation of the
valve membranes. There is great flexibility with this approach in
how to make and attach the pneumatics layer. Some embodiments are
(1) Cut the pneumatics channels through a transfer tape or
double-sided tape (e.g. by laser-cutting or die cutting) and adhere
the tape to a cover film and then adhere this assembly onto the
microfluidics/membrane assembly or adhere the tape to the
microfluidics/membrane assembly first and then add the cover; (2)
Mill, engrave, or mold a plastic pneumatics piece so the channels
don't go all the way through. Use a liquid adhesive to bond it to
the microfluidics/membrane assembly; (3) Mill or engrave the
pneumatics pattern through the adhesive side of a tape. (4) Use
mechanical clamping to hold the microfluidics/membrane assembly
against the pneumatics assembly. In this case, the pneumatics could
be part of the chip or part of the instrument as desired; (5)
thermally bond a pneumatics piece onto the microfluidics/membrane
assembly. Note, can choose a lower-melting material for the
pneumatics to avoid damaging the microfluidics/membrane
assembly.
[0172] In one example a means to make plastic microfluidic chips is
provided. Materials can be chosen so that a sample is exposed to
only one material. If a supporting plate is at a cool temperature,
then the microfluidics layer can stay cool during the bonding
process, avoiding shrinkage. There is a choice of methods for
generating the required heat. There is great flexibility in
choosing materials and attachment methods for the pneumatics
layer(s). It is inexpensive. It does not require significant new
technology to be developed. It ensures good bonds along the
microfluidics channels, even where pneumatic channels cross them.
In the existing three-layer simultaneous bonding method, there is a
chance that lack of pressure at these locations would prevent good
bonding resulting in a leaky channel.
Mechanically Clamped Microchip
[0173] In another aspect a microfluidic chip is manufactured by
mechanical bonding of the and/or layer to allow for seals to be
made between parts that would otherwise not be joined.
[0174] In one embodiment (FIG. 35), a mechanically clamped chip
allows for the use of a wide variety of membrane layers without the
need to find bonding techniques for the variety of materials. This
example contains layers that have different property requirements.
The microfluidic and pneumatic layers both require the ability to
hold small features, the membrane layer needs operate as a MOV
valve, and the membrane and microfluidic layers must be compatible
with the chemical or biological assays. The mechanical clamping
makes the construction of such a part possible without the
introduction of additional materials such as adhesives. The
different layers are aligned and mechanically clamped together.
FIG. 36 show a picture of a chip made in this manner.
Clamped Chip that Reduces Alignment Requirement
[0175] In this embodiment (FIG. 37), the fine features that need to
be aligned are contained in two layers: the pneumatic layer and the
microfluidic and valve layer. The features in microfluidic layer
can be bonded by many methods to the sealing layer since both can
be made of the same material. Features such as ridges and channels
can be placed on the microfluidic and pneumatics layers to aid in
sealing to the membrane layer. The pneumatics layer is mechanically
clamped with the membrane to the assembled microfluidic and valve
layer. The reduced area that needs to be clamped in this design
reduces the tolerance stack and simplifies the manufacturing of the
microchip.
Adhesive Laminated Microfluidic Chips
[0176] In another aspect a laminated microchip is disclosed. MOV
microfluidic chips typically contain diaphragm valves and related
features, such as pumps, routers, and variable volume chambers
(hereafter, we use "valves" to mean any feature of this family), so
far using glass for the rigid layers and PDMS for the diaphragm's
membrane. Glass to glass interfaces are thermally bonded and the
membrane's inherent properties provide sufficient adhesion to join
it to the glass without an adhesive.
[0177] For many applications, it would be desirable to replace
glass with plastic to lower the cost of the microfluidic chips.
PDMS does not have sufficient inherent adhesion to plastics tried
so far to withstand the pressures used in operating the valves.
Further, the permeability of PDMS to gases can allow bubbles to
form in valves that are held closed. Such bubbles can be
detrimental to the performance of the chip.
[0178] In some embodiments adhesives are used to join layers to
make microfluidic chips (U.S. Pat. No. 6,803,019 and U.S. Pat. No.
6,176,962, which are herein incorporated by reference, in their
entirety)
[0179] In one embodiment, the various layers of a microfluidic chip
are joined using adhesives, and in some embodiments, features such
as channels are formed in some or all of the adhesive layers. A key
difference from other work in adhesive-laminated microfluidic
structures is the inclusion of valve features and related
structures. Two examples of embodiments of the concept are shown in
FIG. 38 and FIG. 39. In the first embodiment in FIG. 38, the
microfluidic layer, interface layer, and pneumatics layer are made
of transfer tape which has had appropriate channels and holes cut
through them, e.g., by laser cutting. The other layers are made in
thin plastic sheets which also have appropriate features cut
through them. Thus multiple layers can be made of transfer
tape.
[0180] In another embodiment, FIG. 39, a microchip is constructed
by etching the channels in a glass wafer and thermally bonding it
to a glass via layer and using two adhesives to assemble in a
different order. Thus manner arrangements are enabled by using
multiple adhesive layers which may be transfer tape. The
microfluidic layer could have been thermally bonded plastic or
fabricated in other materials, with other shaping methods, and/or
other joining methods.
[0181] In another embodiment, FIG. 40 illustrates a close-up view
of a valve constructed by adhesive lamination. When pressure is
applied to the valve chamber via channels in the pneumatics layer,
the membrane is deformed until it presses against the two vias,
sealing them which prevent fluids in one of the microfluidic
channels from passing through the valve to the other channel.
Vacuum applied to the valve chamber pulls the membrane away from
the via openings allowing flow from one microfluidic channel to the
other.
[0182] In another embodiment, an adhesive lamination method allows
for great flexibility in design. There are few limits on what can
be integrated into the design. For example, FIG. 41 illustrates an
adhesive laminated chip with heaters and heat spreaders built in.
Different embodiments add electrodes, optical components, other
temperature control components such as heat pipes or heat sinks,
sensors, printed markings. Since no heating or only moderate
heating is needed to cure the adhesives, these types of additions
can be made without damage to them, though they must withstand or
be protected from the pressures used in the laminating process.
[0183] Adhesive lamination construction is an inexpensive way to
create microfluidic chips. There is great flexibility in the choice
of materials Films and transfer tapes of many varieties are readily
available off-the-shelf. The chip can be kept quite thin which can
be useful for thermal control. If thin enough, it can be flexible
enough to be stored in roll form. Features in each layer can be
laser-cut, waterjet-cut, or die-cut as needed. These are all fast
and flexible methods so prototyping and low volume production can
be accomplished quickly. Design changes can be made with short lead
time. The necessary technology to implement the method exists and
there are multiple vendors capable of supplying the assembly. Mass
production can be achieved quickly. Hybrid constructions in which
one or more layers are made by different techniques are easily
implemented. If desired, the interface adhesive can be made
relatively thick to form a normally fully open valve. Such a valve
does not require a vacuum source. It could be closed with pressure
and the valve would open when the pressure is removed and the
membrane returns to its minimal stress position (flat). Additional
functionality can be incorporated easily, such as the incorporation
of heaters, heat spreaders, optical components, etc.
Valve Arrays Integrated on Plastic Microfluidic Devices
[0184] In one aspect of the instant invention, three layers of same
plastic material are laminated for obtaining the microfluidic chip.
One embodiment is shown in FIG. 42. The bonding parameters for same
plastic material are temperature and pressure. In the right
conditions, the membrane will be permanently bonded to both top
(microfluidic) and bottom (actuation) plates, except for the area
above the valve chamber, where pressure conditions are different so
the plastic membrane will move down if vacuum is applied in the
valve chamber or up if pressure is applied. Pressure conditions are
different in the area at the valve since it is not in contact with
the bottom actuation layer due to the valve chamber it will
experience less pressure during lamination or in a press. When a
constant temperature is applied to the whole device or assembly,
the pressure will be less on the materials contacting at the valve
which will prevent bonding when the temperature is adjusted so
bonding occurs only when pressure is transferred to the membrane.
This is a normally closed valve. In another embodiment, a normally
open valve can be made by adjusting a higher pressure in the
microfluidic channels than in valve chamber during the lamination.
A depressed membrane will be obtained after device cooling in FIG.
43. Only pressure is needed for actuation this valve. Pressure is
available without electrical energy and this valve may be valuable
for portable instruments. For these three layer structures, air
channels can't cross more than two microfluidic channels and vice
versa, because the membrane will not be bonded under the channels
(no pressure there). This can be an impediment for ganging valves
in a multi-channel device.
[0185] In another embodiment the intersecting air and microfluidic
channels can be used with a four layer structure. FIG. 44 shows a
cross-section of this structure. This valve is normally closed and
it needs pressure and vacuum for actuation. The normally open
version can be also produced, with pressure-only actuation.
[0186] In another embodiment a patternable material that can be
selectively deposited on the valve seats and then removed after the
bonding is completed, such as photoresist, like Shipley 1818,
screen printing of water soluble polymers, light activated
compounds such as UV activated polyacrylamide (ReproGel, GE
Healthcare), that are compatible with the bonding temperature. An
alternative embodiment modifies the surface properties of some
areas by changing the melting temperature of the modified region
for example by UV activation of plastics such as polycarbonate at
areas where selective bonding is needed. In another embodiment,
bonding of the membrane to the valve seat is disrupted by passage
of liquids such as acetonitrile, preferentially viscous liquids
comprising polyethylene glycol and propanediol.
Linear Array of Valves for Bead Cleanup in a Plastic Microchip
[0187] In another aspect, a linear array of valves was designed for
a bead clean-up protocol. For example, FIG. 45 shows a mask design
on the top panel and the picture of an acrylic 3 layer this chip in
the bottom panel. A device was made from two 1.5 mm thick acrylic
plates and a 0.04 mm acrylic film Microfluidic channels (blue) and
actuation channels (red) were milled (0.25 mm wide and 0.1 mm deep)
in each one of 1.5 mm plates respectively. Access holes were
drilled in both acrylic plates. A special channel for junction
temperature control was cut into one plate. The acrylic sandwich
was aligned and placed on a planarizing chuck, covered with a glass
plate and placed in a press with heated plates. The lamination was
done at 100.degree. C. and 1 ton pressure force. The chip was
tested for continuous pumping for 3 days. No pump failure was
observed.
[0188] In FIG. 46, the design and the picture of a three layer
acrylic chip for forensic protocols is presented. The chip will mix
sample with bead solution, use bead sample concentration in the big
valves, mix cleaned sample with PCR reagents, perform PCR
amplification and post-PCR clean-up. The chip dimensions are 30
mm.times.30 mm. The channels are 0.25 mm wide and 0.15 mm deep. The
amplification channel can hold about 1.5 .mu.L. The microchip works
as follows. Pneumatic line 211 actuates microvalves 210 and 220.
Pneumatic line 212 actuates microvalve 215. Pneumatic line 213
actuates microvalves 250 and 255. Pneumatic line 214 actuates
microvalve 276. Pneumatic line 216 actuates microvalve 240.
Pneumatic line 217 actuates microvalve 230. Pneumatic line 219
actuates microvalve 246. The sample which has material attached to
paramagnetic beads is loaded into reservoir 280 which is connected
to microvalve 220. Pumping by microvalves 220, 230, and 245 can
move the sample into microvalve 240 which is opened and has a
magnetic field to trap beads. The beads are washed using wash
buffer loaded into reservoir 275 controlled by microvalve 276 with
pumping by microvalves 276, 230, and 245 with the wash going to
waste 247. Reservoir 275 can then be filled with eluent and the
purified samples from the beads eluted into buffer compatible with
downstream processes and pumped through microvalve 246. At
microvalve 255, reaction mixtures is added from reservoir 270 using
microvalves 210, 215, and 255 to mix as taught with the eluted
sample as it flows into reactor 260. Valves 250 and 255 can be
closed if a thermal cycling process is being performed such as PCR
or cycle sequencing. Following the reaction, the sample is pumped
out to reservoir 290
[0189] These examples were designed for various sample preparation
protocols like sample concentration, thermocycling (for cycle
sequencing or PCR reactions), isothermal reactions, and sample
purification. The plastic multi-layer lamination can provide low
cost and disposable complex chips with valves and pumps These
disposable chips are required in many application fields like
forensics and molecular diagnostics. A disposable chip can make the
instrument much simpler without preparations and cleaning steps.
The use of normally open valves will not require a vacuum pump or a
pressure pump. The actuation pressure can be provided by a
pressurized cartridge and the whole apparatus power requirements
can be acceptably low.
Rapid Movement of Fluids and Reactions in Valves
[0190] In another aspect a microstructure rapidly moves a fluid
between two or more different spatial locations. There have been a
number of approaches to performing thermocycling of reactions for
PCR, cycle sequencing, and other purposes. These may generally be
placed into two classes. In the first, the reaction components are
located in a chamber whose temperature is varied with time. In the
second, constant temperatures are maintained in two or more
locations and the reaction components are moved from
location-to-location and come to equilibrium with the temperature
at each location. We may call these "temporal" and "spatial"
cycling, respectively.
[0191] When performed in microfluidic applications to date, those
using spatial cycling generally provide a fluid channel which
meanders through the temperature zones, and they force the reaction
fluids through this channel unidirectionally, usually at a constant
speed. Flow is normally generated by application of pressure
generated by devices external to the microfluidic structures.
[0192] In one embodiment, thermocycling is accomplished by moving
the reaction components between or among zones of different
temperatures in discrete steps by means of one or more pumps. The
pumps could be external, but in the preferred embodiments, the
pumps are internal to a microfluidic chip in which the reaction
components are thermocycled. One embodiment is shown in FIG. 47. In
this approach, one of our MOV pumps is used to move the sample
between a hot zone and a cool zone. For simplicity this diagram
illustrates only a two-temperature system. But the invention is not
limited this way and it is easy to expand the idea for three or
more temperatures.
[0193] For example, FIG. 48 shows a way to implement
three-temperature cycling. Here an on-chip pump is used to move the
sample through three temperature zones. In this case, the
temperature zones extend over different volumes of the channels.
With constant speed pumping, the sample would be exposed to each
temperature for a time proportional to the volume of the channel in
each zone. With the on-chip pumping, it would be easy to move the
sample in discrete moves instead. In this way, the temperature
zones could be made smaller, just big enough to contain the sample.
Then the pump would only be actuated for a short period to move the
sample from one zone to the next and the dwell at each temperature
would be determined by the time between pump actuations. This gives
flexibility for adjusting the temperature cycling profile without
redesigning the channels or heaters. Note that the sample can be
surrounded by an immiscible fluid to keep it from diffusing. Thus
boluses and microemulsions are enabled by this programmable
microfluidic circuit and the boluses and microemulsions can be
assayed with a detector to perform real time reactions or endpoint
reactions, for example, real time PCR in boluses or microemulsions.
For a higher throughput system, it may be desirable to use a
pipeline construction as shown in FIG. 50.
[0194] In FIG. 49, an alternative embodiment is shown in which the
sample is moved between hot and cool zones without passing through
a pump, eliminating interactions with the materials in the pump and
loss of sample to dead volumes. Again, an immiscible fluid can be
used on either size of the sample to help keep it from diffusing.
It is not necessary to have two complete, three-chamber pumps as
shown here.
[0195] If re-use of these features is needed, it may be necessary
to wash or rinse them before re-use to prevent cross-contamination.
Additional features may be added for these functions to clean the
chambers as shown in FIG. 51 for a segment of a reactor.
[0196] In another embodiment, the temperature zones are located at
the same positions as valves as shown in FIG. 52 for
two-temperature cycling and in FIG. 53 or three-temperature
cycling. In this embodiment, the bulk of the reaction components
can be transferred from one zone to another by closing the valve
containing them while simultaneously opening the valve in the
destination temperature zone. A portion of the reaction components
will be left in the channel and thus not reach the intended
temperatures which is undesirable. But by appropriately sizing the
valves and channels, this fraction can be kept small. An advantage
of this embodiment is that there is no possibility of the sample
moving too much or too little and thus not being properly
positioned in the temperature zone. The reactions in the valves can
be in three layer microvalves where the elastomer or valve membrane
is deformed to create a space or in a four layer microvalve where
the reaction is performed in the via.
[0197] In FIG. 54, an alternative embodiment for three-chamber
cycling is shown. In this implementation, the liquid is pumped with
a circular rotation. That ensures that none of the sample stays in
the channel repeatedly, but increases the channel volume relative
to the valve volumes.
[0198] In some embodiments it is unnecessary for the valves in the
temperature zones to actually make a seal. Only the volume changes
as the valves are opened and closed is important. One option this
allows is to leave out the valve seats so that the channel allows
continuous flow through the thermocycling area. This has an
advantage during the initial filling of the chip and movement of
the reaction components into the thermocycling area. During
filling, all but one of the valves can be left closed using the
least necessary volume of reagents. If the valves have seats, they
must be open to allow filling. If the chip is filled until the
reaction components are seen to reach the far end of the
thermocycling area.
[0199] In some embodiments, it is desirable perform thermocycling
in a device that has one or more of the following characteristics:
rapid temperature transitions; stable, accurate temperatures;
small, lightweight package; disposable reaction container; small
reaction volumes; low power requirements; automated mixing of
sample and reagents; programmable control of temperature profile
(temperatures and times); configurable for a range of sample sizes
(nanoliters and up); configurable for a range of numbers of samples
(from 1 per device to hundreds or more); low operating cost; low
pressure requirements to move reaction components through the
device.
[0200] In one embodiment a microstructure thermocyler is mobile or
handheld. In another embodiment the microstructure thermocyler is
not battery powered. In one embodiment a fixed zone heating
approach is used to keep power requirements acceptably low and
micropumps are used to move fluids between temperature zones. In
another embodiment microvalves are used to control fluids
comprising analytes, particles, nanoparticles, emulsions,
microemulsions, reagents and combinations thereof.
Reactions in Microchips and their Use in Library Construction and
Analysis
[0201] Traditional Sanger shotgun sequencing has involved
laborious, expensive, and time consuming in vivo cloning,
selection, colony isolation, and amplification steps. The large
genome centers have automated many of these processes with islands
of robotic automation. Next generation technologies now under
development or in early stage deployment by companies such as ABI,
Solexa, and 454 may offer radically lower cost sequencing by
performing reactions on small ensembles of molecules. At the same
time, these technologies and others such as SuperPyroSequencing and
single molecule sequencing--will vastly change sample preparation
requirements and methods.
[0202] The 454 Corporation has now developed pyrosequencing in a
miniaturized format with picoliters reactions on individual beads
in a "Picotiter plate" with shotgun template generation by emulsion
phase PCR (Margulies M, et al. Genome sequencing in microfabricated
high-density picoliter reactors. Nature, 2005 Sep. 15;
437(7057):376-80. Epub 2005 Jul. 31.). Each four hour run generates
about 25 M bases per run of sequence with average readlengths of
about 108. The sample preparation procedure to support each run is
complex with many manual steps. DNA adaptors are added to sheared
DNA libraries, single-stranded DNA purified, and DNA amplified from
single molecules on beads by emulsion PCR (emPCR). Emulsion PCR has
the ability to generate millions to billions of separate
compartments in a single tube using a conventional thermal cycler.
Dressman et al. have produced clonal PCR amplicons attached to
magnetic particles using emulsion PCR (Dressman D, Yan H, Traverso
G, Kinzler K W, Vogelstein B. Transforming single DNA molecules
into fluorescent magnetic particles for detection and enumeration
of genetic variations. Proc Natl Acad Sci USA. 2003 Jul. 22;
100(15):8817-22. Epub 2003 Jul. 11.) and (Diehl F, Li M, He Y,
Kinzler K W, Vogelstein B, Dressman D. BEAMing: single-molecule PCR
on microparticles in water-in-oil emulsions. Nat Methods. 2006
July; 3(7):551-9.) and procedures for amplification of complex
libraries have been developed (Williams R, Peisajovich S G, Miller
O J, Magdassi S, Tawfik D S, Griffiths A D. Amplification of
complex gene libraries by emulsion PCR. Nat Methods. 2006 July;
3(7):545-5). The process to produce the clonal libraries on beads
takes about two days, with a number of manipulations with
specialized equipment, and produces beads of about 375 bp. The
sample preparation has become a major rate limiting step for the
G20 throughput. It will not be possible to generate the over
100-fold increase in bead production to sequence a human genome per
day without full automation. To extend the 454 sample preparation
to de novo sequencing mammals and other complex genomes require a
rapid hierarchical cloning strategy and the processing of hundreds
of thousands of libraries per day. The same sample preparation can
be applied to SOLiD sequencing by ligation
[0203] In one aspect, miniaturized sample preparation is used to
automate library processing into bead libraries through the use of
microfabricated structures, microfluidics, and magnetic separation
combined with improved emPCR. Massively parallel bead libraries,
which are required to enable the automated hierarchal sequencing
approach, can be constructed. For example, 4,032 individual
libraries can be created every 45 min with each single, clonal
microsphere carrying sufficient DNA template for pyrosequencing. In
some embodiments devices are constructed with from one channel to
hundreds of thousands of microchannels capable of processing up to
a million individual sequences.
[0204] While the examples describe DNA pyrosequencing, the DNA
analysis methods can be other reactions such as sequencing by
synthesis such as by Solexa, Helicos, ligation reactions such as
Agencourt/Applied Biosystems to sequence, and other DNA analysis
methods.
[0205] In addition to creating libraries for DNA sequencing, the
same approach can be made to make DNA libraries or samples for
other DNA analyzes, RNA analysis, proteins, carbohydrates, lipids,
and other biomolecules. These include samples that were produced by
programming in vitro DNA-RNA-protein systems, such as coupled
transcription-translation systems, systems that perform
modifications to biomolecules, and products from those systems.
Similarly, the approach can be extended to chemical libraries and
synthesized biomolecules libraries.
[0206] The approach can also be used to implement molecular biology
reactions in devices such as microchips.
[0207] In the following examples, ligation is used in many of the
examples. In addition to ligation reactions, one skilled in the art
can readily see that all biochemical and chemical reaction can be
performed, e.g., restriction, DNA modification, polymerization,
DNA-protein binding, and other biochemical reactions, as well as
additions, cleavages, cyclicization, condensations, and other
chemical reactions.
Automated Bead Based Cloning and Amplification in Fluidic Systems
for Microbead-Based In Vitro Emulsion Phase PCR Library
Construction
[0208] In one aspect, bead-based cloning and amplification methods
and instrumentation can be based upon an automated instrument, to
rapidly process large numbers of sequences. For example, 128,000
input BAC or other libraries can be processed into 250,000,000
beads ready for SuperPyroSequencing (SPS) of a human-sized genome
every day. FIG. 55 illustrates a high level depiction of the
workflow and processes. The term SuperPyroSequencing is used to
describe readout of the beads produced in the NanoBioPrepSPS where
the beads contain a DNA library made from single copies of
templates. In other implementations a different chemistry can be
applied to additional workflows to perform Real Time PCR in
boluses, emulsions, and microemulsions. Other biochemistries are
also possible as described in this instant invention. The
NanoBioPrepSPS' platform is one example of combining bead based
chemistries for sample preparation for a DNA sequencing
implementation. In some embodiments gene expression, protein
expression, and other implementations can be adapted to bead based
reactions, and reactions in fluidics (U.S. Pat. No. 6,190,616; U.S.
Pat. No. 6,423,536; U.S. application Ser. No. 09/770,412; U.S. Pat.
No. 6,870,185; U.S. application Ser. No. 10/125,045; U.S.
application Ser. No. 11/229,065; all of which are herein
incorporated by reference in their entirety). In some embodiments
boluses of samples in an immiscible fluid or microemulsions are
analyzed, such as in the SuperPyroSequencing example. This is
another example in this invention that teaches how to couple
biochemical and chemical processes and perform multiple reaction
steps with microfluidic devices. It is clear to one skilled in the
art that modular microfluidic connections can enable moving samples
produced as described herein.
[0209] In one embodiment the NanoBioPrepSPS could input 4,023
end-polished libraries per 45 min and in a Ligation Module perform
4,023 nanoscale individual ligations of keyed adaptors on 42
microchips, each with 96 channels. The Ligation Module then pools
the libraries and bind single fragments onto single beads. The
emPCR Module uses emulsion phase PCR (emPCR) to create a bead-based
DNA library for SuperPyroSequencing.
[0210] In one embodiment, a single channel microchip can perform
the ligations and commence development of scalable hardware,
microchips, and software to fully automate the microchip portion of
the Ligation Module. A `BeadStorm` device as described below, can
resuspend, mix, process, bind, and move magnetic and non-magnetic
beads. For the emPCR process, hardware to accommodate up to and
over 100 mL emPCR reactions and other parts of the workflow is
disclosed for a single emPCR channel; other implementation can use
additional channels which are within the scope of the present
invention. A robust full scale procedure is may be used to produce
high quality beads libraries.
[0211] In one embodiment, the NanoBioPrep SuperPyroSequencing
(NanoBioPrepSPS) process (FIG. 55) automates library processing to
ligate adaptors, construct a single-stranded DNA library, and
perform emulsion phase PCR (emPCR) to produce beads, plastic,
polystyrene, glass or other beads, with clonal populations of DNA
fragments derived from Bacterial Artificial Chromosomes (BACs),
BAC-equivalent libraries, reverse transcription products, single
samples, whole genome amplification, pooled samples such as
environmental samples including aerosol collectors for monitoring
including biodefense applications (collectively termed libraries).
The final products, a DNA bead library, supply a
SuperPyroSequencing readout instrument to collect complete de novo
mammalian-scale genome sequencing in a single day.
[0212] In this example, the NanoBioPrepSPS process inputs 4,032
individual libraries per run, which have been pre-sheared to a
population centered around 1,000 base pairs undergone end-polishing
and phosphorylation, from 101/2 384 well microtiter plates every 45
min. The NanoBioPrepSPS will thus process 128,000 libraries per
day, generating up to 250,000,000 beads. The amounts of beads
generated will be tunable. Each bead will harbor amplicons of up to
1,000 bp, sufficient to produce 60 B bases of sequence data per
day--a human-sized genome at 10.times. coverage in a single day.
The NanoBioPrepSPS instrument example teaches effective and
efficient means of front-end sample preparation to produce shotgun
libraries ready for SuperPyroSequencing for de novo and
re-sequencing modalities as well as other microbead and
microemulsion processes which can be combined with the biochemical
and chemical processes enabled in this instant invention.
[0213] In another embodiment, the NanoBioPrepSPS instrument
integrates two modules as shown in FIG. 55. The Ligation Module
inputs the fragmented, sized, and end-polished, libraries (1) binds
unique adaptors to the ends of the fragments, (2) repairs 3' nicks
resulting from the ligation reactions, and (3) denatures to
generate single-stranded (SS) DNA libraries for input into the
second module, the emulsion PCR (emPCR) Module. The emPCR Module
(1) anneals the SS libraries onto beads using bound capture primers
under conditions whereby a single DNA molecule will bind to a
single bead, (2) performs emPCR to amplify DNA on the beads, (3)
denatures the double stranded DNA to produce glass beads covered
with SS amplified library fragments, and (4) enriches
DNA-containing beads from null beads by another magnetic bead
capture using annealing primers. The final SS bead library is fed
to the SuperPyroSequencing instrument for sequencing and
analysis.
NanoBioPrep.sup.SPS Ligation Module
[0214] In one aspect, a device is provided that comprises massively
a parallel microchip-based instrument utilizing MOV valves, pumps,
and routers to automate the individual ligation of 4,032 different
pairs of adaptors onto 4,032 different libraries of polished
fragments per run, with subsequent pooled nick repair and
denaturation to generate key-coded, single-stranded libraries. The
NanoBioPrepSPS Ligation Module can consist of 42 microchips each
with 96 channels (FIG. 56). Each channel of the microchip will
process an individual library of fragments by ligating two adaptors
onto each fragment. A single NanoBioPrepSPS microchip is described
that implements the simultaneous addition of adaptors for 96
libraries.
Loading Libraries onto Microchips
[0215] In one embodiment libraries in microtiter plates such as 384
well can be transferred 96 samples at a time to a microchip (FIG.
57) using an array of capillary transfer tubes at 9 mm spacing,
termed a capillary cassette. Lower and higher amounts of
capillaries can be used. FIG. 58 shows a picture of a 96 channel
capillary cassette used for reactions. For this NanoBioPrepSPS
example, the capillaries can be just long enough to dip into a
microtiter plate well and just wide enough to fill by capillary
action. After filling from a microtiter plate, the transfer
capillary cassette is moved robotically to the 96 input wells of
microchip which has 96 ligation circuits in an 8.times.12 format at
9 mm spacing. The capillary cassette is then briefly cleaned before
reuse to fill the next microchip. We have previous built capillary
cassettes and cleaning stations.
Adaptor Ligation Reaction
[0216] In one embodiment, the microchip or other device can move
the sample from the array of capillaries using pressure or vacuum,
or electrical driven, centrifugation or other forces well known to
one skilled in the art. For example, a 96 on-chip MOV pumps
attached to the input wells can pump the libraries into the
microchip as shown in FIGS. 59 and 60. The samples are mixed in a
MOV mixer with 96 individual ligation mixtures, and pumped into a
nano-ligation reaction chamber (FIG. 58), where they are incubated
for example for 5 min. This produces mixtures of adaptors attached
to the input sheared library sample DNA. FIG. 58 shows two ligation
reaction circuits while FIG. 59 shows the mask design for a 96
channel NanoBioPrepSPS.
[0217] In one embodiment, each adaptor can have a key such as a six
base that serves to identify the library after sequencing (provided
that each set of 4,032 libraries is analyzed separately per
SuperPyroSequencing analysis run which can be accomplished by
simply dividing the reactors). The adaptors will contain nested PCR
and sequencing priming sites, blunt 3' ends and 5' overhangs; one
adaptor of each pair will have a biotin on the 5' end. Since a 6
base long sequence generates 4,096 individual keys, and a 42
microchip device with 96 channels requires 4,032 unique keys, the
remaining available 64 keys can be used for quality controls
incorporated into each NanoBioPrepSPS run, to monitor optimum
performance. After ligation, each ligated fragment will contain a
PCR priming site, sequencing primer site, and a six nucleotide long
key sequence on one end, polished insert genomic library DNA, and a
second end with both PCR and sequencing priming sites, as well as a
key sequence.
[0218] In one embodiment, following ligation, the 96 uniquely
encoded libraries will be pooled first from one microchip and then
for all 42 microchips, and 20 quality control key sequences added,
one group with ten control sequences of "normal" sequencing
difficulty, five control sequences with increased difficulty, and
five challenging control sequences including all four homopolymers
runs.
[0219] In one embodiment, reaction chambers such as 800 nL can be
used or other volumes such as 400 to 200 nL reactions performed.
384-channel microchips would create a Ligation Module that could
for example process 512,000 libraries per day with 42 microchips
and scale linearly with additional microchips or instruments.
[0220] In one embodiment, Pre-binding of one of the adaptors via
for example a biotin-streptavidin linkage to a paramagnetic bead
would result in bead-bound fragments with separate adaptors on each
end to manipulate the 4,032 reactions using magnetics after
ligation. The MOV micropumps routinely work with beads in
microchips and captures beads in channels with magnets (FIG.
61).
Nick Repair
[0221] In one aspect, after ligation, the beads (or libraries) from
all microchips in the device can be pooled and if on beads trapped
by a magnetic field in a 5 mL Repair Reactor. The bead vortex and
magnetic bead actuation devices used in its Sample Capture and
Preparation Module (being developed for biodefense applications)
enable a device termed BeadStorm.TM. device that dispenses, mixes,
and traps magnetic bead suspensions in a temperature controlled
chamber. The nicks at the ends of all ligated adaptors will be
repaired by Bst DNA polymerase. Following nick repair, if the DNA
has not yet been attached to beads, pre-washed and equilibrated
streptavidin beads are added and the repaired DNA attached by the
biotin bound to one set of adapters. The beads are washed to remove
unattached fragments and adapters, alkaline denatured, and another
set of 8 keyed single-stranded QC sequences added. The released
single strands are moved to the emPCR module and the magnetic
microspheres discarded. The Repair Reaction and denaturation steps
should take approximately 40 min and will be done in a single batch
per run. The upstream Ligation Module microchips are regenerated
and another run begun which can be while the Repair Reaction is
being processed.
[0222] In one embodiment quality of a library can be assessed using
an Agilent 2100 or similar device or in the NanoBioPrepSPS
instrument Automation may produce uniform libraries that lead to
the elimination of the quality check at this point. If necessary a
single-channel CE component can be added to for the Ligation
Module.
NanoBioPrep.sup.SPS emPCR Module
[0223] In one aspect, the NanoBioPrepSPS emPCR Module will bind the
DNA to optically-transparent capture beads to accommodate detection
of downstream sequencing reactions, prepare and thermal cycle
emulsion PCR (emPCR) at up to 100 mL volumes, denature the
resulting amplicons, and isolate DNA containing beads as shown in
FIG. 61.
Binding to DNA Capture Beads
[0224] In one aspect, SS DNA prepared in the Ligation Module with
ligated priming and key sequences will be annealed to polystyrene
or other beads containing a complementary DNA capture primer. The
beads will be prepared separately off the device. Templates will be
annealed by heating the solution to 80.degree. C. in a 25 mL MBI
BeadStorm processor and then ramping down the temperature with
holds every ten degrees. The temperature ramp and hold times can be
individually optimized. Another 8 keyed single stranded QC
sequenced can be added at this step.
Emulsion Phase PCR Amplification.
[0225] In one aspect, the emPCR reactions will be thermal cycled,
the emulsion broken, and the beads with amplified double-stranded
products purified. Scaleup to 42 microchips with approximately 30
mL of PCR reaction mixture in a total volume of 100 mL per run can
be done. Because the total time for the emPCR step is about 6 hrs,
which will encompass eight 45 min runs, 9 parallel emPCR reactors
will be required, each capable of processing the 100 mL emPCR
reactions for the throughput in this example.
[0226] The samples for each emPCR run of 4,032 libraries will be
flowed into a 100 mL tube that runs through the emPCR reactor;
alternatively, the emPCR may also be performed between two plates.
Once the polymerase enzyme has been heat-activated in a
pre-treatment chamber, the samples will be moved into the common
reaction chamber which will cycle up to nine simultaneous large
volume PCR reactions. The final 12 keyed QC sequenced beads are
added at this step.
[0227] In one embodiment emPCR can initially be done in
conventional 96 well microtiter plates while the eight parallel
emPCR reactors are designed. For large volume thermal cycling, in
one embodiment three circulating water baths with selection valves
can produce a thermal cycling instrument capable of processing high
volumes with excellent ramps. This instrumentation has been
previously built (FIG. 62) and shown to enable rapid
thermocycling--due to the optimal heat-transfer properties of
water--to work well for cycle sequencing and PCR. Software can
control the three circulating water baths and operate the full
scale valves that select the water and temperature to be
circulated. Emulsion chemistries can create mono-disperse emulsions
with sufficient volumes to produce 1,000 base long fragments per
micro-emulsion. In addition to using three circulating sources of
water the temperature can be changed by circulating air or liquids
with different temperatures. In a simple implementation,
essentially three hair driers set to three different temperatures
could be used to quickly change the temperature of a sample. The
heated air could be recirculated or a fixed temperature maintained
by running the heaters or hair driers at constant temperatures.
Enrichment of Single-Strand DNA Beads
[0228] In one aspect, beads with single stranded DNA can be
collected and then enriched with a magnetic pull-up, for example by
the method of Margulies et al, by (1) replacing the MPC-S with our
custom device, (2) replacing centrifugation steps by settling or
filtration to change buffers and wash the beads, and (3) adjusting
the procedure for the density of the optical beads rather than
Sepharose beads. To collect the emPCR beads from the emulsion, the
PCR amplified emPCR solution can have isopropyl alcohol added, the
solution mixed and forced through a sieving filter using a syringe
pump. The filter is washed and moved to a BeadStorm where annealing
buffer with 0.1% Tween is added and the amplified DNA alkaline
denatured. After incubation, the single stranded DNA containing
beads can be concentrated by settling, the supernatant is removed,
and annealing buffer added. After washing, magnetic capture beads
are added to purify the beads with single stranded DNA by
pull-down, the supernatant and unbound beads removed, and Melting
Solution added to break the hybridization. The magnetic beads are
trapped while the supernatant containing the enriched beads with
single-strand template DNA is removed. The NanoBioPrepSPS can then
output the pooled and keyed purified libraries ready for
SuperPyroSequencing.
42 Microchip Ligation Device and an emPCR Module and
Integration
[0229] In one aspect, the Ligation Module can be expanded from 1 to
42 microchips and latching valves as described below used to design
a 42 microchip device. The workflow with a single microchip
Ligation Module and a single channel emPCR Module can be used to
process human-derived cancer cell line libraries in a
non-integrated workflow. A single Ligation Module microchip and
downstream processes can be integrated with a single-channel,
flowthrough 100 mL emPCR thermal cycler to make an automated
integrated prototype capable of processing 96 libraries per
run.
[0230] In one embodiment To complete the NanoBioPrepSPS, the 42
microchip Ligation Module can be integrated with a nine-channel
emPCR Module as disclosed in this instant invention. The microchip
Ligation Module can be integrated physically and through software
with the one channel emPCR Module in a breadboard. The full 42
microchip Ligation Module can be built and integrated with a
9-channel emPCR Module. A fully integrated NanoBioPrepSPS can be
optimized and samples analyzed on the SuperPyroSequencing device to
perform DNA sequencing for example by pyrosequencing, sequencing by
synthesis, sequencing by ligation or other methods well known to
one skilled in the art to achieve a system capable of complete
human de novo sequencing in one day.
[0231] In one embodiment, the ligation module can be expanded from
1 to 42 microchips. The latching valves can be used to control the
42 microchips and will begin to design the full system hardware. In
one embodiment latching microfluidic valve structures controlled
independently using an on-chip pneumatic demultiplexer are used
(FIG. 63). These structures are based on the pneumatic MOV valves
and depend upon their normally-closed nature. Vacuum or pressure
pulses as short as 120 ms are adequate to hold these latching
valves open or closed for several minutes. In addition, an on-chip
demultiplexer was demonstrated that requires only n pneumatic
inputs to control 2(n-1) independent latching valves. Latching
valves consisting of both three- and four-valve circuits have been
demonstrated (W. H. Grover, R. H. C. Ivester, E. C. Jensen and R.
A. Mathies. 2006. Development and multiplexed control of latching
pneumatic valves using microfluidic logical structures.
Lab-on-a-chip. Electronic publication). This technology in effect
moves banks of solenoids onto the microchip and reduces cost and
complexity.
[0232] In one embodiment, a pneumatic controlled NanoBioPrep
microchip can be built using latching valves for example for 42
microchips. The capillary cassette transfer mechanism interfaces a
robotics system with the capillary cassette to load a four
microchip device with 2,500 valves.
[0233] In one embodiment, the emPCR Module can handle 100 mL in a
single channel for example. A high capacity circulating thermal
cycler (as shown in FIG. 64) can be built with three different
independently thermal cycling regions. Nine separate 100 mL emPCR
reactors will be required to share the main circulating thermal
cycler, which will continuously perform the same cycling protocol.
A pretreatment chamber can accommodate binding to polystyrene or
other beads and prepare the emulsion, before adjusting the
temperature to accommodate quick start requirements. A
post-treatment chamber enables post treatment requirements such as
breaking the emulsions and extractions. All three thermo-cycling
chambers can share the bulk circulating water; 4.degree. C. water
and additional temperatures as needed will be added; this is simply
another circulating water bath and three full scale COTS valves and
solenoids. Engineering calculations, studies, and experiments can
determine effects of surface-to-volume ratios and the depth (mm) of
reaction tolerated by the demands of cycling uniformity to define
optimal geometry for the reactors, i.e., long thick tubes, oval
tubing, or parallel plates, and validated with scientific
experiments defining performance. Separation of those beads
carrying amplicons from null beads can occur in the BeadStorm
module, as a final step before SuperPyroSequencing or other
analysis methods. Hardware to implement devices can be integrated
under software control.
[0234] For example, a single microchip Ligation Module and the
single channel emPCR Module can be used to process human cell line
libraries in a non-integrated workflow. Control processing can be
performed manually with GS20 reagents and procedures.
[0235] In another embodiment the NanoBioPrepSPS can be scaled-up
and the Ligation Module and emPCR Module fully integrated. A full
42 microchip Ligation Module can be built by means well known to
one skilled in the art. For example (1) a tower can be fabricated
to hold the microchips, (2) build the Microchip Controller which
will operate the latching MOV valves, pumps, and routers, (3) the
NanoBioPrep robotic platform and the first 42 microchips can be
microfabricated and tested, and (4) the 42 microchip Ligation
Module can be integrated and tested. In parallel, the BeadStorm
design can be evolved to process the pooled samples. The emPCR
Module can be expanded to hold 9 runs from a Ligation Module. The
emPCR performance can be optimized using both the 454 GS20 and
SuperPyroSequencing. The 42 microchip Ligation Module can be
plumbed to the fully expanded emPCR module and the process
optimized, based on the one microchip-one channel device already
developed. With the NanoBioPrepSPS as described, a 10% of a
complete human genome can be done or a complete human de novo
sequencing.
[0236] While preferred embodiments of the present invention have
been shown and described herein, it will be obvious to those
skilled in the art that such embodiments are provided by way of
example only. Numerous variations, changes, and substitutions will
now occur to those skilled in the art without departing from the
invention. It should be understood that various alternatives to the
embodiments of the invention described herein may be employed in
practicing the invention. It is intended that the following claims
define the scope of the invention and that methods and structures
within the scope of these claims and their equivalents be covered
thereby.
* * * * *