U.S. patent application number 17/049142 was filed with the patent office on 2021-08-12 for analyte capturing devices with fluidic ejection devices.
This patent application is currently assigned to HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.. The applicant listed for this patent is HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.. Invention is credited to Daniel Curthoys, Hilary Ely, Alexander Govyadinov, Pavel Kornilovich.
Application Number | 20210245153 17/049142 |
Document ID | / |
Family ID | 1000005552238 |
Filed Date | 2021-08-12 |
United States Patent
Application |
20210245153 |
Kind Code |
A1 |
Kornilovich; Pavel ; et
al. |
August 12, 2021 |
ANALYTE CAPTURING DEVICES WITH FLUIDIC EJECTION DEVICES
Abstract
In one example in accordance with the present disclosure, an
analyte capturing device is described. The analyte capturing device
includes a first substrate having microfluidic channels disposed
therein and a second substrate disposed on top of the first
substrate. A chamber is disposed through the second substrate and
captures beads therein, which beads adsorb analytes. The analyte
capturing device includes at least one fluid ejection device
disposed in the first substrate to draw an analyte-containing
solution through the beads disposed within the chamber.
Inventors: |
Kornilovich; Pavel;
(Corvallis, OR) ; Curthoys; Daniel; (Corvallis,
OR) ; Ely; Hilary; (Corvallis, OR) ;
Govyadinov; Alexander; (Corvallis, OR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P. |
Spring |
TX |
US |
|
|
Assignee: |
HEWLETT-PACKARD DEVELOPMENT
COMPANY, L.P.
Spring
TX
|
Family ID: |
1000005552238 |
Appl. No.: |
17/049142 |
Filed: |
July 9, 2018 |
PCT Filed: |
July 9, 2018 |
PCT NO: |
PCT/US2018/041216 |
371 Date: |
October 20, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01L 2300/0663 20130101;
B01L 3/502746 20130101; B01L 2400/043 20130101; B01L 3/502715
20130101; B01L 2400/0421 20130101; G01N 33/48707 20130101; B01L
3/50273 20130101 |
International
Class: |
B01L 3/00 20060101
B01L003/00; G01N 33/487 20060101 G01N033/487 |
Claims
1. An analyte capturing device, comprising; a first substrate
having microfluidic channels disposed therein; a second substrate
disposed on top of the first substrate; a chamber disposed through
the second substrate to capture beads that adsorb analytes; and at
least one fluid ejection device disposed in the first substrate to
draw an analyte-containing solution through the beads disposed
within the chamber.
2. The device of claim 1, wherein the chamber is a slot fluidly
coupled to multiple fluid ejection devices.
3. The device of claim 2, wherein the chamber comprises multiple
holes disposed between the slot and the multiple fluid ejection
devices.
4. The device of claim 1, further comprising a perforated membrane
disposed between the first substrate and the second substrate to
prevent beads from entering the microfluidic channels of the first
substrate.
5. The device of claim 1, wherein: the second substrate has a
thickness of between 100 and 775 microns; and the chamber has a
volume of between 0.01 microliter to 10 microliters.
6. The device of claim 1, further comprising an analyte channel in
the first substrate to direct the analyte, following capture, away
from the chamber.
7. The device of claim 1, further comprising a third substrate
disposed on the second substrate to capture additional beads.
8. A method comprising: capturing beads which adsorb analytes in a
mesofluidic chamber of an analyte capturing device; activating a
microfluidic fluid ejection device to generate a flow through the
mesofluidic chamber; and expelling a carrier fluid from the analyte
capturing device.
9. The method of claim 8, further comprising drawing an elution
buffer through the beads to remove the analyte from the beads.
10. The method of claim 9, further comprising activating the
microfluidic fluid ejection device to expel the analyte and elution
buffer from the analyte capturing device.
11. The method of claim 9, further comprising activating a chamber
pump to draw the analyte and elution buffer away from the
chamber.
12. An analyte capturing device, comprising: a planar microfluidic
substrate having microfluidic channels disposed therein; a planar
silicon substrate disposed on top of the planar microfluidic
substrate; at least one mesoscale chamber disposed through the
planar silicon substrate to capture beads therein, which beads
adsorb analytes; and a microscale fluid ejection device disposed in
the planar microfluidic substrate to draw an analyte-containing
solution through the beads disposed within the chamber, wherein the
fluid ejection device comprises: an ejection chamber to hold a
volume of fluid; an opening; and an ejector to eject a portion of
the volume of fluid through the opening.
13. The device of claim 12, further comprising the beads which
adsorb analytes disposed within the chambers, wherein: the beads
have a surface treatment selected based on the analyte; and a
diameter of the beads is between 5 and 20 microns.
14. The device of claim 12, wherein the at least one mesoscale
chamber comprises multiple mesoscale chambers.
15. The device of claim 14, wherein the multiple mesoscale chambers
have at least one of different diameters and different
cross-sectional areas.
Description
BACKGROUND
[0001] Analyte concentration is a sample preparation operation used
in many chemical analysis operations. For example, concentration of
deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) is a sample
preparation step in nucleic acid testing. Concentrating the
analytes enhances the efficacy and accuracy of subsequent analysis
operations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] The accompanying drawings illustrate various examples of the
principles described herein and are part of the specification. The
illustrated examples are given merely for illustration, and do not
limit the scope of the claims.
[0003] FIGS. 1A-1C are diagrams of an analyte capturing device with
fluid ejection devices, according to an example of the principles
described herein.
[0004] FIG. 2 is a flow chart of a method for analyte capturing
with fluid ejection devices, according to an example of the
principles described herein.
[0005] FIGS. 3A-3C are diagrams of an analyte capturing device with
fluid ejection devices, according to another example of the
principles described herein.
[0006] FIG. 4 is a cross-sectional diagram of an analyte capturing
device with fluid ejection devices, according to another example of
the principles described herein.
[0007] FIG. 5 is a diagram of a method for analyte capturing with
the fluid ejection devices, according to another example of the
principles described herein.
[0008] FIG. 6 is a cross-sectional diagram of an analyte capturing
device with fluid ejection devices, according to another example of
the principles described herein.
[0009] FIG. 7 is a top view of an analyte capturing device with
fluid ejection devices, according to another example of the
principles described herein.
[0010] Throughout the drawings, identical reference numbers
designate similar, but not necessarily identical, elements. The
figures are not necessarily to scale, and the size of some parts
may be exaggerated to more clearly illustrate the example shown.
Moreover, the drawings provide examples and/or implementations
consistent with the description; however, the description is not
limited to the examples and/or implementations provided in the
drawings.
DETAILED DESCRIPTION
[0011] Analyte concentration is a sample preparation operation in
many chemical analysis operations. For example, concentration of
deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) is a sample
preparation step in nucleic acid testing. Concentrating the
analytes enhances the efficacy and accuracy of subsequent analysis
operations.
[0012] There are various ways to concentrate an analyte. As a
specific example, certain materials may have an affinity for an
analyte and may therefore attract the analyte. Quantities of this
material can be formed into microscopic beads and may be included
in a solution to adsorb the analyte to the bead surface.
[0013] While using beads in solution is effective at separating the
analyte, such systems present certain complications. For example,
once drawn to the beads, the beads themselves should be separated
from the rest of the solution such that the analyte may be removed.
One way to separate the beads is magnetic gathering. In this
method, the beads have a paramagnetic core and are pulled from the
solution by an external permanent magnet. In another example, the
beads are separated from the rest of the solution based on size
differences. For example, a size of objects in a biological sample
may be between 0.1-1.0 microns whereas the beads may be between
1-10 microns in diameter. Thus, if a mixture with the beads and
analyte is passed through a filter with pore sizes of several
microns, the beads will be trapped while the rest of the solution
will pass through. Since at this stage, the analyte, such as DNA
molecules, are still attached to the bead surface, trapping beads
in a filter concentrates DNA.
[0014] While such operations are effective at concentrating an
analyte within a solution, improved operations in this field would
increase efficacy and subsequent operation accuracy. Accordingly,
the present specification describes a system and method for
concentrating analyte using analyte-adsorbing beads, and for
separating the analyte-adsorbing beads from the rest of the sample
fluid. Specifically, the present specification relies on fluid
ejection devices and a mesoscopic fluid delivery chamber to capture
the analyte-adsorbing beads.
[0015] The fluid ejection devices expel waste carrier fluid while
the analyte is retained within a chamber. To eject the fluid, the
fluid ejection devices include a number of components.
Specifically, the fluid to be ejected is held in an ejection
chamber. A fluid actuator operates to dispel the fluid in the
ejection chamber through an opening. As the fluid is expelled, a
negative capillary pressure within the ejection chamber draws
additional fluid into the ejection chamber, and the process
repeats. In this example, the ejection chamber has microscale
dimensions. Fluid is fed to the ejection chamber via a fluid feed
channel, which is larger, for example having mesoscale
dimensions.
[0016] The chamber of the analyte capturing device has dimensions
to accommodate beads having a diameter sufficiently large that they
are trapped in the chamber and cannot enter the microfluidic
passageways nor the ejection chamber. During operation, as the
ejector actuates, the solution is pulled through the chamber where
the beads are stored. As such, the analyte adheres to the surface
of the beads and the rest of the solution, i.e., a carrier fluid,
passes through to the ejection chamber to be expelled. Accordingly,
as an entire sample is treated, the carrier fluid is expelled
through the fluid ejection device and the analyte is left behind in
the chamber. From here, the analyte can be subsequently ejected
through the fluid ejection device onto a surface or into a
container. In another example, the analyte is routed to another
chamber where it can be further analyzed.
[0017] Specifically, the present specification describes an analyte
capturing device. The analyte capturing device includes a first
substrate having microfluidic channels disposed therein and a
second substrate disposed on top of the first substrate. In this
example, a chamber is disposed through the second substrate to
capture beads therein. The beads may adsorb analytes. The device
also includes at least one fluid ejection device disposed in the
first substrate to draw an analyte-containing solution through the
beads disposed within the chamber.
[0018] The present specification also describes a method. According
to the method, beads that adsorb analytes are captured in a
mesofluidic chamber of an analyte capturing device. A microfluidic
fluid ejection device is activated to generate a flow through the
mesofluidic chamber and a carrier fluid is expelled from the
analyte capturing device.
[0019] In another example, the analyte capturing device includes a
planar microfluidic substrate having microfluidic channels disposed
therein and a planar silicon substrate disposed on top of the
planar microfluidic substrate. The analyte capturing device also
includes at least one mesoscale chamber disposed through the planar
silicon substrate to capture beads therein, which beads are to
adsorb analytes. The analyte capturing device also includes
microscale fluid ejection devices disposed in the planar
microfluidic substrate to draw an analyte-containing solution
through the beads disposed within the chamber. In this example,
each fluidic ejection device includes 1) an ejection chamber to
hold a volume of fluid, 2) an opening, and 3) an ejector to eject a
portion of the volume of fluid through the opening.
[0020] In summary, using such an analyte capturing device 1)
enables analyte concentration via analyte-adsorbing beads; 2)
enables separation of the beads with adhered analyte thereon from a
carrier fluid; 3) includes a mesoscale volume to hold the
analyte-adsorbing beads, the larger volume allowing for a greater
quantity of analyte-adsorbing beads; and 4) facilitates the user of
larger analyte-adsorbing beads, reducing the fluidic resistance of
the system and thus enhancing the analyte concentration operation.
However, the devices disclosed herein may address other matters and
deficiencies in a number of technical areas.
[0021] As used in the present specification and in the appended
claims, the term "fluid ejection device" refers to an individual
component of the analyte capturing device that ejects fluid. The
fluid ejection device may be referred to as a nozzle and includes
at least an ejection chamber to hold an amount of fluid and an
opening through which the fluid is ejected. The fluid ejection
device also includes an ejector disposed within the ejection
chamber.
[0022] Further, as used in the present specification and in the
appended claims, the term "meso-" refers to a size scale of
100-1000 microns. For example, a mesofluidic layer may be between
100 and 1000 microns thick.
[0023] Further, as used in the present specification and in the
appended claims, the term "micro-" refers to a size scale of
between 10 and 100 microns. For example, a microfluidic layer may
be between 10 and 100 microns thick and a microfluidic channel may
have a cross-sectional diameter of between 10 and 100 microns.
[0024] Turning now to the figures, FIGS. 1A-1C are diagrams of an
analyte capturing device (100) with fluid ejection devices (106),
according to an example of the principles described herein.
Specifically, FIG. 1A is a top view of the analyte capturing device
(100), FIG. 1B is a cross-sectional view of the analyte capturing
device (100) without analyte-adsorbing beads disposed therein, and
FIG. 1C is a cross-sectional view of a portion of the analyte
capturing device (100) with analyte-adsorbing beads disposed
therein. While FIGS. 1A-1C depict multiple columns to eject waste
fluid, in some examples, the fluid may be passed downstream for
further processing as depicted in FIG. 4 through some or all of the
columns.
[0025] As described above, the analyte capturing device (100)
relies on fluid ejection devices (106) for capturing analytes
therein. For simplicity in FIG. 1A, just one of the fluid ejection
devices (106) is indicated with a reference number. The analyte
capturing device (100) also includes a chamber (104). It is in this
chamber (104) that analyte-adsorbing beads are captured. That is, a
solution including 1) an analyte such as DNA and 2)
analyte-adhering beads that attract the analyte are received in the
chamber (104). In some examples, the size scale of the chamber
(104) and the fluid ejection devices (106) are different. For
example, the chamber (104) may be on a mesoscale, meaning it may be
formed through a substrate (102) with a thickness between 100 and
775 microns. The fluid ejection devices (106) by comparison are on
a microscale, meaning they may be formed in a separate substrate
with a thickness of between 10 and 100 microns. In FIG. 1A, the
fluid ejection devices (106) are indicated in a dashed line
indicating their placement below the substrate (102) in which the
mesofluidic bead-capturing chamber (104) is formed.
[0026] FIG. 1B is a cross-sectional diagram of the analyte
capturing device (100), and more specifically, a cross-sectional
diagram taken along the line A-A in FIG. 1A. FIG. 1B clearly shows
the first substrate (108) in which the fluid ejection device(s)
(106-1, 106-2) are formed. In some examples, the first substrate
(108) may be formed of a polymeric material such as SU-8. As
described above, the fluid ejection devices (106), and the first
substrate (108) in which it is formed, may be microscopic. That is,
the first substrate (108) may have a thickness of between 10 and
100 microns. In some examples, the first substrate (108) may be
planar and may be referred to as a microfluidic substrate due to
its containing microfluidic structures.
[0027] To facilitate the ejection of fluid, each fluid ejection
device (106) includes various components. For example, fluid
ejection devices (106-1, 106-2) include an ejection chamber (112-1,
112-2) to hold an amount of fluid to be ejected, openings (114-1,
114-2) through which the amount of fluid is ejected, and ejectors
(110-1, 110-2), disposed within the ejection chambers (112), to
eject the amount of fluid through the openings (114-1, 114-2).
[0028] Turning to the ejectors (110), the ejector (110) may include
a firing resistor or other thermal device, a piezoelectric element,
or other mechanism for ejecting fluid from the ejection chamber
(112). For example, the ejector (110) may be a firing resistor. The
firing resistor heats up in response to an applied current. As the
firing resistor heats up, a portion of the fluid in the ejection
chamber (110) vaporizes to generate a bubble. This bubble pushes
fluid through the opening (114). As the vaporized fluid bubble
collapses, fluid is drawn into the ejection chamber (112) from a
passage that connects the fluid ejection device (106) to the
bead-capturing chamber (104), and the process repeats. In this
example, the fluid ejection device (106) may be a thermal inkjet
(TIJ) fluid ejection device (106).
[0029] In another example, the ejector (110) may be a piezoelectric
device. As a voltage is applied, the piezoelectric device changes
shape which generates a pressure pulse in the ejection chamber
(112) that pushes the fluid out the opening (114). In this example,
the fluid ejection device (106) may be a piezoelectric inkjet (PIJ)
fluid ejection device (106).
[0030] Disposed on top of the first substrate (108) is a second
substrate (102). The second substrate (102) may be formed of a
different material, such as silicon. The second substrate (102)
defines in part the chamber (104) through which the solution is
passed and in which the beads are captured. In some examples, the
second substrate (102) may be planar and may be referred to as a
silicon substrate due to its being formed of a silicon
material.
[0031] The chamber (104) may take many forms. For example, as
depicted in at least FIG. 1B, the chamber (104) may be a slot and
may be funnel-shaped. The slot may be fluidly coupled to multiple
fluid ejection devices. In another example, as depicted in FIGS.
3A-3C, the bead-capturing chamber (104) may include multiple fluid
delivery holes beneath the slot, which holes are coupled to
multiple fluid ejection devices (106).
[0032] The second substrate (102) and the associated chamber (104)
may be on the mesoscale. That is, a thickness of the second
substrate (102) may be between 100 and 775 microns thick, and the
chamber (104) may have a volume of between 0.01 microliter and 10
microliters, Being on the mesoscale, the chamber (104) can capture
larger analyte-adhering beads and can retain a higher quantity of
the analyte-adhering beads, both of which increase the efficiency
of analyte concentration as described below.
[0033] Moreover, the analyte capturing device (100), by using
inkjet components such as ejection chambers (112), openings (114),
and ejectors (110) disposed within the ejection chambers (112),
enables low-volume dispensing of fluids.
[0034] FIG. 1C is a cross-sectional diagram of the analyte
capturing device (100) taken along the line A-A in FIG. 1A and
depicts the flow of an analyte-containing solution through the
analyte capturing device (100). As described above, a solution is
loaded into the analyte capturing device (100) and fills the
chamber (104). The analyte-adhering beads (116) having a diameter
greater than the microfluidic channels in the first substrate (108)
cannot pass to the microfluidic section and therefore aggregate in
the chamber (104).
[0035] As described above, the beads (116) are components that
draw, or adsorb, the analyte to their surface. For example, the
beads (116) may be formed of silica, alumina, a polymer, or other
material. The beads (116) may or may not have a surface treatment
that draws the analyte. The surface treatment may be specific to
the analyte of interest. For example, amino groups could be added
to the surface of the beads (116). These amino groups acquire a
proton and thereby become positively charged, making them
attractive to negatively charged DNA molecules.
[0036] In another example, complex proteins may be added to the
beads (116) with complementary proteins on the analyte. As such,
the proteins will attract one another and the analyte will
aggregate on the beads (116). In some examples, the
analyte-adhering beads (116) may have a diameter of between 5 and
20 microns, which may be larger than the diameter of the
microfluidic channels.
[0037] In one example, the activation of the fluid ejection device
(106) creates a fluid flow past the analyte-adsorbing beads (116).
As the solution passes the beads (116), analyte is captured
therein, and the remaining solution may be expelled as waste
through the opening (114) of the fluid ejection device (106). In
another example, a carrier fluid includes the beads (116). In this
example, adsorption of the analyte on the beads (116) occurs
upstream. In this example, the beads (116) are captured in the
chamber (104), and the fluid ejection devices (106) work to expel
waste fluid. That is, in either example, the analytes in the
solution are separated from the carrier fluid.
[0038] In some examples, the solution may include a lysis buffer
which breaks down the cell membrane/walls such that the analyte in
the cell can be collected. In this example, the lysis solution
forms part of the carrier fluid that is expelled through the fluid
ejection device (106).
[0039] Once separated from the carrier fluid, the analyte can then
be passed downstream. For example, once all the carrier fluid has
been removed, an elution buffer can be passed through the chamber
(104). The elution buffer works to break down the bonds that adhere
the analyte to the beads (116). The fluid ejection device (106) can
then be activated again to draw fluid, i.e., the elution buffer
with analyte, from the chamber (104) and out the opening (114) onto
a desired surface, or into another chamber of a larger system
wherein the analyte can be further analyzed.
[0040] Accordingly, the present analyte capturing device (100)
provides a large volume, i.e., on the order of 0.01 to 10
microliters, where analyte-adhering beads (116) are captured to
filter out the analyte from the rest of the solution. Using such a
large volume enables the capturing of more beads (116). More
captured beads (116) increases the overall ability to capture
analytes from the solution. The larger volume also enables the use
of larger analyte-adhering beads (116), such as those having a
diameter of between 5-20 microns. Larger analyte-adhering beads
(116) reduce the fluidic resistance of the system. That is, smaller
analyte-adhering beads (116) packed more tightly together increase
the fluid resistance such that greater pressures are needed to
drive the fluid through the volume. By comparison, larger
analyte-adhering beads (116) reduce the fluid resistance, such that
less pressure is required to drive the fluid. Using a lower
pressure 1) may increase the longevity and throughput of the
system, 2) is less complex, and 3) allows the use of smaller, less
invasive driving mechanisms.
[0041] FIG. 2 is a flow diagram of a method (200) for analyte
capturing with the analyte capturing device (FIG. 1A, 100),
according to another example of the principles described herein.
According to the method, analyte-adsorbing beads (FIG. 1C, 116) are
received (block 201) into a mesofluidic bead-capturing chamber
(FIG. 1A, 104). That is, as described above an analyte capturing
device (FIG. 1A, 100) includes a chamber (FIG. 1A, 104) that is on
a mesoscale. As a specific example, the second substrate (FIG. 1,
102) in which the chamber (FIG. 1A, 104) is formed may have a
thickness of between 100 and 775 microns. A reservoir of fluid
feeds fluid to this chamber (FIG. 1A, 104). The fluid in the
reservoir may be a solution that includes an analyte, a carrier
fluid, and analyte-adsorbing beads (FIG. 1C, 116) that draw the
analyte from the solution.
[0042] The microfluidic ejection device (FIG. 1A, 106) is then
activated. Doing so generates (block 202) flow through the
mesofluidic chamber (FIG. 1A, 104).
[0043] With a flow generated (block 202), the carrier fluid can be
expelled (block 203). That is, the operation of the microfluidic
ejection device (FIG. 1A, 106) expels the waste fluid, i.e., the
carrier fluid and extraneous components, out of the analyte
capturing device (FIG. 1A, 100). Such expelling may be onto a waste
surface or into a waste container.
[0044] The method (200) as described herein allows for the
separation of analyte from the carrier fluid. Specifically, the
carrier fluid is expelled as waste and the analyte is retained by
the beads (FIG. 1C, 116). Such a separation increases the
concentration of the analyte for further analysis. Accordingly, the
analyte capturing device (FIG. 1A, 100) as described herein
provides a simple and effective way to separate, and concentrate an
analyte within a solution.
[0045] FIGS. 3A-3C are diagrams of an analyte capturing device
(100) with fluid ejection devices (106), according to another
example of the principles described herein. Specifically, FIG. 3A
is a top view of the analyte capturing device (100) and FIGS. 3B
and 3C are cross-sectional views of the analyte capturing device
(100).
[0046] In this example, the analyte capturing device (100) includes
the second substrate (102) in which a bead-capturing chamber (104)
is formed and also includes fluid ejection devices (106). However,
in this example, the bead capturing chamber (104) includes multiple
bead-capturing holes (318) disposed beneath the chamber (104). For
simplicity, a single instance of a bead-capturing hole (318) is
indicated with a reference number. The bead-capturing holes (318)
serve to capture the analyte-adsorbing beads (FIG. 2, 116) as fluid
flows therethrough. The additional material between the holes (318)
may add to the mechanical rigidity of the second substrate (102).
For example, when the second substrate (102) is thinner, it may be
more susceptible to mechanical failure. Accordingly, the material
between the holes (318) increase the rigidity of the second
substrate (102). In this example, the holes (318) may be any size,
for example between tens of microns to a few hundred microns.
Moreover, while FIG. 3A depicts a particular orientation of certain
holes (318) with a certain diameter. Any number, any orientation,
and any-sized holes (318) may be used, in some examples with the
holes (318) having different sizes.
[0047] FIG. 3B is a cross-section of the analyte capturing device
(100) depicted in FIG. 3A. Specifically, FIG. 3B is a
cross-sectional diagram taken along the line B-B in FIG. 3A. FIG.
3B clearly depicts the holes (318-1, 318-2) as they feed multiple
fluid ejection devices (106-1, 106-2). Feeding multiple fluid
ejection devices (106) via mesofluidic holes (318) may allow for
faster solution processing, That is, rather than passing fluid to
just one fluid ejection device (106), fluid can be passed to
multiple fluid ejection devices (106-1, 106-2). While FIG. 3B
depicts two holes (318-1, 318-2) passing solution to two fluid
ejection devices (106-1, 106-2), each hole (318) may be coupled to
any number of fluid ejection devices (106). The holes (318) may be
of any size, for example, the holes (318) may have diameters of
between 5 and 80 microns. In this example, as has been described
above, the beads (116) may be sized such that they cannot pass into
the microfluidic structures of the first substrate (108).
[0048] FIG. 3C depicts yet another example using holes (318)
coupled to the chamber (104). In this example, a thin silicon
membrane (320) is placed at the bottom of the chamber (104). This
membrane (320) is perforated such that fluid may pass through, but
the beads (116) do not on account of their larger diameter. Use of
the membrane (320) as described herein maintains the beads (116)
further away from the microscopic fluid ejection devices (106) such
that they do not impede the flow of fluid into, or through, the
microfluidic structures. In some examples, the membrane (320) may
be formed of a silicon material or SU8 and may be between 3 and 20
micrometers thick.
[0049] FIG. 4 is a cross-sectional diagram of an analyte capturing
device (100) with fluid ejection devices (106), according to
another example of the principles described herein. As in examples
above, the analyte capturing device (100) includes a first
substrate (108), a second substrate (104), a bead-capturing chamber
(104), and fluid ejection device(s) (106). In this example, the
analyte capturing device (100) further includes an analyte channel
(422) in the first substrate (108). Through this analyte channel
(422), the analyte, following capture, is passed to another
component of the fluid analytic system. For example, once the
carrier fluid has been expelled, the elution buffer described above
is inserted into the bead-capturing chamber (104) to remove the
analyte from the analyte-adsorbing beads (116), This may be done
by, for example, altering the pH, changing electrical charge,
and/or heating the beads (116).
[0050] In this example, a driving mechanism can direct the fluid
flow through the analyte chamber (422) as opposed to the fluid
ejection device (106). For example, a pump may be disposed at some
point along the analyte chamber (422), or in some examples, at the
end of the analyte chamber (422). At a predetermined time, this
pump or other driving mechanism could be activated to draw the
analyte and elution buffer through the analyte channel (422) and
away from the fluid ejection device (106). In one specific example,
the fluid may be drawn to another chamber or component to further
analyze and/or process the fluid. Doing so may be beneficial in
that it does not expose the analyte to environment conditions,
which may tarnish or otherwise contaminate the analyte.
[0051] FIG. 5 is a diagram of a method (500) for analyte capturing
with the analyte capturing device (FIG. 1A, 100), according to
another example of the principles described herein. According to
the method (500), analyte-adsorbing beads (FIG. 1C, 116) are
received (block 501) in a mesofluidic bead-capturing chamber (FIG.
1A, 104) and a flow generated (block 502). Excess carrier fluid is
then expelled (block 503) out of the analyte capturing device (FIG.
1A, 100). These operations may be performed as described above in
connection with FIG. 2.
[0052] Then, as described above, the analyte may be separated from
the analyte-adsorbing beads (FIG. 1C, 116). This may be performed
by drawing (block 504) an elution buffer through the
analyte-adsorbing beads (FIG. 1C, 116), which at this stage have
analytes adhered thereon. As described above, the elution buffer
breaks down the bonds that adhere the analyte to the
analyte-adsorbing beads (FIG. 1C, 116).
[0053] Following removal from the analyte-adsorbing beads (FIG. 1C
116), the analyte is then drawn (block 505) from the bead-capturing
chamber (FIG. 1A, 104). This may occur in a number of different
ways. For example, the fluid ejection device (FIG. 1A, 106) could
be activated to expel the analyte and the elution buffer from the
analyte capturing device (FIG. 1A, 100) through the opening (FIG.
1B, 114). In this example, such an operation may be conducted after
the entirety of the carrier fluid has been expelled. Such an
example may allow for the analyte to be deposited on any type of
surface or container that is external and separate from the analyte
capturing device (FIG. 1A, 100).
[0054] In another example, a chamber pump, or some other driving
mechanism is activated to draw (block 505) the analyte and elution
buffer from the bead-capturing chamber (FIG. 1A, 104) through an
analyte channel (FIG. 4, 422). In this example, the analyte may
travel to another component of the analyte processing system. Using
an analyte channel (FIG. 4, 422) in this fashion, prevents the
analyte from contact with the environment or users, which may be
undesirable.
[0055] FIG. 6 is a cross-sectional diagram of an analyte capturing
device (100) with fluidic ejection devices (106), according to
another example of the principles described herein. As in other
examples, the analyte capturing device (100) includes a first
substrate (108) with a fluid ejection device (106) formed therein
and a second substrate (102) with a bead-capturing chamber (FIG.
1A, 104) formed therein. In this example, the analyte capturing
device (100) includes a third substrate (624) having an opening
larger than the bead-capturing chamber (FIG. 1A, 104), This third
substrate (624) opening allows for even a greater volume into which
analyte-adsorbing beads (116) are collected. That is, the
bead-capturing chamber (FIG. 1A, 104) by itself may have a volume
of 0.01 to 10 microliters. In this example, the size and shape of
the opening in the third substrate (624) may increase the volume to
upwards of 100 microliters. The increased volume allows for an even
larger quantity of analyte-adsorbing beads (116) to be captured
therein and further reduces the fluidic resistance as the beads
(116) may be less tightly packed. In some examples, the third
substrate (624) may be formed of any material including another
silicon layer, a plastic, a ceramic, or a composite layer.
[0056] FIG. 7 is a top view of an analyte capturing device (100),
according to another example of the principles described herein. To
accommodate the capture of more beads (FIG. 1C, 116) thus even
further increasing the efficacy of analyte concentration, the
analyte capturing device (100) may include multiple bead-capturing
chambers (104). While FIG. 7 depicts two bead-capturing chambers
(104-1, 104-2), the analyte capturing device (100) may include any
number of bead-capturing chambers (104). Using multiple
bead-capturing chambers (104) also increases the flow rate of the
solution through the analyte capturing device (100), which
increased flow rate also decreases processing times.
[0057] In some examples, the different chambers (104-1, 104-2) may
have different dimensions, shapes, and/or profiles. Using chambers
(104-1, 104-2) with different parameters increases the
customization available on an analyte capturing device (100). For
example, the different chambers (104-1, 104-2) may be used to
analyze different solutions. Thus, the present analyte capturing
device (100) provides for customized and tailored chemical
analysis.
[0058] In summary, using such an analyte capturing device 1)
enables analyte concentration via analyte-adsorbing beads; 2)
enables separation of the beads with adhered analyte thereon from a
carrier fluid; 3) includes a mesoscale volume to hold the
analyte-adsorbing beads, the larger volume allowing for a greater
quantity of analyte-adsorbing beads; and 4) facilitates the user of
larger analyte-adsorbing beads, reducing the fluidic resistance of
the system and thus enhancing the analyte concentration operation.
However, the devices disclosed herein may address other matters and
deficiencies in a number of technical areas.
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