U.S. patent application number 10/438257 was filed with the patent office on 2003-10-23 for valve for use in microfluidic structures.
This patent application is currently assigned to Micronics, Inc.. Invention is credited to Williams, Clinton L..
Application Number | 20030197139 10/438257 |
Document ID | / |
Family ID | 22796813 |
Filed Date | 2003-10-23 |
United States Patent
Application |
20030197139 |
Kind Code |
A1 |
Williams, Clinton L. |
October 23, 2003 |
Valve for use in microfluidic structures
Abstract
A valve for use in microfluidic structures. The valve uses a
spherical member, such as a ball bearing, to depress an elastomeric
member to selectively open and close a microfluidic channel. The
valve may be operated manually or by use of an internal force
generated to shift the spherical member to its activated
position.
Inventors: |
Williams, Clinton L.;
(Seattle, WA) |
Correspondence
Address: |
SEED INTELLECTUAL PROPERTY LAW GROUP PLLC
701 FIFTH AVE
SUITE 6300
SEATTLE
WA
98104-7092
US
|
Assignee: |
Micronics, Inc.
Redmond
WA
|
Family ID: |
22796813 |
Appl. No.: |
10/438257 |
Filed: |
May 13, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10438257 |
May 13, 2003 |
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09887820 |
Jun 22, 2001 |
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6581899 |
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60213865 |
Jun 23, 2000 |
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Current U.S.
Class: |
251/7 ; 251/213;
251/61 |
Current CPC
Class: |
B01F 25/433 20220101;
B01L 3/5023 20130101; B01L 2400/0406 20130101; G01N 2035/00544
20130101; B01L 3/5027 20130101; F16K 99/0013 20130101; B01L
2300/0867 20130101; F16K 2099/008 20130101; Y10T 137/7722 20150401;
B01F 33/30 20220101; B01F 33/451 20220101; G01N 27/06 20130101;
G01N 2035/00237 20130101; B01F 25/4331 20220101; B01L 2400/0457
20130101; F16K 2099/0084 20130101; B01L 2200/0636 20130101; B01F
31/441 20220101; B01L 2300/0822 20130101; F16K 99/0023 20130101;
B01L 2300/0887 20130101; F16K 99/0046 20130101; B01L 3/502738
20130101; F16K 99/0001 20130101; B01L 2400/0415 20130101; F15C 3/04
20130101; F16K 99/0059 20130101; F16K 99/0015 20130101; B01L 3/5025
20130101; B01L 2400/0409 20130101; G01N 35/0098 20130101; B01L
2400/0403 20130101; F16K 99/0017 20130101; B01L 2200/10 20130101;
B01L 2400/0655 20130101; F16K 99/0011 20130101; B01L 2400/043
20130101; B01L 2400/0688 20130101; B01L 2300/0636 20130101; F15C
3/06 20130101; F16K 99/0042 20130101; B01F 33/3039 20220101; B01L
3/502715 20130101 |
Class at
Publication: |
251/7 ; 251/61;
251/213 |
International
Class: |
F16K 007/00 |
Claims
What is claimed is:
1. A valve for use in a microfluidic structure, comprising: a first
rigid layer; a first flexible layer; a first channel, formed
between said first rigid layer and said first flexible layer, said
channel having an inlet and an outlet and capable of fluid flow
from said inlet to said outlet; a spherical actuator located
adjacent said flexible layer on the side opposite said rigid layer;
and means for shifting said actuator to an actuating position such
that a portion of said flexible layer is shifted toward said rigid
layer, restricting fluid flow within said first channel.
2. The valve of claim 1, wherein said first flexible layer is
constructed from an elastomeric material.
3. The valve of claim 1, wherein said first flexible layer is
constructed from polyvinylidene chloride.
4. The valve of claim 1, wherein said spherical actuator comprises
a metal ball bearing.
5. The valve of claim 1, wherein said shifting means comprises a
finger of a human operator.
6. The valve of claim 1, wherein said shifting means comprises
mechanical operating means.
7. The valve of claim 1, further comprising: a second rigid layer,
located adjacent said first flexible layer on the side opposite
said first channel; a second flexible layer; a second channel,
formed between said second rigid layer and said second flexible
layer, for containing said spherical actuator; a third rigid layer;
a first aperture, located in said second rigid layer, for
positioning said spherical actuator within said second channel
during actuation; a third channel, formed between said second
flexible layer and said third rigid layer, for containing said
shifting means.
8. The valve of claim 7, wherein said shifting means comprises a
fluid flowing within said third channel.
9. The valve of claim 7, wherein said second flexible layer
comprises an elastomeric material.
10. The valve of claim 7, wherein all of said rigid layers are
constructed from MYLAR.
11. A microfluidic control system, comprising: a plurality of
valves, with each valve comprising a first rigid layer; a first
flexible layer; a first channel, formed between said first rigid
layer and said first flexible layer, said channel having an inlet
and an outlet and capable of fluid flow from said inlet to said
outlet; a spherical actuator located adjacent said flexible layer
on the side opposite said rigid layer; and means for shifting said
actuator to an actuating position such that a portion of said
flexible layer is shifted toward said rigid layer, restricting
fluid flow within said first channel; and means for controlling the
operation of said plurality of valves.
12. The system of claim 11, wherein said controlling means
comprises a computer.
13. The system of claim 11, wherein said controlling means
comprises a programmable controller.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims benefit from U.S. Provisional
Patent Application Serial No. 60/213,865, filed Jun. 23, 2000,
which application is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to microscale devices for
performing analytical testing and, in particular, to a valve for
use in laminated plastic microfluidic structures.
[0004] 2. Description of the Prior Art
[0005] Microfluidic devices have recently become popular for
performing analytical testing. Using tools developed by the
semiconductor industry to miniaturize electronics, it has become
possible to fabricate intricate fluid systems which can be
inexpensively mass produced. Systems have been developed to perform
a variety of analytical techniques for the acquisition of
information for the medical field.
[0006] Microfluidic devices may be constructed in a multi-layer
laminated structure where each layer has channels and structures
fabricated from a laminate material to form microscale voids or
channels where fluids flow. A microscale channel is generally
defined as a fluid passage which has at least one internal
cross-sectional dimension that is less than 100 .mu.m and typically
between about 0.1 .mu.m and about 500 .mu.m. The control and
pumping of fluids through these channels is affected by either
external pressurized fluid forced into the laminate, or by
structures located within the laminate.
[0007] Many different types of valves for use in controlling fluids
in microscale devices have been developed. U.S. Pat. No. 4,895,500,
which issued on Jan. 23, 1990, describes a silicon micromechanical
non-reverse valve which consists of a cantilever beam extending
over a cavity and integrally formed with the silicon wafer such
that the beam can be shifted to control flow within channels of the
microfluidic structure.
[0008] U.S. Pat. No. 5,443,890, which issued Aug. 22, 1995 to
Pharmacia Biosensor AB, describes a sealing device in a
microfluidic channel assembly having first and second flat surface
members which when pressed against each other define at least part
of a microfluidic channel system between them.
[0009] U.S. Pat. No. 5,593,130, which issued on Jan. 14, 1997 to
Pharmacia Biosensor AB, describes a valve for use in microfluidic
structures in which the material fatigue of the flexible valve
membrane and the valve seat is minimized by a two-step seat
construction and the fact that both the membrane and the seat are
constructed from elastic material.
[0010] U.S. Pat. No. 5,932,799, which issued Aug. 3, 1999 to YSI
Incorporated, teaches a microfluidic analyzer module having a
plurality of channel forming laminate layers which are directly
bonded together without adhesives, with a valve containing layer
directly adhesivelessly bonded over the channel containing layers
and a flexible valve member integral with the valve layer to open
and close communication between feed and sensor channels of the
network.
[0011] U.S. Pat. No. 5,962,081, which issued Oct. 5, 1999 to
Pharmacia Biotech AB, describes a method for the manufacturer of
polymer membrane-containing microstructures such as valves by
combining polymer spin deposition methods with semiconductor
manufacturing techniques.
[0012] U.S. Pat. No. 5,977,355, which issued on Oct. 26, 1999 to
Xerox Corporation, describes a valve array system for microdevices
based on microelectro mechanical systems (MEMS) technology
consisting of a dielectric material forming a laminate which is
embedded within multiple laminate layers.
[0013] U.S. Pat. No. 6,068,751, which issued on May 30, 2000,
describes a microfluidic delivery system using elongated
capillaries that are enclosed along one surface by a layer of
malleable material which is shifted by a valve having a
electrically-powered actuator.
[0014] U.S. patent application Ser. No. 09/677,250, filed Oct. 2,
2000, and assigned to the assignee of the present invention
describes a one way check valve for use in laminated plastic
microfluidic structures. This valve allows one way flow through
microfluidic channels for use in mixing, dilution, particulate
suspension and other techniques necessary for flow control in
analytical devices.
[0015] Several types of valves are commonly used for fluid
management in flow systems. Flap valves, ball-in-socket valves, and
tapered wedge valves are a few of the valve types existing in the
macroscale domain of fluid control. However, in the microscale
field, where flow channels are often the size of a human hair
(approximately 100 microns in diameter), there are special needs
and uses for valves which are unique to microscale systems,
especially microfluidic devices incorporating fluids with various
concentrations of particulate in suspension. Special challenges
involve mixing, dilution, fluidic circuit isolation, and
anti-sediment techniques when employing microscale channels within
a device. The incorporation of a simple compact valve within
microscale devices addresses these potential problems while
maintaining high density of fluidic structure within the
device.
SUMMARY OF THE INVENTION
[0016] It is therefore an object of the present invention to
provide an efficient and reliable valve suitable for use in a
microfluidic system.
[0017] It is a further object of the present invention is to
provide a microfluidic valve which can be integrated into a
cartridge constructed of multi-layer laminates.
[0018] It is a further object of the present invention is to
provide an array of microfluidic valves that can be integrated into
a cartridge constructed of multi-layer laminates.
[0019] These and other objects of the present invention will be
more readily apparent in the description and drawings that
follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a fragmentary cross-sectional view of a
microfluidic device containing a basic ball bearing valve according
to the present invention;
[0021] FIG. 2 is a fragmentary cross-sectional view of the valve of
FIG. 1 shown in its activated position;
[0022] FIG. 3 is a fragmentary cross-sectional view of another
embodiment of a ball bearing valve according to the present
invention; and
[0023] FIG. 4 is a perspective view of a microfluidic array which
uses a plurality of ball bearing valves according to the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Referring now to FIG. 1, there is shown a microfluidic valve
assembly, generally indicated at 10, which contains a valve
constructed according to the present invention. Assembly 10
includes a spherical member or ball bearing 12 which is located
within a channel 14 formed between a rigid top layer 16 and a rigid
interior layer 18 within assembly 10. Layer 16 and layer 18 each
contain a cutout area 20 and 22 respectively within which ball
bearing 12 is contained in channel 14. Rigid layers 16, 18 may be
constructed from a material such as MYLAR. Spherical member 12 may
be constructed from metal, hard plastic, or any other similar
material.
[0025] A membrane 24 constructed of a flexible material is located
adjacent layer 18 opposite channel 14. Membrane 24, which is
preferably made from a thin elastomeric material, completely
isolates channel 14 from a channel 26 by spanning across cutout
area 22. One suitable material that may be used for membrane 24 is
polyvinylidene chloride (PVDC) which is the material commonly used
as SARAN WRAP.RTM. film. Channel 26 is capable of carrying fluids
within 10 assembly 10, and in the present embodiment is formed by a
narrow section 26a and a wider section 26b. Channel section 26b is
formed by layer 18 along with adjacent membrane 24, and a rigid
bottom layer 28, while section 26a is located within membrane 24
and an additional rigid layer 30 adjacent bottom layer 28.
[0026] In operation, the flow of a fluid traveling within channel
26 can be controlled within assembly 10 by spherical member 10.
Referring now to FIG. 2, member 12 is shifted by a sufficient force
in the direction shown by arrow A. This force may be applied
manually using the finger of a human operator, or by any suitable
mechanical means as known in the art. This movement causes flexible
membrane 24 to contact bottom layer 28, closing channel 26 to any
fluid movement between channel section 26a and section 26b. Note
that layer 18 acts to aid in centering member 12 in the process of
activating valve assembly 10, as member 12 is essentially captured
within cutout area 22 of layer 18. When the operating force is
removed from member 12, said member is shifted back to its
unactuated position as shown in FIG. 1 by virtue of the elastomeric
property of membrane 24.
[0027] FIG. 3 illustrates a second embodiment of a valve assembly
constructed according to the present invention. It will be
understood that similar parts will be given the same index
numerals. Referring now to FIG. 3, there is shown a valve assembly
10a having a spherical member 12 located within a channel 14 which
is formed between a layer 18 and an elastomeric layer 16a.
[0028] Elastomeric membrane 24 is located adjacent layer 18
opposite channel 14, while spherical member 12 is situated in
cutout section 22 within layer 18 and contacts member 24 at this
location, as was previously shown in FIG. 1. Channel 26, which
consists of a narrow section 26a and a wider section 26b, is formed
between membrane 24 and bottom layer 28, and is capable of carrying
fluids within a microfluidic circuit.
[0029] An upper channel 36 is formed within assembly 10a between
layer 16a and a rigid upper layer 38. Channel 36 contains a fluid
which is capable of providing a force capable of activating valve
assembly 10a. As can be clearly seen in FIG. 3, fluid flowing in
the direction of arrow B will flow over spherical member 12, which
is located beneath layer 16a.
[0030] To operate valve assembly 10a, if the force generated by a
fluid flowing in direction B within channel 36, the fluid will
force membrane 24 downwardly in the direction of arrow A, causing
member 12 to shift and causing membrane 24 to contact layer 28,
closing channel 26 to any fluid movement between channel 26a and
26b. When the flow of the fluid within channel 36 is reduced such
that the force acting upon member 12 is less than that force
exerted by membrane 24 on the lower part of member 12, member 12
will return to the position shown in FIG. 3, and thus allowing
fluid flow within channel 26.
[0031] The valve assembly of the present invention can also be used
to control a microfluidic array. Referring now to FIG. 4, there is
shown a microfluidic array, generally indicated at 50. Array 50
consists of a lower array section 52 and an upper array section 54.
Section 52 contains a plurality of spaced apart indentations 56
which are sized to contain a plurality of spherical members 12 as
taught in FIGS. 1-3. Also within section 52, there is contained a
microfluidic circuit (not shown) which is constructed having
channels similar to that shown in FIG. 3. This circuit may be
designed to perform many functions which are familiar to those
skilled in the art of microfluidic circuitry design.
[0032] Section 54 may be constructed similar to the valve circuitry
shown in FIG. 3 in that the lower surface is constructed for a
elastomeric material which is deformed by spherical members 12 when
the valves are in the inactive position. The control of the
operation of the valves may be done using fluidic channels, similar
to channel 36 in FIG. 3, or operation of the valves may also be
accomplished using common electrical, magnetic, or pneumatic means,
as is well known in the art.
[0033] The control of the operation of array 50 is accomplished by
use of external control means 60 which is coupled to section 54 via
a cable 62. Control means 60 may be a computer or programmable
control or the like, or any device familiar to those skilled in the
art. Or, alternatively, array 50 could be inserted as a cartridge
into a separate machine which would control operation of the valves
within the array.
[0034] While the present invention has been shown and described in
terms of several preferred embodiments thereof, it will be
understood that this invention is not limited to these particular
embodiments and that many changes and modifications may be made
without departing from the true spirit and scope of the invention
as defined in the appended claims.
* * * * *