U.S. patent application number 16/303095 was filed with the patent office on 2019-10-03 for microfluidic device for fluid mixture.
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 Ning GE, Alexander GOVYADINOV, Diane R HAMMERSTAD, Pavel KORNILOVICH, David MARKEL, Viktor SHKOLNIKOV, Erik D TORNIAINEN.
Application Number | 20190299176 16/303095 |
Document ID | / |
Family ID | 60912950 |
Filed Date | 2019-10-03 |
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United States Patent
Application |
20190299176 |
Kind Code |
A1 |
MARKEL; David ; et
al. |
October 3, 2019 |
MICROFLUIDIC DEVICE FOR FLUID MIXTURE
Abstract
Examples include microfluidic devices. Example microfluidic
devices comprise a first microfluidic channel, a second
microfluidic channel, and microfluidic output channel fluidly
coupled to the first microfluidic channel and the second
microfluidic channel via a fluid junction. The example device
comprises a first fluid actuator disposed in the first microfluidic
channel to actuate to thereby pump a first fluid into the
microfluidic output channel, and the example device comprises a
second fluid actuator disposed in the second microfluidic channel
to actuate to pump a second fluid into the microfluidic output
channel. The first fluid actuator and the second fluid actuator are
to actuate to thereby pump a fluid mixture of the first fluid and
the second fluid into the microfluidic output channel.
Inventors: |
MARKEL; David; (Corvallis,
OR) ; KORNILOVICH; Pavel; (Corvallis, OR) ;
TORNIAINEN; Erik D; (Corvallis, OR) ; GOVYADINOV;
Alexander; (Corvallis, OR) ; SHKOLNIKOV; Viktor;
(Palo Alto, CA) ; HAMMERSTAD; Diane R; (Corvallis,
OR) ; GE; Ning; (Palo Alto, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P. |
Houston |
TX |
US |
|
|
Assignee: |
Hewlett-Packard Development
Company, L.P.
Houston
TX
|
Family ID: |
60912950 |
Appl. No.: |
16/303095 |
Filed: |
June 30, 2017 |
PCT Filed: |
June 30, 2017 |
PCT NO: |
PCT/US2017/040418 |
371 Date: |
November 19, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/US2016/041586 |
Jul 8, 2016 |
|
|
|
16303095 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01F 13/0059 20130101;
B01F 2215/0036 20130101; G01N 35/1095 20130101; B01F 15/0416
20130101; B01F 2215/0037 20130101; B01L 3/5027 20130101; B01L
2300/1827 20130101; F04B 19/006 20130101; B01L 2300/0867 20130101;
B41J 2/1433 20130101; B81B 1/00 20130101; F04B 19/00 20130101; B01D
15/166 20130101; B41J 2/175 20130101; B01L 3/50273 20130101; B01L
2400/082 20130101; B01F 15/0258 20130101; B01L 2400/0415 20130101;
B01F 13/0064 20130101; B01L 2400/0487 20130101; B01L 2200/06
20130101; B01F 15/0243 20130101; B01L 2400/0439 20130101; B01L
2400/0442 20130101; B01F 15/0408 20130101 |
International
Class: |
B01F 13/00 20060101
B01F013/00; B01F 15/04 20060101 B01F015/04; B41J 2/14 20060101
B41J002/14; B01L 3/00 20060101 B01L003/00 |
Claims
1. A microfluidic device comprising: a first microfluidic channel;
a second microfluidic channel; a microfluidic output channel
fluidly coupled to the first microfluidic channel and the second
microfluidic channel at a fluid junction; a first fluid actuator
disposed in the first microfluidic channel, the first fluid
actuator to actuate to thereby pump a first fluid into the
microfluidic output channel; and a second fluid actuator disposed
in the second microfluidic channel, the second fluid actuator to
actuate to thereby pump a second fluid into the microfluidic output
channel, and the first fluid actuator and second fluid actuator to
actuate to thereby pump a fluid mixture of the first fluid and the
second fluid into the microfluidic output channel.
2. The microfluidic device of claim 1, further comprising: a first
fluid input fluidly coupled to the first microfluidic channel to
input the first fluid; a second fluid input fluidly coupled to the
second microfluidic channel to input the second fluid; and a
microfluidic chamber fluidly coupled to the microfluidic output
channel to store the fluid mixture.
3. The microfluidic device of claim 1, wherein the first fluid and
the second fluid have at least one different fluid characteristic,
the at least one different fluid characteristic comprising at least
one of: vapor pressure, temperature, viscosity, surface tension,
and heat of vaporization, and the first microfluidic channel and
the second microfluidic channel have at least one different
microfluidic channel characteristic, the at least one different
microfluidic channel characteristic comprising at least one of:
channel width, microfluidic channel cross-sectional area,
microfluidic channel geometry, microfluidic channel length, channel
surface roughness.
4. The microfluidic device of claim 1, further comprising: a
controller coupled to the first fluid actuator and the second fluid
actuator, the controller to: selectively actuate the first fluid
actuator and the second fluid actuator.
5. The microfluidic device of claim 4, wherein the controller to
selectively actuate the first fluid actuator and the second fluid
actuator comprises the controller to: actuate the first fluid
actuator according to first actuation characteristics; and actuate
the second fluid actuator according to second actuation
characteristics, wherein the first actuation characteristics and
the second actuation characteristics differ with respect to at
least one of frequency of actuation, duration of actuation, number
of pulses of actuation, phase offset of actuation, and intensity of
actuation.
6. The microfluidic device of claim 4, wherein the controller is to
selectively actuate the first fluid actuator and the second fluid
actuator asynchronously such that the fluid mixture comprises a
first concentration of the first fluid and a second concentration
of the second fluid.
7. The microfluidic device of claim 4, further comprising: at least
one fluid sensor, wherein the controller is further to: detect a
flow rate with the at least one fluid sensor, wherein the
controller is to selectively actuate at least one of the first
fluid actuator and the second fluid actuator based at least in part
on the flow rate.
8. The microfluidic device of claim 7, wherein the at least one
fluid sensor comprises at least one of: a first fluid sensor
disposed in the first microfluidic channel, a second fluid sensor
disposed in the second microfluidic channel, and a third fluid
sensor disposed in the microfluidic output channel.
9. (canceled)
10. The microfluidic device of claim 1, wherein the microfluidic
output channel is fluidly coupled to at least one of: a
microfluidic reaction chamber, an ejection chamber; a
chromatography column, and an optical detection chamber.
11. The microfluidic device of claim 1, wherein the first fluid
actuator is to pump the first fluid towards the fluid junction at a
first flow rate, the microfluidic device further comprising: a
third fluid actuator disposed in the first microfluidic channel to
actuate to thereby pump the first fluid towards the fluid junction
at a second flow rate.
12. The microfluidic device of claim 1, wherein the first fluid
actuator corresponds to a first inertial pump disposed in the first
microfluidic channel, the second fluid actuator corresponds to a
second inertial pump disposed in the second microfluidic channel,
and each of the first fluid actuator of the first inertial pump and
the second fluid actuator of the second inertial pump are thermal
resistors.
13. A microfluidic device comprising: a first microfluidic channel;
a second microfluidic channel; a microfluidic output channel that
is fluidly coupled to the first microfluidic channel and the second
microfluidic channel at a fluid junction; a first at least one
fluid actuator disposed in the first microfluidic channel, the
first at least one fluid actuator to actuate to thereby pump a
first fluid into the microfluidic output channel; a second at least
one fluid actuator disposed in the second microfluidic channel, the
second at least one fluid actuator to actuate to thereby pump a
second fluid into the microfluidic output channel, and the first at
least one fluid actuator and the second at least one fluid actuator
to asynchronously actuate to thereby pump fluid into the
microfluidic output channel to thereby pump a fluid mixture of the
first fluid and the second fluid into the microfluidic output
channel.
14. (canceled)
15. The microfluidic device of claim 13, wherein the first at least
one fluid actuator comprises a first set of fluid actuators, the
microfluidic device further comprising: a controller coupled to
each fluid actuator of the first set of fluid actuators, the
controller to: actuate a particular fluid actuator of the first set
of fluid actuators to cause the particular fluid actuator to pump a
first volume of the first fluid into the microfluidic output
channel; and actuate the particular fluid actuator and at least one
other fluid actuator of the first set of fluid actuators
synchronously to cause the particular fluid actuator and the at
least one other fluid actuator to pump a second volume of the first
fluid into the microfluidic output channel.
16. The microfluidic device of claim 13, further comprising: a
third microfluidic channel that is fluidly coupled to the
microfluidic output channel at the fluid junction; a third at least
one fluid actuator to actuate to thereby pump a third fluid into
the microfluidic output channel, the third at least one fluid
actuator to asynchronously actuate with the first at least one
fluid actuator and the second at least one fluid actuator, the
third at least one fluid actuator to pump the third fluid into the
microfluidic output channel such that the fluid mixture includes
the third fluid.
17-22. (canceled)
23. A method of a microfluidic device comprising: pumping a fluid
mixture including a first fluid and a second fluid into a
microfluidic output channel by: pumping, with a first fluid
actuator disposed in a first microfluidic channel, the first fluid
in the first microfluidic channel into the microfluidic output
channel via a fluid junction that fluidly couples the first
microfluidic channel and the microfluidic output channel; and
pumping, asynchronous with pumping the first fluid with the first
fluid actuator, pumping and with a second fluid actuator disposed
in a second microfluidic channel, the second fluid in the second
microfluidic channel into the microfluidic output channel via the
fluid junction that fluidly couples the second microfluidic channel
and the microfluidic output channel.
24-26. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of International
Patent Application No. PCT/US2016/041586, filed on Jul. 8, 2016,
titled "Microfluidic Device for Fluid Mixture," which is
incorporated herein by reference in its entirety.
BACKGROUND
[0002] Microfabrication involves the formation of structures and
various components on a substrate (e.g., silicon chip, ceramic
chip, glass chip, etc.). Examples of microfabricated devices
include microfluidic devices. Microfluidic devices include
structures and components for conveying, processing, and/or
analyzing fluids.
DRAWINGS
[0003] FIG. 1 provides a diagram of some components of an example
microfluidic device.
[0004] FIGS. 2A-G provide diagrams of operation of some components
of an example microfluidic device.
[0005] FIGS. 3A-C provide diagrams of some components of example
microfluidic devices.
[0006] FIGS. 4A-B provide diagrams of some components of example
microfluidic devices.
[0007] FIG. 5 provides a diagram of some components of an example
microfluidic device.
[0008] FIGS. 6A-B provide diagrams of some components of example
microfluidic devices.
[0009] FIG. 7 provides a diagram of some components of an example
microfluidic device.
[0010] FIG. 8 provides a diagram of some components of an example
microfluidic device.
[0011] FIGS. 9A-C provide diagrams of some components of example
microfluidic devices.
[0012] FIG. 10 provides a block diagram of some components of an
example microfluidic device.
[0013] FIG. 11 provides a flowchart that illustrates a sequence of
operations that may be performed by an example microfluidic
device.
[0014] FIG. 12 provides a flowchart that illustrates a sequence of
operations that may be performed by an example microfluidic
device.
[0015] FIG. 13 provides a flowchart that illustrates a sequence of
operations that may be performed by an example microfluidic
device.
[0016] FIG. 14 provides a flowchart that illustrates a sequence of
operations that may be performed by an example microfluidic
device.
[0017] FIG. 15 provides a flowchart that illustrates a sequence of
operations that may be performed by an example microfluidic
device.
[0018] FIG. 16 provides a flowchart that illustrates a sequence of
operations that may be performed by an example microfluidic
device.
[0019] 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.
DESCRIPTION
[0020] Examples provided herein include devices, methods, and
processes for microfluidic devices. Some example microfluidic
devices include lab-on-a-chip devices (e.g., polymerase chain
reaction devices, chemical sensors, etc.), fluid ejection devices
(e.g., inkjet printheads, fluid analysis devices, etc.), and/or
other such microdevices having microfluidic structures and
associated components. Examples described herein may comprise
microfluidic channels and fluid actuators disposed therein, where
the microfluidic channels may be fluidly coupled together, and the
fluid actuators may be actuated to dispense nanoliter and picoliter
scale volumes of various fluids.
[0021] Example devices may comprise a first microfluidic channel, a
second microfluidic channel, and a microfluidic output channel. The
first microfluidic channel and the second microfluidic channel may
be fluidly coupled to the microfluidic output channel at a fluid
junction. A first fluid actuator may be disposed in the first
microfluidic channel, and a second fluid actuator may be disposed
in the second microfluidic channel. The first fluid actuator is to
actuate to thereby pump a first fluid into the microfluidic output
channel, and the second fluid actuator is to actuate to thereby
pump a second fluid into the microfluidic output channel. By
selectively actuating the first and second fluid actuators, it will
be appreciated that a fluid mixture that includes at least the
first fluid and the second fluid may be pumped into the
microfluidic output channel.
[0022] As will be appreciated, examples provided herein may be
formed by performing various microfabrication and/or micromachining
processes on a substrate to form and/or connect structures and/or
components. The substrate may comprise a silicon based wafer or
other such similar materials used for microfabricated devices
(e.g., glass, gallium arsenide, plastics, etc.). Examples may
comprise microfluidic channels, fluid actuators, and/or volumetric
chambers. Microfluidic channels and/or chambers may be formed by
performing etching, microfabrication processes (e.g.,
photolithography), or micromachining processes in a substrate.
Accordingly, microfluidic channels and/or chambers may be defined
by surfaces fabricated in the substrate of a microfluidic
device.
[0023] A fluid actuator, as used herein may correspond to an
inertial pump. Fluid actuators that may be implemented as inertial
pumps described herein may include, for example, thermal actuators,
piezo-membrane based actuators, electrostatic membrane actuators,
mechanical/impact driven membrane actuators, magnetostrictive drive
actuators, electrochemical actuators, other such microdevices, or
any combination thereof. In some examples, fluid actuators may be
formed in microfluidic channels by performing various
microfabrication processes.
[0024] In some examples, a fluid actuator may correspond to an
inertial pump. As used herein, an inertial pump corresponds to a
fluid actuator and related components disposed in an asymmetric
position in a microfluidic channel, where an asymmetric position of
the fluid actuator corresponds to the fluid actuator being
positioned less distance from a first end of a microfluidic channel
as compared to a distance to a second end of the microfluidic
channel. Accordingly, in some examples, a fluid actuator of an
inertial pump is not positioned at a mid-point of a microfluidic
channel. The asymmetric positioning of the fluid actuator in the
microfluidic channel facilitates an asymmetric response in fluid
proximate the fluid actuator that results in fluid displacement
when the fluid actuator is actuated. Repeated actuation of the
fluid actuator causes a pulse-like flow of fluid through the
microfluidic channel.
[0025] In some examples, an inertial pump includes a thermal
actuator having a heating element (e.g., a thermal resistor) that
may be heated to cause a bubble to form in a fluid proximate the
heating element. In such examples, a surface of a heating element
(having a surface area) may be proximate to a surface of a
microfluidic channel in which the heating element is disposed such
that fluid in the microfluidic channel may thermally interact with
the heating element. In some examples, the heating element may
comprise a thermal resistor with at least one passivation layer
disposed on a heating surface such that fluid to be heated may
contact a topmost surface of the at least one passivation layer.
Formation and subsequent collapse of such bubble may generate
circulation flow of the fluid. As will be appreciated, asymmetries
of the expansion-collapse cycle for a bubble may generate such flow
for fluid pumping, where such pumping may be referred to as
"inertial pumping." In other examples, a fluid actuator
corresponding to an inertial pump may comprise a membrane (such as
a piezo-electric membrane) that may generate compressive and
tensile fluid displacements to thereby cause fluid flow.
[0026] As will be appreciated, a fluid actuator may be connected to
a controller, and electrical actuation of a fluid actuator (such as
a fluid actuator of an inertial pump) by the controller may thereby
control pumping of fluid. Actuation of a fluid actuator may be of
relatively short duration. In some examples, the fluid actuator may
be pulsed at a particular frequency for a particular duration. In
some examples, actuation of the fluid actuator may be 1 microsecond
(.mu.s) or less. In some examples, actuation of the fluid actuator
may be within a range of approximately 0.1 microsecond (.mu.s) to
approximately 10 milliseconds (ms). In some examples described
herein, actuation of a fluid actuator comprises electrical
actuation. In such examples, a controller may be electrically
connected to a fluid actuator such that an electrical signal may be
transmitted by the controller to the fluid actuator to thereby
actuate the fluid actuator. Each fluid actuator of an example
microfluidic device may be actuated according to actuation
characteristics. Examples of actuation characteristics include, for
example, frequency of actuation, duration of actuation, number of
pulses per actuation, intensity or amplitude of actuation, phase
offset of actuation. As will be appreciated in some examples, at
least one actuation characteristic may be different for each fluid
actuator. For example, a first fluid actuator may be actuated
according to first actuation characteristics and a second fluid
actuator may be actuated according to second actuation
characteristics, where the actuation characteristics for a
respective fluid actuator may be based at least in part on a
desired concentration of a respective fluid in a fluid mixture, a
fluid characteristic of the respective fluid, a fluid actuator
characteristic, and/or other such characteristics or input/output
variables. For example, the first fluid actuator may be actuated a
first number of times and the second fluid actuator may be actuated
a second number of times such that a desired concentration of a
first fluid and a desired concentration of a second fluid are
present in a fluid mixture.
[0027] In some examples described herein, at least one dimension of
a microfluidic channel and/or capillary chamber may be of
sufficiently small size (e.g., of nanometer sized scale, micrometer
sized scale, millimeter sized scale, etc.) to facilitate pumping of
small volumes of fluid (e.g., picoliter scale, nanoliter scale,
microliter scale, milliliter scale, etc.). For example, some
microfluidic channels may facilitate capillary pumping due to
capillary force. In addition, examples may couple at least two
microfluidic channels to a microfluidic output channel via a fluid
junction. At least one fluid actuator may be disposed in each of
the at least two microfluidic channels, and the fluid actuators may
be selectively actuated to thereby pump fluid into the microfluidic
output channel.
[0028] The microfluidic channels may facilitate conveyance of
different fluids (e.g., liquids having different chemical
compounds, different concentrations, etc.) to the microfluidic
output channel. In some examples, fluids may have at least one
different fluid characteristic, such as vapor pressure,
temperature, viscosity, density, contact angle on channel walls,
surface tension, and/or heat of vaporization. It will be
appreciated that examples disclosed herein may facilitate mixing of
miscible fluids. Furthermore it will be appreciated that examples
disclosed herein may facilitate manipulation of small volumes of
liquids.
[0029] The fluid actuators of each microfluidic channel may be
selectively actuated to pump the different fluids into the
microfluidic output channel to thereby create a mixture of the
different fluids in the microfluidic output channel, where the
mixture may have desired concentrations of each different fluid.
Therefore, it will be appreciated that examples disclosed herein
may facilitate small volume (e.g., picoliter scale, nanoliter
scale, microliter scale, milliliter scale, etc.) mixing of at least
two fluids at various ratios/concentrations. In some examples, a
fluid mixture of a microfluidic output channel may include a first
fluid at a first concentration and a second fluid at a second
concentration. As will be appreciated, fluid actuators may be
correspondingly actuated in some examples to achieve the desired
fluid concentrations for the fluid mixture. In some examples, the
at least one fluid actuator of each microfluidic channel may be
actuated alternatively such that fluid from each respective channel
may be pumped into the microfluidic output channel alternatively.
In some examples, such pumping by actuation of fluid actuators may
be referred to as asynchronous actuation, where asynchronous
actuation describes that the fluid actuators may be actuated
alternatively, out-of-phase, not at the same time, etc.
[0030] Turning now to the figures, and particularly to FIG. 1, this
figure provides a diagram that illustrates some components of an
example microfluidic device 10. In this example, the microfluidic
device 10 comprises a first microfluidic channel 12, a second
microfluidic channel 14, and a microfluidic output channel 16. As
shown, the first microfluidic channel 12 and the second
microfluidic channel 14 are fluidly coupled to the microfluidic
output channel 16 at a fluid junction 18. As shown, the device 10
comprises a first fluid actuator 20 disposed in the first
microfluidic channel 12, and the device 10 comprises a second fluid
actuator 22 disposed in the second microfluidic channel 14.
[0031] In examples similar to the example of FIG. 1, the first
microfluidic channel may facilitate conveyance of a first fluid
from a first source (e.g., a fluid reservoir, a fluid input, etc.),
and the second microfluidic channel 14 may facilitate conveyance of
a second fluid from a second source (e.g., a fluid reservoir, a
fluid input, etc.). The fluid actuators 20, 22 may be actuated to
thereby pump the first fluid and/or the second fluid towards the
fluid junction 18 and into the microfluidic output channel 16. As
will be appreciated, by alternatively actuating the first fluid
actuator 20 and the second fluid actuator 22, examples may
selectively pump the first fluid and the second fluid into the
microfluidic output channel in discrete volumes. As will be
appreciated, actuation of the first fluid actuator 20 and the
second fluid actuator 22 may be based at least in part on a desired
ratio of the first fluid and the second fluid in the microfluidic
output channel. In addition, it may be appreciated that
characteristics of actuation of the first fluid actuator 20 and the
second fluid actuator 22 may correspond to a volume and/or flow
rate of the first fluid or the second fluid pumped into the
microfluidic output channel 16. Examples of characteristics of
actuation that may be varied to thereby control a volume, a flow
rate, and/or a concentration of a fluid pumped into the
microfluidic output channel include a frequency of actuation, a
duration (e.g., pulse width) of actuation, timing offset (e.g.,
phase offset) of actuation, number of pulses for actuation,
intensity/amplitude of actuation, and/or other such characteristics
of actuation.
[0032] For example, if a ratio of a fluid mixture for the
microfluidic output channel is 2:1 with regard to a first fluid to
a second fluid, some examples may actuate a first fluid actuator at
a first frequency to pump a first volume of the first fluid into
the microfluidic output channel, and a second fluid actuator may be
actuated at a second frequency to pump a second volume of the
second fluid into the microfluidic output channel such that the
first fluid and second fluid in the microfluidic output channel at
the ratio of 2:1. As another example, a first fluid actuator may be
actuated twice for every one actuation of the second fluid
actuator. As another example, a first fluid actuator may be
actuated for a longer duration (i.e., with a longer pulse width) as
compared to the second fluid actuator. Other examples may perform
some combination of such examples to cause a desired ratio of
fluids, a desired concentration of fluids, etc. to be pumped into
the microfluidic output channel.
[0033] In other examples, it will be appreciated that the fluid
actuators 20, 22 may be implemented in inertial pumps. As discussed
previously, the fluid actuators 20, 22 are positioned
asymmetrically in the microfluidic channels 12, 14. In this
example, the fluid actuators 20, 22 are disposed in the
microfluidic channels 12, 14 nearer (i.e., less distance) to the
fluid junction 18 as compared to the opposite ends of the
microfluidic channels 12, 14. Accordingly, the fluid actuators 20,
22 of FIG. 1 may be inertial pumps. In some examples that
incorporate inertial pumps, fluid mixing may be facilitated by the
alternatively correlated actuation of the inertial pumps disposed
on each side of the fluid junction. Therefore, examples including
inertial pumps may asynchronously pump fluid with each inertial
pump such that the pulse-like flow generated by the inertial pumps
causes a fluid mixture to be pumped into the microfluidic output
channel.
[0034] FIGS. 2A-G illustrate diagrams of operation of an example
microfluidic device 100 to pump a mixture of first fluid in a first
microfluidic channel 102 and a second fluid in a second
microfluidic channel 104 into a microfluidic output channel 106. As
shown, the first microfluidic channel 102, second microfluidic
channel, and the microfluidic output channel are fluidly coupled at
a fluid junction (not labeled). As shown, the microfluidic device
100 includes a first fluid actuator 108 disposed in the first
microfluidic channel 102 and a second fluid actuator 110 disposed
in the second microfluidic channel 104.
[0035] In FIG. 2A, the device may be at an initial state, in which
fluids have not been pumped into the microfluidic output channel
106. In FIG. 2B, the first fluid actuator 108 may be actuated
(which may also be referred to as "firing the actuator") two times
such that a first respective volume of the first fluid 120 is
pumped into microfluidic output channel 106, and it will be noted
that a second respective volume of the first fluid is pumped into
the second microfluidic channel 104. In FIG. 2C, the second fluid
actuator 110 may be actuated such that the second respective volume
of the first fluid 122 that was in the second microfluidic channel
104 in FIG. 2B is pumped into the microfluidic output channel 106.
In FIG. 2D, the second fluid actuator 110 may be actuated twice
such that a first respective volume of the second fluid 126 may be
pumped into the microfluidic output channel 106, and a second
respective volume of the second fluid 128 may be pumped into the
first microfluidic channel 102. In FIG. 2E, the first fluid
actuator 108 may be actuated once such that the second respective
volume of the second fluid 128 that was in the first microfluidic
channel 102 is pumped into the microfluidic output channel 106. In
FIG. 2F, the first fluid actuator may be actuated twice to thereby
pump a third respective volume of the first fluid 130 into the
microfluidic output channel 106, and a fourth respective volume of
the first fluid 132 may be pumped into the second microfluidic
channel 104. Therefore, in this example, the first fluid actuator
108 and the second fluid actuator 110 may be alternatively actuated
to thereby pump respective volumes 120-132 into the microfluidic
output channel 106. FIG. 2G illustrates the example operation of
the example device 100 where the first fluid actuator 108 and the
second fluid actuator 110 have been operated as described with
regard to FIGS. 2A-2F to thereby pump a mixture of the first fluid
and the second fluid into the microfluidic output channel 106. As
will be appreciated, in this example, the ratio of the first fluid
to the second fluid pumped into the microfluidic output channel is
approximately 1:1. However, other examples may pump at least two
fluids into a microfluidic output channel at a various ratios (and
therefore concentrations) based on a configuration and/or actuation
of fluid actuators implemented therein.
[0036] FIGS. 3A-C provide diagrams that illustrate some components
of example microfluidic devices. FIG. 3A illustrates an example
microfluidic device 200 comprising a first microfluidic channel 202
and a second microfluidic channel 204 fluidly coupled to a
microfluidic output channel 206 at a fluid junction 208. As shown
in this example, a first fluid actuator 210 is disposed in the
first microfluidic channel 202 a first distance 212 from the fluid
junction 208, and a second fluid actuator 214 is disposed in the
second microfluidic channel 204 a second distance 216 from the
fluid junction 208. In this example, the first distance 212 and the
second distance 216 may be different. As will be appreciated, the
different distances 212, 216 for the first fluid actuator 210 and
the second fluid actuator 214 to the fluid junction 208 may
facilitate a different flow rate and/or different volume of fluid
that each fluid actuator 210, 214 may pump into the microfluidic
output channel 206. As will be appreciated, examples similar to the
example of FIG. 3A may be described as having fluid actuators
asymmetrically disposed in microfluidic channels.
[0037] FIG. 3B illustrates an example microfluidic device 220
comprising a first microfluidic channel 222 and a second
microfluidic channel 224 fluidly coupled to a microfluidic output
channel 226 via a fluid junction 227. As shown, the device 220
comprises a first fluid actuator 228 disposed in the first
microfluidic channel 222 and a second fluid actuator 230 disposed
in the second microfluidic channel 224. In this example, the first
fluid actuator 228 is of a first size and the second fluid actuator
230 is of a second size, where the sizes are different. For
example, if the fluid actuators 228, 230 are thermal-based fluid
actuators, a thermal resistor of the first fluid actuator 228 may
be smaller in size (e.g., surface area) as compared to the thermal
resistor of the second fluid actuator 230. As another example, if
the fluid actuators 228, 230 are piezo-electric based fluid
actuators, a piezo-electric membrane of the first fluid actuator
228 may be smaller in size (e.g., surface area) as compared to the
piezo-electric membrane of the second fluid actuator. As will be
appreciated, a size of the fluid actuators 228, 230 may correspond
to a flow rate of fluid and/or volume of fluid that the fluid
actuator 228, 230 may pump when actuated. Accordingly, in this
example, the microfluidic device may pump a greater volume of a
second fluid with the second fluid actuator 230 when actuated as
compared to a volume of a first fluid pumped by actuation of the
first fluid actuator 228. Examples similar to the example of FIG.
3C may be described as having asymmetric fluid actuators.
[0038] FIG. 3C provides a diagram of some components of an example
microfluidic device 240 that comprises a first microfluidic channel
242 and a second microfluidic channel fluidly coupled to a
microfluidic output channel 246 via a fluid junction 248. In this
example, the device 240 comprises a first fluid actuator 250
disposed a first distance from the fluid junction 248 in the first
microfluidic channel 242, and the device 240 comprises a second
fluid actuator 252 disposed a second distance from the fluid
junction 248 in the second microfluidic channel 244. In addition,
the first fluid actuator 250 and the second fluid actuator 252 are
of different sizes. As discussed above with regard to FIGS. 3A and
3B, asymmetric positioning of the fluid actuators 250, 252 relative
to the fluid junction 248 and asymmetric fluid actuators 250, 252
may correspond to a respective volume of fluid that each fluid
actuator may pump into the microfluidic output channel 246. In
addition, the asymmetric positioning of the fluid actuators 250,
252 relative to the fluid junction 248 and asymmetric fluid
actuators 250, 252 may correspond to a flow rate at which each
fluid actuator 250, 252 may pump fluid into the microfluidic output
channel 246.
[0039] FIGS. 4A-B provide diagrams of some components of example
microfluidic devices. In FIG. 4A, the microfluidic device 260
comprises a first microfluidic channel 262, a second microfluidic
channel 264, and a microfluidic output channel 266 fluidly coupled
thereto via fluid junction 267, as described in other examples. In
this example, the device 260 includes a first set of fluid
actuators 268a-b disposed in the first microfluidic channel 262,
and the device includes a second set of fluid actuators 270a-d
disposed in the second fluid channel 264. For the first set of
actuators 268a-b, a first fluid actuator 268a is disposed a second
distance away from the fluid junction 267 and a second fluid
actuator 268b is disposed a first distance away from the fluid
junction 267, where the first distance is less than the second
distance. For the second set of fluid actuators 270a-d: a first
fluid actuator 270a is disposed a first distance from the fluid
junction 267; a second fluid actuator 270b is disposed a second
distance from the fluid junction 267; a third fluid actuator 270c
is disposed a third distance from the fluid junction 267; and a
fourth fluid actuator 270d is disposed a fourth distance from the
fluid junction 267. As shown in this example, for the second set of
fluid actuators 270a-d: the first distance is less than the second
distance; the second distance is less than the third distance; and
the third distance is less than the fourth distance. Accordingly,
the second set of fluid actuators 270a-d may be described as
arranged along a length of the second microfluidic channel 264.
[0040] In examples similar to the examples of FIG. 4A, it will be
appreciated that examples may actuate the fluid actuators of the
first set 268a-b individually or in combination to thereby
facilitate pumping of different volumes of fluid and/or pumping at
different flow rates. For example, the first fluid actuator 268a of
the first set 268a-b may be actuated to thereby pump a first volume
of a first fluid into the microfluidic output channel 266. The
second fluid actuator 268b of the first set 268a-b may be actuated
to thereby pump a second volume of the first fluid into the
microfluidic output channel 266. Both fluid actuators of the first
set 268a-b may be actuated concurrently (e.g., at the same time
and/or within in a short time-span) to thereby pump a third volume
of the first fluid into the microfluidic output channel 266.
Similarly, examples may actuate the fluid actuators of the second
set 270a-d individually and/or in combinations to thereby pump
different volumes of a second fluid into the microfluidic output
channel 266.
[0041] FIG. 4B provides a diagram that illustrates some examples of
a microfluidic device 280 that comprises a first microfluidic
channel 282, a second microfluidic channel 284, and a microfluidic
output channel 286 fluidly coupled thereto via a fluid junction
287, as described in other examples. In this example, the
microfluidic device 280 comprises a first set of fluid actuators
288a-c disposed in the first microfluidic channel 282 and along a
length of the first microfluidic channel 282. In this example,
similar to the example of FIG. 3B, a first fluid actuator 288a, a
second fluid actuator 288b, and a third fluid actuator of the first
set 288a-c are of different sizes. Therefore, in this example,
actuation of each fluid actuator of the first set 288a-c may pump a
different volume of a first fluid from the first microfluidic
channel 282 into the microfluidic output channel 286. In addition,
similar to the example of FIG. 3A, the distance of each fluid
actuator of the first set 288a-c may also correspond to a flow rate
of fluid and/or volume of fluid pumped due to actuation.
Furthermore, the device 280 comprises a second set of fluid
actuators 290a-b of different sizes disposed in the second
microfluidic channel 284, where each fluid actuator of the second
set 290a-b is a different distance from the fluid junction 287.
[0042] Accordingly, as illustrated in the examples of FIGS. 4A-B,
some example microfluidic devices may comprise a set of fluid
actuators disposed in and along a length of a microfluidic channel.
As will be appreciated a size of a respective fluid actuator as
well as a distance of a respective fluid actuator from the fluid
junction may be based at least in part on a volume of respective
fluid to be pumped, a flow rate of pumping for the respective
fluid, a ratio of the respective fluid and all other fluids to be
pumped into the microfluidic output channel, and/or a concentration
of the respective fluid and all other fluids to be pumped into the
microfluidic output channel. As will be appreciated, actuation of
the fluid actuators of each set of fluid actuators 288a-c, 290a-b
may be selective based on a volume of fluid to be pumped to the
microfluidic output channel, a ratio of a respective fluid to be in
a fluid mixture in the microfluidic output channel, a concentration
of each fluid to be in the fluid mixture, etc. Moreover, in
examples described herein, a single fluid actuator of a set may be
actuated or a combination of at least two fluid actuators of a set
may be actuated in a corresponding manner (e.g., concurrently,
synchronously, alternatively, etc.) such that pumping may occur at
different flow rates and/or different volumes of fluid may be
pumped.
[0043] FIG. 5 is a diagram that illustrates some components of an
example microfluidic device 300. In this example, the microfluidic
device 300 comprises a first microfluidic channel 302, a second
microfluidic channel 304, and a microfluidic output channel 306
fluidly coupled thereto via a fluid junction 307, as described in
other examples. In this example, the device 300 comprises a first
set of fluid actuators 308a-e disposed in the first microfluidic
channel 302 and a second set of fluid actuators 310a-f disposed in
the second microfluidic channel 304. In this example, the fluid
actuators of each set 308a-e, 310a-f are arranged adjacent to each
other along a length of the respective microfluidic channel 302,
304.
[0044] In examples similar to the example of FIG. 5, the
adjacently-arranged fluid actuators of a set may be described as a
fluid actuator array. In such examples, each fluid actuator of an
array may be actuated separately to cause a respective volume of
fluid to be pumped at a respective flow rate. Adjacent fluid
actuators (e.g., a first fluid actuator 308a and a second fluid
actuator 308b) may be actuated concurrently such that the adjacent
fluid actuators operate as a single fluid actuator that causes a
larger volume of fluid to be pumped into the microfluidic output
channel 306 at a higher flow rate as compared to operation of the
adjacent fluid actuators separately.
[0045] For example, if the fluid actuators of the first set 308a-e
correspond to thermal based fluid actuators, each fluid actuator
may comprise a thermal resistor of a particular surface area. By
actuating two of the fluid actuators concurrently, the two fluid
actuators may operate in a manner similar to a single fluid
actuator having the total surface area of the two fluid actuators
(e.g., double the particular surface area). As will be appreciated,
examples may selectively actuate: a single fluid actuator of the
first set 308a-e; at least two fluid actuators of the first set
308a-e; or all fluid actuators of the first set 308a-e to thereby
pump different volumes of fluid at different flow rates into the
microfluidic output channel 306. The fluid actuators of the second
set 310a-f may be operated similarly. In the example of FIG. 5, it
will be noted that the second set of fluid actuators 310a-f
comprises at least one fluid actuator 310f that is a different size
than other fluid actuators of the second set 310a-e. As discussed
in previous examples, size of a fluid actuator as well as position
(e.g., distance from the fluid junction) may correspond to a volume
of fluid to be pumped and/or a rate of flow of pumped fluid.
[0046] As will be appreciated, microfluidic devices may be
configured for a particular application (i.e., application
specific) such that a characteristics of a microfluidic device may
be based at least in part on a desired mixing ratio, a desired
concentration, a desired flow rate, and/or other such factors.
Example characteristics of some example microfluidic devices
include, for example, characteristics of fluid actuators, such as
size of fluid actuators, positioning of fluid actuators in
microfluidic channels, number of fluid actuators in a respective
channel, etc. Further example characteristics of a microfluidic
device that may vary based on application include characteristics
of the microfluidic channels implemented therein. Example
microfluidic channel characteristics include microfluidic channel
width, microfluidic channel cross-sectional area, microfluidic
channel geometry (e.g., cross-sectional shape), microfluidic
channel length, channel texture/surface roughness, etc.
[0047] FIG. 6A is a diagram of an example microfluidic device 350
that includes a first microfluidic channel 352, a second
microfluidic channel 354, and a microfluidic output channel 356
fluidly coupled thereto via a fluid junction. In this example, a
first fluid actuator 358 is disposed in the first microfluidic
channel 352, and a second fluid actuator 360 is disposed in the
second microfluidic channel 354. In this example, the first
microfluidic channel 352 has a channel width that is greater than a
microfluidic channel width of the second microfluidic channel 354.
Accordingly, a first volume of a first fluid pumped from the first
microfluidic channel 352 into microfluidic output channel 356 may
be greater than a second volume of a second fluid pumped from the
second microfluidic channel 354 into the microfluidic output
channel 356. Therefore, in some examples, a microfluidic channel
width may be based at least in part on a desired ratio of the first
fluid to the second fluid in a fluid mixture in the microfluidic
output channel 356.
[0048] FIG. 6B is a diagram of an example microfluidic device 370
that comprises a first microfluidic channel 372, a second
microfluidic channel 374, and a microfluidic output channel 376
fluidly coupled thereto via a fluid junction 377. The device
further comprises a first fluid actuator 378 disposed in the first
microfluidic channel 372 and a second fluid actuator 380 disposed
in the second microfluidic channel 374. As discussed in previous
examples, the microfluidic channels 372, 374 may be connected to
fluid reservoirs, fluid inputs, other fluid junctions, etc. In this
example, the first microfluidic channel 372 is illustrated as
fluidly connected to a first fluid input to input a first fluid,
and the second microfluidic channel 374 is fluidly connected to a
second fluid input 384 to input a second fluid. In this example, a
channel length 386 of the first microfluidic channel 372 is greater
than a channel length 388 of the second microfluidic channel
374.
[0049] While the examples illustrated in FIGS. 1-6B illustrate
microfluidic devices comprising two microfluidic channels, it will
be appreciated that other examples may comprise more than two
microfluidic channels. For example, referring to FIG. 7, this
figure provides a diagram of an example microfluidic device 400
that includes a first set of microfluidic channels 402a-c, a second
microfluidic channel 404, and a microfluidic output channel 406
that is fluidly coupled to the first set of microfluidic channels
402a-c and the second microfluidic channel 404 via a fluid junction
407. The device 400 includes a fluid actuator 408-414 disposed in
each microfluidic channel 402a-c, 404. In this example, the first
set of microfluidic channels 402a-c may convey a first fluid and
the second microfluidic channel 404 may convey a second fluid.
Accordingly, in this example, the first fluid may be pumped into
the microfluidic output channel in varying volumes based at least
in part on the actuation of the fluid actuators 410-414 disposed in
the first set of microfluidic channels 402a-c.
[0050] FIG. 8 provides a diagram of some components of an example
microfluidic device 450 that comprises a first microfluidic channel
452, a second microfluidic channel 454, a third microfluidic
channel 456, and a microfluidic output channel 458 fluidly coupled
to the first microfluidic channel 452, the second microfluidic
channel 454, and the third microfluidic channel 456 via a fluid
junction 459. The device 450 includes a fluid actuator 460-464
disposed in each microfluidic channel 452-456. Accordingly, in this
example, the first microfluidic channel 452 may convey a first
fluid; the second microfluidic channel 454 may convey a second
fluid; and the third microfluidic channel 456 may convey a third
fluid. Therefore, in this example, the microfluidic device may
selectively actuate the microfluidic actuators 460-464 of the
microfluidic channels 452-456 to thereby pump a fluid mixture of
the first fluid, second fluid, and third fluid into the
microfluidic output channel 458.
[0051] FIGS. 9A-C provide diagrams of some components of an example
microfluidic device 500. The example microfluidic device 500
comprises a first microfluidic channel 502, a second microfluidic
channel 504, and a microfluidic output channel fluidly coupled
thereto via a fluid junction. Furthermore, the device 500 includes
a fluid actuator 508-510 disposed in each microfluidic channel
502-504. In the example of FIG. 9A, the device 500 includes a first
fluid sensor 512 disposed in the first microfluidic channel 502,
and the device 500 includes a second fluid sensor 514 disposed in
the second fluid channel 504. In some examples, the flow sensors
512, 514 may be utilized to detect a flow rate for pumping of a
first fluid from the first microfluidic channel 512 or a second
fluid second microfluidic channel 504. Accordingly, it will be
appreciated that, based on the detected flow rates, a concentration
of the first fluid and the second fluid, a mixing ratio of the
first fluid and second fluid, and/or a volume of the first fluid
and second fluid may be determined for a fluid mixture in the
microfluidic output channel 506. In FIG. 9B, the microfluidic
device 500 comprises a fluid sensor 520 disposed in the
microfluidic output channel 506. Accordingly, in the example of
FIG. 9B, a flow rate may be determined for a fluid mixture in the
microfluidic output channel 506. In FIG. 9C, the example device 500
comprises fluid sensors 512, 514, 520 disposed in the first
microfluidic channel 502, the second microfluidic channel 504, and
the microfluidic output channel 506. In the examples shown in FIGS.
9A-C, the fluid sensors 512, 514 of the microfluidic channels 502,
504 is disposed between the fluid actuator 508, 510 and the fluid
junction. As will be appreciated, other examples may include fluid
sensors disposed at various positions in the microfluidic channels
and/or microfluidic output channel.
[0052] FIG. 10 provides a block diagram that illustrates some
components of an example microfluidic device 600. As discussed
previously, various structures/components (e.g., microfluidic
channels, capillary chambers, fluid inputs, fluid reservoirs, etc.)
may be formed/microfabricated in a substrate (e.g., a silicon wafer
portion, a glass wafer portion, etc.). In this example, the device
600 comprises a substrate 602 into which a first microfluidic
channel 604 and a second microfluidic channel 606 are formed. In
addition, the device 600 includes a microfluidic output channel 608
formed in the substrate 602 that is fluidly connected to the first
microfluidic channel 604 and the second microfluidic channel 606
via a fluid junction 609.
[0053] In this example, the first microfluidic channel 604 is
fluidly connected to a fluid input 610 (which, in the example, is
illustrated as a fluid reservoir) to input a first fluid that may
be conveyed to the microfluidic output channel 608 via the first
microfluidic channel 604. The second microfluidic channel 606 may
be fluidly connected to a fluid input 612 to input a second fluid
that may be conveyed to the microfluidic output channel 608 via the
second microfluidic channel 606. While the example device 600 is
illustrated with a fluid reservoir 610 and a fluid input 612, it
will be appreciated that in other examples, the microfluidic
channels may be connected to other fluid sources, such as fluid
reservoirs, fluid inputs, microfluidic reaction chambers, fluid
junctions, etc. The microfluidic device 600 includes a first fluid
actuator 614 disposed in the first microfluidic channel 604, and
the device includes a second fluid actuator 616 disposed in the
second microfluidic channel 606. Furthermore, the microfluidic
output channel 608 may be fluidly connected to a microfluidic
chamber 620, and the microfluidic chamber 620 may store the fluid
mixture. While not shown in this example, the microfluidic chamber
620 may comprise various other components and/or structures, such
as fluid ejectors and nozzles, heating elements, fluid analysis
sensors, optical detectors, microfluidic columns, and/or other such
components that may facilitate further processing and/or analysis
of a fluid mixture conveyed to the microfluidic chamber 620 from
the microfluidic output channel 608. Therefore, it will be
appreciated that the microfluidic chamber 620 may correspond to a
microfluidic reaction chamber, an ejection chamber, a
chromatography column, an optical detection chamber, or any
combination thereof.
[0054] In this example, the fluid actuators 614, 616 may be
electrically connected to a controller 630. While not shown other
components, such as fluid sensors, optical detectors, fluid
ejectors, etc. may be electrically connected to the controller 630.
Accordingly, the controller may electrically actuate these
components, and the controller may receive data in the form of
electrical signals from these components. For example, the
controller 630 may electrically actuate fluid actuators 614, 616 to
thereby cause the fluid actuators 614, 616 to pump fluid. As
another example, the controller may receive sensor data from the
fluid sensors that corresponds to a flow rate of a fluid.
[0055] While the term "controller" may be used herein, it will be
appreciated that a controller may comprise various types of data
processing resources. A controller may include, for example, at
least one hardware based processor. Similarly, a controller may
comprise one or more general purpose data processors and/or one or
more specialized data processors. For example, a controller may
comprise a central processing unit (CPU), an application-specific
integrated circuit (ASIC), and/or other such configurations of
logical components for data processing.
[0056] In some examples, such as the example of FIG. 10, the
controller 630 comprises a processing resource 632 and a memory
resource 634 that stores executable instructions 636. Execution of
instructions 636 may cause the controller and/or device to perform
functionalities, processes, and/or sequences of operations
described herein. Furthermore, in the examples, the memory resource
may comprise a machine-readable storage medium, which may be
referred to as a memory. The memory resource may represent random
access memory (RAM) devices as well as other types of memory (e.g.
cache memories, non-volatile memory devices, read-only memories,
etc.). A memory resource may include RAM, ROM, erasable
programmable read-only memory (EPROM), electrically erasable
programmable read-only memory, flash memory or other solid state
memory technology, or any other medium that may be used to store
executable instructions and information. Furthermore, the memory
resource 636 may be non-transitory.
[0057] In some examples, the controller may be externally located
(e.g., in a data processing system) and may be electrically
connected to components of an example microfluidic device via
electrical connections and conductive traces of the microfluidic
device. In other examples, the microfluidic device may comprise a
controller disposed on a common substrate and electrically
connected to components of the microfluidic device via conductive
traces.
[0058] FIGS. 11-16 provide flowcharts that provide example
sequences of operations that may be performed by an example
microfluidic device and/or a controller thereof to perform example
processes and methods. In some examples, the operations included in
the flowcharts may be embodied in a memory resource (such as the
example memory resource 634 of FIG. 10) in the form of instructions
that may be executable by a processing resource to cause the device
and/or controller to perform the operations corresponding to the
instructions.
[0059] As shown in FIG. 11, an example device may pump a first
fluid in a first microfluidic channel into a microfluidic output
channel with a first fluid actuator disposed in the first
microfluidic channel via a fluid junction (block 702). The
microfluidic device may pump a second fluid in a second
microfluidic channel into the microfluidic output channel with a
second actuator that is disposed in the second microfluidic channel
via a fluid junction (block 704), where actuation of the second
fluid actuator and the pumping thereby may be asynchronous with
actuation of the first fluid actuator and the pumping thereby. As
discussed previously, asynchronous may refer to the first fluid
actuator and the second fluid actuator being actuated at different
times. In some examples, the first fluid actuator may be actuated
at a first frequency and the second fluid actuator may be actuated
at a second frequency that is different than the first frequency.
In some examples, the first actuator and second actuator may be
actuated at a common frequency but phase shifted such that the
first actuator and second actuator are actuated in an alternating
manner.
[0060] By asynchronously pumping the first fluid and the second
fluid into the microfluidic output channel with the first fluid
actuator and the second fluid actuator, the example device thereby
pumps a fluid mixture that includes the first fluid and the second
fluid in the microfluidic output channel (block 706). As will be
appreciated, a ratio of the first fluid and the second fluid in the
fluid mixture may be based at least in part on fluid actuator
characteristics (e.g., fluid actuator size, fluid actuator position
in a respective microfluidic channel, number of fluid actuators,
etc.), microfluidic channel characteristics (e.g., microfluidic
channel length, microfluidic channel width, microfluidic channel
geometry, etc.), and/or actuation characteristics (e.g., frequency
of actuation, duration of actuation, number of pulses per
actuation, intensity of actuation, etc.). Furthermore, a
concentration and/or a volume of each fluid in the fluid mixture of
the microfluidic output channel may be similarly based on fluid
actuator characteristics, microfluidic channel characteristics,
and/or actuation characteristics. Furthermore, it will be
appreciated that examples may pump the fluid mixture into the
microfluidic output channel to thereby control a temperature and/or
pressure of the microfluidic device.
[0061] FIG. 12 provides a flowchart 750 that illustrates a sequence
of operations that may be performed by a controller (such as the
controller 630 of FIG. 10). As shown, the controller may actuate a
first fluid actuator disposed in a first microfluidic channel to
thereby pump a first fluid into a microfluidic output channel
(block 752). Asynchronous with actuation of the first fluid
actuator, the controller may actuate a second fluid actuator
disposed in a second microfluidic channel to thereby pump a second
fluid into the microfluidic output channel (block 754). As will be
appreciated, the controller may continue selective actuation of the
first and second fluid actuators to thereby pump a fluid mixture
including the first and second fluids into the microfluidic output
channel.
[0062] FIG. 13 provides a flowchart 800 that illustrates a sequence
of operations that may be performed by an example microfluidic
device and/or a controller thereof. The device may detect a flow
rate at a first microfluidic channel with a first fluid sensor
disposed in the first microfluidic channel (block 802). The device
may selectively actuate a first fluid actuator disposed in the
first microfluidic channel based at least in part on the flow rate
at the first microfluidic channel (block 804) to thereby pump a
first fluid into a microfluidic output channel fluidly connected to
the first microfluidic channel. As shown, the device may continue
detecting the flow rate at the first microfluidic channel and
selectively actuating the first fluid actuator based on the flow
rate at the first microfluidic channel. Concurrent with the
operations of blocks 802-804, the device may detect a flow rate at
a second microfluidic channel with a second fluid sensor disposed
in the second microfluidic channel (block 806). The device may
selectively actuate a second fluid actuator disposed in the second
microfluidic channel based at least in part on the flow rate at the
second microfluidic channel (block 808). As shown, the example
device may continue detecting the flow rate at the second
microfluidic channel and selectively actuating the second fluid
actuator based on the flow rate at the second microfluidic
channel.
[0063] As will be appreciated, in the example of FIG. 13, the
device may selectively actuate the first fluid actuator and the
second fluid actuator in an alternating manner. In some examples,
such actuation timing may be described as asynchronous.
Furthermore, some examples may detect flow rates associated with
pumping of fluids into the microfluidic output channel, and, in
such examples, further pumping of such fluids may be based at least
in part on the flow rates. Accordingly, in these examples, a
feedback loop may be implemented such that further actuation of
fluid actuators may be adjusted based on such flow rates, where it
will be appreciated that the flow rates may correspond to mixing
ratios of fluids in the fluid mixture of the microfluidic output
channel, a concentration of each fluid in the fluid mixture, and/or
a volume of each fluid in the fluid mixture.
[0064] FIG. 14 provides a flowchart 850 that illustrates a sequence
of operations that may be performed by an example microfluidic
device and/or a controller thereof. In this example, based on a
desired concentration of a first fluid and a second fluid to be in
a fluid mixture of a microfluidic output channel (block 852), the
microfluidic device may pump, with a first fluid actuator disposed
in a first microfluidic channel, a first fluid into the
microfluidic output channel based at least in part on the
concentration of the first fluid to be in the fluid mixture (block
854), and the device may pump, with a second fluid actuator
disposed in a second microfluidic channel, a second fluid into the
microfluidic output channel based at least in part on the
concentration of the second fluid to be in the fluid mixture (block
856). As will be appreciated, pumping of fluid corresponds to
actuation of a fluid actuator. Accordingly, actuation of the first
fluid actuator may be based at least in part on the concentration
of the first fluid to be in the fluid mixture, and actuation of the
second fluid actuator may be based at least in part on the
concentration of the second fluid to be in the mixture.
[0065] FIG. 15 provides a flowchart 900 that illustrates a sequence
of operations that may be performed by an example microfluidic
device. In this example, the microfluidic device may comprise a
first set of fluid actuators disposed in a first microfluidic
channel and a second fluid actuator disposed in a second
microfluidic channel. The microfluidic device may pump a first
volume of a first fluid with a first subset of the fluid actuators
of the first set into the microfluidic output channel (block 902).
The microfluidic device may pump a second fluid with the second
fluid actuator into the microfluidic output channel (block 904).
The example device may pump a second volume of the first fluid into
the microfluidic output channel with a second subset of fluid
actuators of the first set (block 906). Accordingly, in examples in
which at least two fluid actuators are disposed in a common
microfluidic channel, such examples may selectively actuate each
fluid actuator individually or in various combinations to cause
pumping of different volumes of fluid.
[0066] FIG. 16 provides a flowchart 950 that illustrates an example
sequence of operations that may be performed by an example
microfluidic device and/or a controller thereof. In this example,
the microfluidic device may comprise a first set of fluid actuators
disposed in a first microfluidic channel and a second fluid
actuator disposed in a second microfluidic channel. As shown, the
device actuates a first fluid actuator of the first set of fluid
actuators to pump a first volume of a first fluid into the
microfluidic output channel (block 952). The device detects a flow
rate of the first fluid into the microfluidic output channel (block
954). The device actuates the second fluid actuator to pump a
second fluid into the microfluidic output channel (block 956). The
device detects a flow rate of the second fluid into the
microfluidic output channel (block 958). The device determines a
second volume of the first fluid to pump into the microfluidic
output channel based at least in part on the flow rate of the first
fluid and/or the flow rate of the second fluid (block 960). The
device actuates the first fluid actuator and at least one other
fluid actuator of the first set to pump the determined second
volume of the first fluid into the microfluidic output channel
(block 962).
[0067] Accordingly, the examples described herein provide examples
of a microfluidic device in which fluids may be pumped into a fluid
mixture at a desired concentration. In these examples, microfluidic
channels may facilitate input of at least two different fluids.
Fluid actuators disposed in the microfluidic channels may
facilitate precise pumping of discrete volumes of such fluids into
a microfluidic output channel to thereby pump a fluid mixture into
the microfluidic channel. As will be appreciated, example devices
as described herein may facilitate manipulation of small volumes of
fluid (e.g., approximately 1 nL to approximately 1 pL). Because
examples described herein facilitate manipulation and mixing of
such small volumes of fluid, examples may be implemented for
precision fluid mixing devices and/or as components in fluid
processing devices.
[0068] In addition, while various examples are described herein,
elements and/or combinations of elements may be combined and/or
removed for various examples contemplated hereby. For example, the
example operations provided herein in the flowcharts of FIGS. 11-16
may be performed sequentially, concurrently, or in a different
order. Moreover, some example operations of the flowcharts may be
added to other flowcharts, and/or some example operations may be
removed from flowcharts. Furthermore, in some examples, various
components of the example systems of FIGS. 1-10 may be removed,
and/or other components may be added.
[0069] The preceding description has been presented to illustrate
and describe examples of the principles described. This description
is not intended to be exhaustive or to limit these principles to
any precise form disclosed. Many modifications and variations are
possible in light of the above disclosure.
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