U.S. patent application number 10/908014 was filed with the patent office on 2008-08-14 for a flow control system of a cartridge.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. Invention is credited to Cleopatra Cabuz, Eugen Cabuz.
Application Number | 20080195020 10/908014 |
Document ID | / |
Family ID | 36678510 |
Filed Date | 2008-08-14 |
United States Patent
Application |
20080195020 |
Kind Code |
A1 |
Cabuz; Cleopatra ; et
al. |
August 14, 2008 |
A FLOW CONTROL SYSTEM OF A CARTRIDGE
Abstract
An apparatus having a disposable cytometer cartridge containing
pumps, pressure chambers, reservoirs, flow sensors, flow channels,
and microfluidic circuits with fluid operations on the cartridge.
The circuits may include mesopumps and mesovalves embedded in the
chip, card or cartridge. The apparatus may have multiple detecting,
analyzing and identification capabilities of blood or other fluids
of interest. The sample to be tested may be entered in the
disposable microfluidic cartridge which in turn is insertable in a
hand-holdable or portable cytometer instrument. This apparatus may
have significant application in biological warfare agent detection,
water analyses, environmental checks, hematology, and other
clinical and research fields.
Inventors: |
Cabuz; Cleopatra; (Eden
Prairie, MN) ; Cabuz; Eugen; (Eden Prairie,
MN) |
Correspondence
Address: |
HONEYWELL INTERNATIONAL INC.
101 COLUMBIA ROAD, P O BOX 2245
MORRISTOWN
NJ
07962-2245
US
|
Assignee: |
HONEYWELL INTERNATIONAL
INC.
Morristown
NJ
|
Family ID: |
36678510 |
Appl. No.: |
10/908014 |
Filed: |
April 25, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
10304773 |
Nov 26, 2002 |
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10908014 |
|
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|
09630924 |
Aug 2, 2000 |
6597438 |
|
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10304773 |
|
|
|
|
10980685 |
Nov 3, 2004 |
6968862 |
|
|
09630924 |
|
|
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|
10174851 |
Jun 19, 2002 |
6837476 |
|
|
10980685 |
|
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|
10340231 |
Jan 10, 2003 |
6889567 |
|
|
10174851 |
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|
09586093 |
Jun 2, 2000 |
6568286 |
|
|
10340231 |
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Current U.S.
Class: |
604/4.01 |
Current CPC
Class: |
B01L 2200/0636 20130101;
A61B 5/150221 20130101; B01L 2300/0816 20130101; B01L 2400/0633
20130101; G01N 15/1484 20130101; G01F 1/7086 20130101; B01L
2400/0655 20130101; A61B 5/150969 20130101; F16K 99/0051 20130101;
A61B 5/150343 20130101; B01L 2400/0481 20130101; G01N 2015/1486
20130101; A61B 5/150213 20130101; A61B 5/150022 20130101; B01L
3/5027 20130101; B01L 9/527 20130101; A61B 5/150229 20130101; B01L
2400/0487 20130101; A61B 5/150755 20130101; F16K 99/0015 20130101;
G01N 15/1404 20130101; G01N 15/1056 20130101 |
Class at
Publication: |
604/4.01 |
International
Class: |
A61M 37/00 20060101
A61M037/00 |
Claims
1. A flow control system comprising: a fluidic cartridge having at
least one flow channel; an electrostatically actuated valve
situated in at least one flow channel of the cartridge, wherein the
electrostatically actuated valve includes a valve cavity with a
movable diaphragm within the valve cavity, wherein the movable
diaphragm is actuated by an electrostatic force to open the
electrostatically actuated valve to allow flow through the at least
one flow channel and/or close the electrostatically actuated valve
to prevent flow through the at least one flow channel; a controller
connected to the electrostatically actuated valve for controlling
the opening and/or closing of the electrostatically actuated valve
during operation of the fluidic cartridge; and a flow sensor in
fluid communication with the at least one flow channel the flow
sensor measuring the velocity of fluid flow, and the controller
controlling the valve to achieve a desired fluid velocity in the at
least one flow channel.
2. The system of claim 1, wherein the electrostatically actuated
valve is a mesovalve.
3. A flow control system comprising: a fluidic cartridge having at
least one flow channel; a pump situated in the cartridge, the pump
in fluid communication with at least one flow channel of the
cartridge; a controller connected to the pump; and a flow sensor
situated in the cartridge and in fluid communication with the at
least one flow channel of the cartridge, the flow sensor providing
a flow signal representing the fluid velocity to the controller,
and the controller controlling the pump to achieve a desired flow
profile in the at least one flow channel of the cartridge.
4. The system of claim 3, wherein the pump is a bidirectional
pump.
5. (canceled)
6. The system of claim 3, wherein: the pump is a liquid pump; and
the flow sensor is a liquid flow sensor.
7. The system of claim 3, wherein the pump is gas pump.
8. The system of claim 7, wherein the pump is an electrostatically
actuated gas pump.
9. The system of claim 8, further comprising a reservoir fluidly
connected to gas pump.
10. The system of claim 9, wherein the flow sensor is fluidly
connected to the reservoir and electrically connected to the
controller.
11. The system of claim 3, further comprising: a buffer fluidly
connected to the pump; and a reservoir fluidly connected to the
buffer.
12. The system of claim 11, wherein the flow sensor is fluidly
connected to the reservoir.
13. The system of claim 12, wherein: the pump is a gas pump; and
the reservoir is a liquid reservoir.
14. The system of claim 3, further comprising: a pressure chamber
fluidly connected to the pump; and a reservoir fluidly connected to
the pressure chamber.
15. The system of claim 14, wherein the pressure chamber comprises:
an inlet valve connected to the controller; and a relief valve.
16. The system of claim 15, wherein: the pump is an
electrostatically actuated pump; and the valves are
electrostatically actuated valves.
17. The system of claim 15, wherein the flow sensor is fluidly
connected to the reservoir and electrically connected to the
controller.
18. The system of claim 3, further comprising: a pressure chamber
fluidly connected to the pump; and a liquid reservoir fluidly
connected to the pressure chamber.
19. The system of claim 18, wherein the fluidic cartridge has a
thickness of less than 10 mm and an area less than 150 cm2.
20. The system of claim 18, wherein the pressure chamber comprises:
an inlet valve connected to the controller; and a pressure sensor
connected to the controller.
21. The system of claim 20, wherein the flow sensor is fluidly
connected to the reservoir and electrically connected to the
controller.
22. The system of claim 21, further comprising a buffer fluidly
connected between the pump and the pressure chamber.
23. The system of claim 22, wherein: the pump is a gas pump; and
the reservoir is a liquid reservoir.
24. The system of claim 23, wherein: the pump is an
electrostatically actuated pump; and the valve is an
electrostatically actuated valve.
25. The system of claim 21, wherein the flow sensor is situated off
of the cartridge.
Description
[0001] This present application is a continuation-in-part of U.S.
patent application No. 10/304,773, filed Nov. 26, 2002, which is a
continuation-in-part of U.S. patent application Ser. No.
09/630,924, filed Aug. 2, 2000, now U.S. Pat. No. 6,597,438 B1, and
claims the benefit thereof. Also, this present application is a
continuation-in-part of U.S. patent application Ser. No.
10/980,685, filed Nov. 3, 2004, which is a division of U.S. patent
application Ser. No. 10/174,851, filed Jun. 19, 2002, now U.S. Pat.
No. 6,837,476, and claims the benefit thereof. Also, this present
application is a continuation-in-part of U.S. patent application
Ser. No. 10/340,231, filed Jan. 10, 2003, which is a division of
U.S. patent application Ser. No. 09/586,093, filed Jun. 2, 2000,
now U.S. Pat. No. 6,568,286 B1, and claims the benefit thereof. All
of the above-mentioned patent documents are incorporated herein by
reference.
[0002] The present invention is related to U.S. patent application
Ser. No. 10/905,995, filed Jan. 28, 2005, by Cabuz et al., entitled
"Mesovalve Modulator", and incorporated herein by reference. Also,
the present invention is related U.S. patent application Ser. No.
11/018,799, filed Dec. 21, 2004, by Cabuz et al., entitled "Media
Isolated Electrostatically Actuated Valve", and incorporated herein
by reference. These applications are owned by the same entity that
owns the present invention.
[0003] The present invention is also related to U.S. Pat. No.
6,549,275 B1, issued Apr. 15, 2003 to Cabuz et al., and entitled
"Optical Detection System for Flow Cytometry"; U.S. Pat. No.
6,382,228 B1, issued May 7, 2002 to Cabuz et al., and entitled
"Fluid Driving System for Flow Cytometry"; U.S. Pat. No. 6,700,130
B2, issued Mar. 2, 2004 to Fritz, and entitled "Optical Detection
System for Flow Cytometry"; U.S. Pat. No. 6,729,856 B2, issued May
4, 2004, to Cabuz et al., and entitled "Electrostatically Actuated
Pump with Elastic Restoring Forces"; U.S. Pat. No. 6,255,758 B1,
issued Jul. 3, 2001, to Cabuz et al., and entitled "Polymer
Microactuator Array with Macroscopic Force and Displacement"; U.S.
Pat. No. 6,240,944 B1, issued June 5, 2001 to Ohnstein et al., and
entitled "Addressable Valve Arrays for Proportional Pressure or
Flow Control"; U.S. Pat. No. 6,179,586 B1, issued Jan. 30, 2001 to
Herb et al., and entitled "Dual Diaphragm, Single Chamber
Mesopump"; and U.S. Pat. No. 5,836,750, issued Nov. 17, 1998 to
Cabuz, and entitled "Electrostatically Actuated Mesopump Having a
Plurality of Elementary Cells"; all of which are incorporated
herein by reference. These patents are owned by the same entity
that owns the present invention.
BACKGROUND
[0004] The present invention relates generally to flow cytometers.
More particularly, the present invention relates to portable flow
cytometers that sense optical properties of microscopic biological
particles or components in a flow stream.
[0005] Flow cytometry is a technique that is used to determine
certain physical and chemical properties of microscopic biological
particles or components by sensing certain optical properties of
the particles or components. To do so, for instance, the particles
may be arranged in single file using hydrodynamic focusing within a
sheath fluid. The particles are then individually interrogated by a
light beam. Each particle scatters the light beam and produces a
scatter profile. The scatter profile is often identified by
measuring the light intensity at different scatter angles. Certain
physical and/or chemical properties of each particle can then be
determined from the scatter profile.
[0006] Flow cytometry is currently used in a wide variety of
applications including hematology, immunology, genetics, food
science, pharmacology, microbiology, parasitology, oncology,
biological agent detection, and environmental science, to name a
few. A limitation of many commercially available flow cytometer
systems is that they are relatively large bench top instruments
that must remain in a central laboratory environment. Accordingly,
the use of such flow cytometers is often not available in remote
locations or for continuous hematological monitoring.
SUMMARY
[0007] The present invention can overcome many of the disadvantages
of the related art by providing a highly miniaturized portable and
wearable apparatus (e.g., cytometer) that is usable at remote
locations, such as at home or in the field. The apparatus may
incorporate fluid devices and operations on a disposable cartridge,
chip or card, with optical and electrical interfaces external to
the cartridge. Such an apparatus may help improve healthcare of
patients by providing detailed individual hematological evaluation
and uncovering statistical trends. By detecting an infection early,
the infection may be more readily treatable. The apparatus may also
be used in non-medical applications such as those in various
environmental and industrial areas.
[0008] In military applications, the apparatus may be a portable
miniaturized cytometer of the present invention may help save lives
by providing early detection of infection due to biological agents.
It is known that expanded activity in the biological sciences has
increased the probability of accidental exposure to dangerous
biological agents. The ease of manufacturing such agents also
raises a serious threat to their use by terrorists, regional powers
or developing third world nations. The lack of safeguards in
international agreements outlawing biological warfare, and
compelling evidence that those agreements may have been violated,
reinforces the need for a strong capability for biological defense.
Pre-exposure detection of pathogen agents, as well as post-exposure
detection of incipient infections may be used cooperatively to
ensure efficient protection during biological warfare.
[0009] As part of the body's natural defense against antigens, the
white blood cell count increases at the onset of infection. There
are several types of white blood cells including neutrophils,
lymphocytes, monocytes, eosinophils and basofils. Lymphocytes
create antibodies that attack the invaders and mark them for
destruction by the neutrophils and macrophages. In an individual
without chronic diseases (such as tuberculosis or cancer), an
increase in the percentage of lymphocytes in the overall white cell
count is an indication of a viral infection. On the other side, an
increase in the percentage of the neutrophils is an indication of a
developing bacterial infection. Through counting of neutrophils and
lymphocytes, a clear infection warning can be issued with
differentiation between viral or bacterial causes.
[0010] The first clinical symptoms of infection from some bacterial
agents such as bacillus anthrax appear after one to six days. In 99
percent of the cases, patients showing symptoms from anthrax cannot
be treated, and will most likely die. However, if treatment is
given before the first symptoms appear, most patients can be
successfully treated. Accordingly, it would be highly desirable to
provide an early alert and potential therapeutic intervention for
hematologic abnormalities before symptoms occur. In many cases,
such an early alert and treatment may greatly improve the outcome
for many patients.
BRIEF DESCRIPTION OF THE DRAWING
[0011] FIG. 1 is a perspective view of an illustrative portable
cytometer in accordance with the present invention;
[0012] FIG. 2 is a schematic view of the illustrative portable
cytometer of FIG. 1;
[0013] FIG. 3 is a more detailed schematic diagram showing the
cytometer of FIG. 2 with the cover not yet depressed;
[0014] FIG. 4 is a more detailed schematic diagram showing the
cytometer of FIG. 2 with the cover depressed;
[0015] FIG. 5 is a schematic diagram showing an illustrative manual
fluid driver having a bulb and check valve;
[0016] FIG. 6 is a graph showing proportional pressure control of
an addressable array of microvalves;
[0017] FIG. 7 is a schematic diagram showing the formation of a
flow stream by a flow mechanism block 88 of FIG. 3;
[0018] FIG. 8 is a schematic diagram showing an array of light
sources and an array of light detectors for analysis of the core
stream of FIG. 7;
[0019] FIG. 9 is a graph showing the light intensity produced along
the light source axis of FIG. 8;
[0020] FIG. 10 is a schematic diagram showing an illustrative light
source and detector pair of FIG. 8;
[0021] FIG. 11 is a schematic diagram showing three separate arrays
of light sources and detectors, each positioned along a different
light source axis that is slightly rotated relative to the central
flow axis of the flow stream of FIG. 7;
[0022] FIG. 11a is a three dimensional illustration of an array of
light sources and an array of light detectors positioned along a
light source and detector axis that is not parallel to the central
flow axis of the flow stream;
[0023] FIG. 12 is a schematic diagram showing an illustrative light
source and detector pair of the first array shown in FIG. 11;
[0024] FIG. 13 is a schematic diagram showing an illustrative light
source and detector pair of the second array shown in FIG. 11;
[0025] FIG. 14 is a schematic diagram showing an illustrative light
source and detector pair of the third array shown in FIG. 11;
[0026] FIG. 15 is a perspective view of an illustrative example of
the miniaturized portable cytometer adapted to be worn around the
wrist;
[0027] FIG. 16 reveals a disposable cytometer cartridge containing
the pumps, pressure chambers, reservoirs, flow sensors, and a flow
mechanism with a flow channel on the cartridge;
[0028] FIG. 17a is another version of the cartridge where the
liquid devices and operations occur on cartridge;
[0029] FIG. 17b is like the version of FIG. 17a except that the
processor is situated in the cartridge;
[0030] FIGS. 18a-18d show a various stages of fluid flow in a
microfluidic circuit in cartridge or chip; and
[0031] FIGS. 19a and 19b reveal an application in a microfluidic
circuit of mesopumps and mesovalves embedded in a chip, card or
cartridge 14;
[0032] FIGS. 20a and 20b reveal an illustrative example of a
mesovalve in a closed state and an open state, respectively;
[0033] FIG. 21 is a diagram of a the cartridge having a mesovalve
with open loop control;
[0034] FIG. 22 is a diagram of a fluid pump on a cartridge with
open loop control;
[0035] FIG. 23 shows a liquid pump and flow sensor on a cartridge,
with closed loop control;
[0036] FIG. 24 shows a gas pump and flow sensor on a cartridge,
with closed loop control;
[0037] FIG. 25 shows a gas pump, buffer and liquid reservoir on a
cartridge, with open loop control;
[0038] FIG. 26 is similar to FIG. 25, except the components are off
the cartridge;
[0039] FIG. 27 is similar to FIG. 25, except it also includes a
flow sensor and closed loop control;
[0040] FIG. 28 is similar to FIG. 27, except the components are off
the cartridge;
[0041] FIG. 29 is similar to FIG. 27, except it has the flow sensor
off the cartridge and has a pressure chamber;
[0042] FIG. 30 is similar to FIG. 29, except the flow sensor is on
the cartridge;
[0043] FIG. 31 is similar to FIG. 30, except the pressure chamber
has a different configuration; and
[0044] FIG. 32 is similar to FIG. 31, except the components are
shown as off the cartridge.
[0045] FIG. 33 is similar to FIG. 30, except the components are
shown off the cartridge.
DESCRIPTION
[0046] In an illustrative example of the present invention, a
portable miniaturized cytometer may be provided for identifying
and/or counting selected particles in a fluid sample such as a
blood sample. One illustrative miniaturized portable cytometer
includes a fluid receiver for receiving the fluid sample. One or
more reservoirs are provided for storing supporting fluids such as
lyse and sheath fluids. For many commercial flow cytometer systems,
a precision fluid driving system is used for providing precise
pressures to the fluids. A limitation of this approach is that
precision fluid driving systems can be bulky, complex and may
require significant power.
[0047] To avoid many of these limitations, an illustrative example
uses a non-precision fluid driver that is controlled by a closed
loop feedback path. The non-precision fluid driver is coupled to
the fluid receiver and the various supporting fluid reservoirs, and
applies separate pressures to the sample fluid and the supporting
fluids. To control the velocity of the sample fluid and the
supporting fluids, one or more valves are coupled to the fluid
driver. The valves are used to regulate the non-precision pressures
that are applied to the sample fluid and the supporting fluids by
the non-precision fluid driver.
[0048] To complete the feedback loop, flow sensors are provided
downstream of the fluid driver to measure the fluid velocity of the
sample fluid and the supporting fluids. A controller or processor
receives the signals from the flow sensors, and adjusts the
appropriate valves so that the desired fluid velocities of the
sample fluid and supporting fluids are achieved. The flow sensors
are preferably thermal anemometer type flow sensors.
[0049] In one illustrative example, the non-precision fluid driver
is manually powered. A manually powered fluid driver may include,
for example, a bulb with check valve or a plunger. In either case,
the manually generated pressure is preferably provided to a first
pressure chamber. A first valve is then provided for controllably
releasing the pressure in the first pressure chamber to a second
pressure chamber. A second valve may be provided in the second
pressure chamber for controllably venting the pressure in the
second pressure chamber. The controller opens the first valve when
the fluid flow in the downstream fluid stream drops below a first
predetermined value and opens the second valve when the fluid flow
in the downstream fluid stream increases above a second
predetermined value. Each valve is preferably an array of
electrostatically actuated microvalves that are individually
addressable and controllable.
[0050] The controlled sample fluid and supporting fluids are
provided to a fluidic circuit. The fluidic circuit may perform
hydrodynamic focusing, which causes the desired particles to fall
into single file along a core stream surrounded by a sheath fluid.
One or more light sources or light source arrangements provide
light through the flow stream, and one or more light detectors or
light detector arrangements detect the scatter profile and
fluorescence of the particles in the flow stream. An arrangement
may have one or more light sources and/or one or more light
detectors. An arrangement may include a single optical device or
element or an array of such items. A processing block uses the
output signals from the light detectors to identify and/or count
selected particles in the core stream.
[0051] The miniaturized portable cytometer may be provided in a
housing sufficiently small to be appropriately and comfortably
"wearable" on a person. In one illustrative example of the
invention, the housing is sized similar to a wrist watch. The
wearable housing may include, for example, a base, a cover, and a
hinge that secures the base to the cover. The non-precision fluid
driver and regulating valves may be incorporated into the cover,
while the fluid reservoirs, flow sensors and fluidic circuit may be
incorporated into a removable cartridge (or "card" as it may
sometimes be referred to) that is inserted into the housing. The
fluidic circuit may dilute the blood sample, perform red cell
lysing, and perform hydrodynamic focusing for flow and core stream
formation. The light sources may be situated in either the base or
the cover, and aligned with the flow stream of the removable
cartridge. The light detectors are preferably provided generally
opposite the light sources. The processor and batteries may be
provided in either the base or the cover of the housing.
[0052] The light source may include one or a linear array of first
light sources along a first light source axis. The first light
source axis may be rotated relative to the central axis of the flow
stream. A lens may be provided adjacent each light source to focus
the light at the particles in the core stream. A detector or set of
light detectors may then be placed in-line with the light source or
each of the light sources. Such an arrangement can be used to
determine, for example, the alignment and width of the core stream
within the flow stream. If the core stream of particles is not in
proper alignment, the controller can adjust the fluid velocity of
the sample fluid or one of the supporting fluids to bring the core
stream into alignment. The light detector or set of light detectors
may also be used to detect the velocity and size of each particle,
as well as the number of particles.
[0053] Another light source or set of the light sources may be
provided along second light source axis. A lens may be provided
adjacent each light source to focus the light at the particles in
the core stream. A second detector or set of light detectors may
then be placed on either side of the in-line position of each light
source for measuring the small angle scattering (SALS) produced by
selected particles in the flow stream.
[0054] The second light source or set of light sources may also be
used in conjunction with the first set of light sources to
determine the time-of-flight or velocity of the particles in the
flow stream. By knowing the velocity of the particles, small
variations in the flow rate caused by the fluid driver can be
minimized or removed by the controller.
[0055] A third light source or set of light sources may be provided
along a third light source axis. A lens may be provided adjacent
each light source to provide collimated light to the flow stream.
An annular light detector or detectors may then be placed opposite
the light source or light sources for measuring the forward angle
scattering (FALS) produced by the selected particles in the flow
stream. Each of the first, second and third light sources or sets
of light sources may include an array of lasers such as vertical
cavity surface emitting lasers (VCSELs) fabricated on a common
substrate. Each of the first, second and third detectors or sets of
light detectors may include a photo detector or an array of photo
detectors such as p-i-n photodiodes, GaAs photodiodes with
integrated FET circuits, resonant cavity photo detectors (RCPDs),
or any other suitable light detectors.
[0056] The selected particles are preferably neutrophils and/or
lymphocytes white blood cells. By examining the scatter profile of
each particle, the miniaturized portable cytometer of the present
invention identifies and counts the neutrophils and lymphocytes in
a blood sample, and provides a clear infection warning with
differentiation between viral and bacterial causes.
[0057] Another part of the invention uses of fluorescence to
further identify and analyze various white cells. Antibodies may be
associated with particular white blood cells. The antibodies have
markers or tags attached to them. These white blood cells may be
impinged with light which causes their associated markers or tags
to fluoresce and emit light. The light may be collected, filtered
as needed, and directed to one or more photo detectors. This
detection may be used to identify and monitor specific subclasses
of white cells and blood-based proteins, among other things.
[0058] This miniaturized portable cytometer may have two optical
detection subsystems--scattering and fluorescing. It also has a low
power electronic system, a compact fluid driving system, and may
use direct/unprocessed blood samples and disposable microfluidic
cartridges,
[0059] FIG. 1 is a perspective view of an illustrative miniaturized
portable cytometer in accordance with the present invention. The
cytometer is generally shown at 10, and includes a housing 12 and a
removable or replaceable cartridge 14. The illustrative housing 12
includes a base 16, a cover 18, and a hinge 20 that attaches the
base 16 to the cover 18. The base 16 includes light sources 22a and
22b, associated optics and the necessary electronics for operation
of the cytometer. The cover 12 includes a manual pressurizing
element, pressure-chambers with control microvalves, and light
detectors 24a and 24b with associated optics.
[0060] The removable cartridge 14 preferably receives a sample
fluid via a sample collector port 32. A cap 38 may be used to
protect the sample collector port 32 when the removable cartridge
14 is not in use. The removable cartridge 14 may perform blood
dilution, red cell lysing, and hydrodynamic focusing for core
formation. The removable cartridge 14 may be constructed similar to
the fluidic circuits available from Micronics Technologies, some of
which are fabricated using a laminated structure with etched
channels.
[0061] The removable structure or cartridge 14 is inserted into the
housing when the cover 18 is in the open position. The removable
cartridge 14 may include holes 26a and 26b for receiving
registration pins 28a and 28b in the base 16, which help provide
alignment and coupling between the different parts of the
instrument. The removable cartridge 14 also preferably includes
transparent flow stream windows 30a and 30b, which are in alignment
with the arrays of the light sources 22a and 22b, and light
detectors 24a and 24b. When the cover is moved to the closed
position, and the system is pressurized, the cover 18 provides
controlled pressures to pressure receiving ports 34a, 34b, and 34c
in the removable cartridge 14 via pressure providing ports 36a, 36b
and 36c, respectively.
[0062] To initiate a test, the cover 18 is lifted and a new
cartridge 14 is placed and registered onto the base 16. A blood
sample is introduced into the sample collector 32. The cover 18 is
closed and the system is manually pressurized. Once pressurized,
the instrument performs a white blood cell cytometry measurement.
The removable cartridge 14 may provide blood dilution, red cell
lysing, and hydrodynamic focusing for core formation. The light
sources 22a and 22b, light detectors 24a and 24b and associated
control and processing electronics may perform differentiation and
counting of white blood cells based on light scattering fluorescent
signals. Rather than using a hinged construction for the housing
12, it is contemplated that a sliding cartridge slot or any other
suitable construction may be used.
[0063] FIG. 2 is a schematic view of the illustrative cytometer of
FIG. 1. As above, the base 16 may include light sources 22a and
22b, associated optics and the necessary control and processing
electronics 40 for operation of the cytometer. The base 16 may also
include a battery 42 for powering the cytometer. The cover 12 is
shown having a manual pressurizing element 44, pressure-chambers
46a, 46b and 46c with control microvalves, and light detectors 24a
and 24b with associated optics.
[0064] The removable cartridge 14 may receive a sample fluid via
the sample collector port 32. When pressurized by the cover 18, the
removable cartridge 14 may perform blood dilution, red cell lysing,
and hydrodynamic focusing for core formation in the present device.
Once formed, the core may be provided down a flow stream path 50,
which passes the flow stream windows 30a and 30b of FIG. 1. The
light sources 22a and 22b, and associated optics in the base
provide light through and to the core stream via the flow stream
windows 30a and 30b. The light detectors 24a and 24b, and
associated optics receive scattered and non-scattered light from
the core, also via the flow stream windows 30a and 30b,
respectively. The controller or processor 40 receives output
signals from the detectors 24a and 24b, and differentiates,
identifies and counts selected white blood cells that are present
in the core stream.
[0065] It is contemplated that the removable cartridge 14 may
include a fluid control block 48 for helping control the velocity
of each of the fluids. In the illustrative example, the fluid
control block 48 includes flow sensors for sensing the velocity of
the various fluids and reports the velocities to the controller or
processor 40. The controller or processor 40 may then adjust the
microvalves associated with pressure-chambers 46a, 46b and 46c to
achieve the desired pressures and thus desired fluid velocities for
proper operation of the cytometer.
[0066] Because blood and other biological waste can spread disease,
the removable cartridge 14 preferably has a waste reservoir 52
downstream of the flow stream windows 30a and 30b. The waste
reservoir 52 receives and stores the fluid of the flow stream in
the removable cartridge 14. When a test is completed, the removable
cartridge may be removed and disposed of, preferably in a container
compatible with biological waste.
[0067] FIG. 3 is a more detailed schematic diagram showing the
cytometer of FIG. 2 with the cover 18 not yet depressed. FIG. 4 is
a more detailed schematic diagram showing the cytometer of FIG. 2
with the cover depressed. The cover 18 is shown having a manual
pressurizing element 44, pressure-chambers 46a, 46b and 46c, and
control microvalves generally shown at 60. The light sources and
detectors are not shown in these Figures.
[0068] There are three pressure chambers 46a, 46b and 46c, one for
each fluid to be pressurized. In the illustrative example, pressure
chamber 46a provides pressure to a blood sample reservoir 62,
pressure chamber 46b provides pressure to a lyse reservoir 64, and
pressure chamber 46c provides pressure to a sheath reservoir 66.
The size and shape of each pressure chamber 46a, 46b and 46c may be
tailored to provide the desired pressure characteristics to the
corresponding fluid.
[0069] Pressure chamber 46a includes a first pressure chamber 70
and a second pressure chamber 72. A first valve 74 is provided
between the first pressure chamber 70 and the second pressure
chamber 72 for controllably releasing the pressure in the first
pressure chamber 70 to a second pressure chamber 72. A second valve
76, in fluid communication with the second pressure chamber 72,
controllably vents the pressure in the second pressure chamber 72.
Each valve is preferably an array of electrostatically actuated
microvalves that are individually addressable and controllable, as
described in, for example, co-pending U.S. patent application Ser.
No. 09/404,560, entitled "Addressable Valve Arrays for Proportional
Pressure or Flow Control", and incorporated herein by reference.
Pressure chambers 46b and 46c include similar valves to control the
pressures applied to the lyse reservoir 64 and sheath reservoir 66,
respectively. Alternatively, each valve may be an array of
electrostatically actuated microvalves that are pulse modulated
with a controllable duty cycle to achieve a controlled "effective"
flow or leak rate.
[0070] The removable cartridge 14 has pressure receiving ports 34a,
34b, and 34c for receiving the controlled pressures from the cover
18. The controlled pressures are provided to the blood reservoir
62, lyse reservoir 64 and sheath reservoir 66, as shown. The lyse
reservoir 64 and sheath reservoir 66 are preferably filled before
the removable cartridge 14 is shipped for use, while the blood
reservoir 62 is filled from sample collector port 32. A blood
sample may be provided to the sample collector port 32, and through
capillary action, the blood sample is sucked into the blood
reservoir 62. Once the blood sample is in the blood reservoir 62,
the cover 18 may be closed and the system may be pressurized.
[0071] A flow sensor may be provided in-line with each fluid prior
to hydrodynamic focusing. Each flow sensor 80, 100 and 102 may
measure the velocity of the corresponding fluid. The flow sensors
may be thermal anemometer type flow sensors and/or microbridge type
flow sensor. Microbridge flow sensors are described in, for
example, U.S. Pat. No. 4,478,076, U.S. Pat. No. 4,478,077, U.S.
Pat. No. 4,501,144, U.S. Pat. No. 4,651,564, U.S. Pat. No.
4,683,159, and U.S. Pat. No. 5,050,429, all of which are
incorporated herein by reference. An output signal from each flow
sensor 80, 100 and 102 is provided to controller or processor
40.
[0072] The controller or processor 40 opens the first valve 74 when
the velocity of the blood sample drops below a first predetermined
value and opens the second valve 76 when Page 15 of 78 the velocity
of the blood sample increases above a second predetermined value.
Valves 84, 86, 94 and 96 operate in a similar manner to control the
velocities of the lyse and sheath fluids.
[0073] During operation, and to pressurize the system, the manual
pressurizing element 44 is depressed. In the example shown, the
manual pressurizing element 44 includes three plungers, with each
plunger received within a corresponding one of the first pressure
chambers. The plungers create a relatively high non-precision
pressure in the first pressure chambers. Lower, controlled
pressures are built in the secondary chambers by opening the first
valves 70, 84 and 94, which produce a controllable leak into the
secondary chambers. If too much pressure builds up in the secondary
pressure chambers, the corresponding vent valves 76, 86 and 96 are
opened to relieve the pressure.
[0074] When closing the cover 18, the normally open first valves
74, 84 and 94 are closed while the vent valves 76, 86 and 96 are
open. When a predetermined pressure P is achieved in the first
pressure chambers, the vent valves 76, 86 and 96 are closed, and
the first valves 74, 84 and 94 are opened to build a lower pressure
P' in the secondary pressure chambers. The controlled pressure in
the secondary pressure chambers provide the necessary pressures to
the fluidic circuit of the removable cartridge 14 to produce fluid
flow for the blood, lyse and sheath. The velocity of the fluid flow
is then measured by the downstream flow sensors 80, 100 and 102.
Each flow sensor provides an output signal that is used by the
controller or processor 40 to control the operation of the
corresponding first valve and vent valve to provide a desired and
constant flow rate for each fluid.
[0075] Downstream valves generally shown at 110 may also be
provided. Controller or processor 40 may close downstream valves
110 until the system is pressurized. This may help prevent the
blood, lyse and sheath from flowing into the fluid circuit before
the circuit is pressurized. In another illustrative example of the
invention, downstream valves 110 are opened by mechanical action
when the cover is closed.
[0076] FIG. 5 is a schematic diagram showing an illustrative manual
fluid driver having a bulb 100 and check valve 102. The check valve
102 is preferably a one way valve that allows air in but not out of
the first pressure chamber 104. When the bulb 100 is depressed, the
air in the interior 106 of the bulb 100 is forced through the check
valve 102 and into the first pressure chamber 104. Preferably,
another one-way vent valve 105 is provided that allows air in from
the atmosphere but not out of the interior 106 of the bulb 100.
Thus, when the bulb is released, the one-way vent valve 105 may
allow replacement air to flow into bulb 100.
[0077] Rather than using a manually operated fluid driver, it is
contemplated that any relatively small pressure source may be used
including, for example, an electrostatically actuated mesopump. One
such mesopump is described in, for example, U.S. Pat. No. 5,836,750
to Cabuz, which is incorporated herein by reference.
[0078] FIG. 6 is a graph showing proportional pressure control
produced by an 8.times.7 addressable array of microvalves. To
create the graph shown in FIG. 6, 6.5 psi was applied to a first
pressure chamber 120. A small opening was provided to a second
pressure chamber 122. The microvalves are shown at 124, and vent
the pressure in the second pressure chamber 122. By changing the
number of addressable microvalves that are closed, the pressure in
the second pressure chamber can be changed and controlled. In the
graph shown, the pressure in the second pressure chamber 122 could
be changed from about 0.6 psi, when zero of the 8.times.7 array of
microvalves close, to about 6.5 psi, when all of the 8.times.7
array of microvalves are closed. These low power, micromachined
silicon microvalves can be used for controlling pressures up to 10
psi and beyond.
[0079] FIG. 7 is a schematic diagram showing the formation of a
flow stream and core by a flow mechanism block 88, which may
provide hydrodynamic focusing, of FIG. 3. The block 88 may receive
blood, lyse and sheath at controlled velocities from the fluid
driver. The blood may be mixed with the lyse, causing the red blood
cells to be removed. The lysing solution may have a pH lower than
that of the red blood cells. This is often referred to as red cell
lysing or lyse-on-the-fly. The remaining white blood cells are
provided down a central lumen 150, which is surrounded by sheath
fluid to produce a flow stream 50. The flow stream 50 includes a
core stream 160 surrounded by the sheath fluid 152. The dimensions
of the channel are reduced as shown so that the white blood cells
154 and 156 are in single file. The velocity of the sheath fluid is
preferably about 9 times that of the core stream 160. However, the
velocity of the sheath fluid and core stream 160 remain
sufficiently low to maintain laminar flow in the flow channel.
[0080] Light emitters 22a and 22b, and associated optics are
preferably provided adjacent one side of the flow stream 50. Light
detectors 24a and 24b, and associated optics are provided on
another side of the flow stream 50 for receiving the light from the
light emitters 22a and light from fluorescing particles via the
flow stream 50. The output signals from the light detectors 24a and
24b are provided to controller or processor 40, wherein they are
analyzed to identify and/or count selected white blood cells in the
core stream 160.
[0081] FIG. 8 is a schematic diagram showing an array 22a of light
sources and an array 24b of light detectors for analysis of the
core stream 160 via scattering of FIG. 7. The light sources are
shown as "+" signs and the detectors are shown at boxes. In the
example shown, the array of light sources is provided adjacent one
side of the flow stream 50, and the array of light detectors is
provided adjacent the opposite side of the flow stream. Each of the
light detectors is preferably aligned with a corresponding one of
the light sources. The array of light sources and the array of
light detectors are shown arranged along a light source axis 200
that is slightly rotated relative to the axis 202 of the flow
stream 50.
[0082] The array 22a of light sources is preferably an array of
lasers such as vertical cavity surface emitting lasers (VCSELs)
fabricated on a common substrate. Because of their vertical
emission, VCSELs are ideally suited for packaging in compact
instruments such as a miniaturized portable cytometer. Such
cytometer may be wearable on a person's body. Preferably, the
VCSELs are "red" VCSELs that operate at wavelengths that are less
than the conventional 850 nm, and more preferably in the 670 nm to
780 nm range. Red VCSELs may have a wavelength, power and
polarization characteristic that is ideally suited for scatter
measurements.
[0083] Some prior art cytometer bench models use a single 9 mW
edge-emitting laser with a wavelength of 650 nm. The beam is
focussed to a 10.times.100 micron elongated shape to cover the
uncertainty in particle position due to misalignment and width of
the core stream. In contrast, the output power of the red VCSELs of
the present invention, operating at 670 nm, is typically around 1
mW for a 10.times.10 micron emitter and 100-micron spacing. Thus,
the total intensity of the light from a linear array of ten red
VCSELs may be essentially the same as that of some prior art bench
models.
[0084] Using a linear array of lasers oriented at an angle with
respect to the flow axis 202 offers a number of important
advantages over the single light source configuration of the prior
art. For example, a linear array of lasers may be used to
determining the lateral alignment of the path of the particles in
the core steam. One source of uncertainty in the alignment of the
particle stream is the width of the core flow, which leads to
statistical fluctuations in the particle path position. These
fluctuations can be determined from analysis of the detector data
and can be used by the controller or processor 40 to adjust the
valves of the fluid driver in order to change the relative
pressures that are applied to the sample fluid and the supporting
fluids to change the alignment of the selected particles in the
flow stream.
[0085] To determine the lateral alignment of the cells in the fluid
stream 50, the cells pass through several focussed spots produced
by the linear array of VCSELs. The cells produce a drop in signal
in the corresponding in-line reference detectors. The relative
strengths of the signals are used by the controller or processor 40
to determine the center of the particle path and a measure of the
particle width.
[0086] For determining particle path and size, the lasers 22a are
preferably focussed to a series of Gaussian spots 214 (intensity on
the order of 1000 W/cm.sup.2) in the plane of the core flow. The
spots 214 are preferably about the same size as a white blood cell
(10-12 um). Illustrative Gaussian spots 214 are shown in FIG. 9.
Arrays 24a of detectors and their focusing optics are provided on
the opposite side of the fluid stream 50. Lenses with fairly large
F-numbers are used to provide a working space of several hundred
microns for the cytometer section of the removable cartridge.
[0087] Another advantage of using a linear array 22a of lasers
rather than a single laser configuration is that the velocity of
each cell may be determined. Particle velocity can be an important
parameter in estimating the particle size from light scatter
signals. In conventional cytometry, the particle velocity is
extrapolated from the pump flow rates. A limitation of this
approach is that the pumps must be very precise, the tolerance of
the cytometer flow chambers must be tightly controlled, no fluid
failures such as leaks can occur, and no obstructions such as
microbubbles can be introduced to disturb the flow or core
formation.
[0088] To determine the velocity of each cell, the system may
measure the time required for each cell to pass between two
adjacent or successive spots. For example, and with reference to
FIG. 8, a cell may pass detector 208 and then detector 210. By
measuring the time required for the cell to travel from detector
208 to detector 210, and by knowing the distance from detector 208
to detector 210, the controller or processor 40 can calculate the
velocity of the cell. This would be an approximate velocity
measurement. This is often referred to as a time-of-flight
measurement. Once the velocity is known, the time of travel through
the spot on which the particle is centered (a few microseconds) may
provide a measure of particle length and size.
[0089] It is contemplated that the particle velocity can also be
used to help control the fluid driver. To reduce the size, cost and
complexity of the present invention, the replaceable cartridge of
FIG. 1 may be manufactured from a plastic laminate or molded parts.
While such manufacturing techniques may provide inexpensive parts,
they are typically less dimensionally precise and repeatable, with
asymmetrical dimensions and wider tolerance cross-sections. These
wider tolerances may produce variations in particle velocity,
particularly from cartridge to cartridge. To help compensate for
these wider tolerances, the time-of-flight measurement discussed
above can be used by the controller or processor 40 to adjust the
controlled pressures applied to the blood, lyse and sheath fluid
streams such that the particles in the core stream have a
relatively constant velocity.
[0090] To further evaluate the cell size, it is contemplated that
laser beams may be focused both along the cell path and across the
cell path. Additionally, multiple samples across the cell may be
analyzed for texture features, to correlate morphological features
to other cell types. This may provide multiple parameters about
cell size that may help separate cell types from one another.
[0091] Another advantage of using a linear array 22a of lasers
rather than a single layer configuration is that a relatively
constant light illumination may be provided across the flow
channel. This is accomplished by overlapping the Gaussian beams 214
from adjacent VCSELs 22a, as shown in FIG. 9. In prior art single
laser systems, the light illumination across the flow channel
typically varies across the channel. Thus, if a particle is not in
the center of the flow channel, the accuracy of subsequent
measurements may be diminished.
[0092] To perform the above described measurements, each detector
24a in FIG. 8 may be a single in-line detector. To measure FALS and
SALS scatter, however, each detector 24a may further include two
annular detectors disposed around the in-line detector, as shown in
FIG. 10. Referring to FIG. 10, a VCSEL 218 is shown providing light
in an upward direction. The light is provided through a lens 220,
which focuses the light to a Gaussian spot in the plane of the core
flow. Lens 220 may be a microlens or the like, which is either
separate from or integrated with the VCSEL 218. The light passes
through the core flow, and is received by another lens 222, such as
a diffractive optical element. Lens 222 provides the light to
in-line detector 226 and annular detectors 228 and 230. The in-line
detector 226 detects the light that is not significantly scattered
by the particles in the core stream. Annular detector 228 detects
the forward scatter (FALS) light, and annular detector 230 detects
the small angle scatter (SALS) light.
[0093] FIG. 11 shows another illustrative example of the present
invention that includes three separate arrays of light sources and
light detectors. Each array of light sources and light detectors
are positioned along a different light source axis that is slightly
rotated relative to the central flow axis of the flow stream. By
using three arrays, the optics associated with each array may be
optimized for a particular application or function. For detecting
small angle scattering (SALS), laser light that is well-focussed on
the plane of the core flow is desirable. For detecting forward
scattering (FALS), collimated light is desirable.
[0094] Referring specifically to FIG. 11, a first array of light
sources and light detectors is shown at 300. The light sources and
light detectors are arranged in a linear array along a first light
source axis. The first light source axis is rotated relative to the
flow axis of the flow stream. The light sources and light detectors
may be similar to that described above with respect to FIG. 8, and
preferably are used to measure, for example, the lateral alignment
of the cells in the flow stream, the particle size, and the
velocity of the particles.
[0095] FIG. 11a is a three dimensional illustration of an array of
light sources 351 and an array of light detectors 353 positioned
along a light source axis 355 and detector axis 357, respectively,
which are not parallel (i.e., are statically rotated) relative to
the central flow axis of the flow stream 359. Axes 355, 357 and 361
are typically parallel to one another. Line 361 is an axis of light
spots across flow stream 359.
[0096] FIG. 12 is a schematic diagram showing an illustrative light
source and detector pair of the first array 300 shown in FIG. 11. A
VCSEL 302 is shown providing light in an upward direction. The
light is provided through a lens 304, which focuses the light to a
Gaussian spot in the plane of the core flow. The light passes
through the core flow, and is received by another lens 306. Lens
306 provides the light to in-line detector 308. The in-line
detector 308 detects the light that is not significantly scattered
by the particles in the core stream.
[0097] A second array of light sources and light detectors is shown
at 310. The light sources are arranged in a linear array along a
second light source axis that is rotated relative to the flow axis
of the flow stream. The light detectors include three linear arrays
of light detectors. One array of light detectors is positioned in
line with the linear array of light sources. The other two linear
arrays of light detectors are placed on either side of the in-line
array of light detectors, and are used for measuring the small
angle scattering (SALS) produced by selected particles in the flow
stream.
[0098] FIG. 13 is a schematic diagram showing an illustrative light
source and corresponding detectors of the second array shown in
FIG. 11. A VCSEL 320 is shown providing light in an upward
direction. The light is provided through a lens 322, which focuses
the light to a Gaussian spot in the plane of the core flow. The
light passes through the core flow, and is received by another lens
324, such as a diffractive optical element (DOE) 324. Lens 324
provides the light to the in-line detector 326 and the two
corresponding light detectors 328 and 330 placed on either side of
the in-line light detector 326.
[0099] The in-line detector 326 may be used to detect the light
that is not significantly scattered by the particles in the core
stream. Thus, the in-line linear array of light detectors of the
second array 302 may be used to provide the same measurements as
the in-line array of detectors of the first array 300. The
measurements of both in-line arrays of detectors may be compared or
combined to provide a more accurate result. Alternatively, or in
addition, the in-line detectors of the second array 302 may be used
as a redundant set of detectors to improve the reliability of the
cytometer.
[0100] It is contemplated that the in-line detectors of the second
array 302 may also be used in conjunction with the in-line
detectors of the first array 300 to more accurately determine the
time-of-flight or velocity of the particles in the flow stream. The
measurement may be more accurate because the distance between
detectors may be greater. As indicated above, by knowing the
velocity of the particles, small variations in the flow rate caused
by the fluid driver can be minimized or removed by the
controller.
[0101] Light detectors 328 and 330 of FIG. 13 are used to measure
the small angle scattering (SALS) produced by selected particles in
the flow stream. The light detectors 328 and 330 are therefore
preferably spaced sufficiently from the in-line detector 326 to
intercept the small angle scattering (SALS) produced by selected
particles in the flow stream.
[0102] Referring back to FIG. 11, a third array of light sources
and light detectors 350 is preferably provided to measure the
forward angle scattering (FALS) produced by selected particles in
the flow stream. The light sources are arranged in a linear array
along a third light source axis that is rotated relative to the
flow axis of the flow stream. Each light source preferably has a
corresponding light detector, and each light detector is preferably
annular shaped with a non-sensitive region or a separate in-line
detector in the middle. The annular shaped light detectors are
preferably sized to intercept and detect the forward angle
scattering (FALS) produced by selected particles in the flow
stream.
[0103] FIG. 14 is a schematic diagram showing an illustrative light
source and detector pair of the third array of light sources and
light detectors 350 shown in FIG. 11. A VCSEL 360 is shown
providing light in an upward direction. The light is provided
through a lens 362 such as a collimating lens, which provides
substantially collimated light to the core flow. As indicated
above, collimated light is desirable for detecting forward
scattering (FALS) light. The light passes through the core flow,
and is received by another lens 364. Lens 364 provides the received
light to the annular shaped detector 368.
[0104] The annular shaped detector 368 is preferably sized to
intercept and detect the forward angle scattering (FALS) produced
by selected particles in the flow stream. A non-sensitive region or
a separate in-line detector 370 may be provided in the middle of
the annular shaped detector 368. If a separate in-line detector 370
is provided, it can be used to provide the same measurement as the
in-line detectors of the first array 300 and/or second array 302.
When so provided, the measurements from all three in-line arrays of
detectors of first array 300, second array 302 and third array 350
may be compared or combined to provide an even more accurate
result. The in-line detectors of the third array 302 may also be
used as another level or redundancy to improve the reliability of
the cytometer.
[0105] It is contemplated that the in-line detectors of the third
array 350 may also be used in conjunction with the in-line
detectors if the first array 300 and/or second array 302 to more
accurately determine the time-of-flight or velocity of the
particles in the flow stream. The measurement may be more accurate
because the distance between detectors may be greater. As indicated
above, by knowing the velocity of the particles, small variations
in the flow rate caused by the fluid driver can be minimized or
removed by the controller.
[0106] By using three separate arrays of light sources and
detectors, the optics associated with each array can be optimized
for the desired application. As can be seen, the optics associated
with the first array 300 are designed to provide well-focussed
laser light on the plane of the core flow. This helps provide
resolution to the alignment, size and particle velocity
measurements performed by the first array 300. Likewise, the optics
associated with the second array 302 are designed to provide
well-focussed laser light on the plane of the core flow. Well
focussed light is desirable when measuring the small angle
scattering (SALS) produced by selected particles in the flow
stream. Finally, the optics associated with the third array 350 are
designed to provide collimated light to the core flow. As indicated
above, collimated light is desirable when measuring forward angle
scattering (FALS) produced by selected particles in the flow
stream.
[0107] FIG. 15 is a perspective view of an illustrative example of
the miniaturized portable cytometer of the present invention
adapted to be worn around the wrist. This cytometer 400 may be
similar to that shown in FIG. 1. A band 402 secures cytometer 400
to the wrist of a user.
[0108] As indicated above, the user may obtain a removable
cartridge and provide a blood sample to the sample collector port
32 (see FIG. 1) of the removable cartridge. The blood sample may be
collected by, for example, a finger prick. The user may then insert
the removable cartridge into the housing, and manually pressurize
the system. The miniaturized portable cytometer may then provide a
reading that indicates if the user should seek medical treatment.
The reading may be a visual reading, an audible sound or any other
suitable indicator.
[0109] Rather than obtaining the blood sample by a finger prick or
the like, it is contemplated that a catheter 404 or the like may be
inserted into a vein of the user and attached to the sample
collector port 32. This may allow the system to automatically
collect a blood sample from the user whenever a reading is desired.
Alternatively, it is contemplated that the miniaturized portable
cytometer may be implanted in the user, with the sample collector
port 32 connected to a suitable blood supply.
[0110] FIG. 16 reveals a disposable cytometer cartridge 14
containing the pumps, pressure chambers, reservoirs, flow sensors,
and a flow mechanism with a flow channel. The flow mechanism may
perform hydrodynamic focusing. There might be no external fluid
connections on the cartridge. There may be external electrical
connections from the cartridge 14 to a controller, computer or
processor 40 (hereafter referred to as a processor). However,
processor 40 or a portion of it may be included in the cartridge
14. Processor 40 or a portion of it may be in a form of a chip.
External to cartridge 14 may be a light source or sources and
detector or detectors associated with the flow channel on the
cartridge 14. All of the liquids are self-contained in the
cartridge except for a blood sample that is to be analyzed which is
input directly to the cartridge via a port 32.
[0111] A pump 81 may pump air into a pressure chamber 70. Pump 81
may be a mesopump as described as an illustrative example by U.S.
Pat. No. 5,836,750. Pump 81 may be controlled by processor 40 via a
line 89 and connection block 87. The air may enter a controlled
pressure chamber 72 via a valve 74. The air in chamber 72 may be
controlled to be at some pre-determined pressure with mesovalves or
other microvalves 74 and 76. The air may proceed into blood
reservoir 62. Valve 74 may open and valve 76 may close when more
air pressure is needed in chamber 72. Valve 74 may close and valve
76 may open if there is a need to reduce the air pressure in
chamber 72. Valves 74 and 76 may be controlled by processor 40 via
line 91 and connection block 60. Block 60 represents appropriate
connections from line 91 to the valves of chamber 72. The air may
proceed through a porous filter 61 on to a blood reservoir 62.
Filter 61 may permit a passage of air but blocks the passage of
liquid. The air may exert a controlled pressure on the liquid blood
in the reservoir 62. The blood may flow from the reservoir 62
through flow sensor 80. Flow sensor 80 may provide information
relating to the amount of blood flowing through the sensor via a
connection block 48 and line 93 to processor 40. With the sensed
blood flow information, processor 40 may send control signals to
valves 74 and 76 to control the air pressure upon the liquid in the
reservoir 62 so as to result in a predetermined flow rate of the
blood into a flow mechanism 88 which may have a flow channel and
hydrodynamic focusing.
[0112] In a similar fashion as for the blood provision, the lyse
provision may have a pump 83 that pumps air into a pressure chamber
71. Pump 83 may be like pump 81. Pump 83 may be controlled by
processor 40 via the line 89 and connection block 87. The air may
enter a controlled pressure chamber 75. The air in chamber 75 may
be controlled to be at some predetermined pressure with valves 84
and 86. The air may proceed on through a porous filter 63 to a lyse
reservoir 64. Valve 84 may open and valve 86 may close when more
air pressure is needed in chamber 75. Valve 84 may close and valve
86 may open if there is a need to reduce air pressure in chamber
75. Valves 84 and 86 may be controlled by processor 40 via line 91
and connection block 60. Block 60 represents an appropriate
connection from line 91 to the valves of chamber 75. The air may
proceed through a porous filter 63 on to a lyse reservoir 64.
Filter 63 may permit a passage of air but block the passage of
liquid. The air may exert a controlled pressure on the liquid lyse
in the reservoir 64. The lyse may flow from the reservoir through
flow sensor 100. Flow sensor 100 may provide information about the
amount of lyse flowing through the sensor via a connecting block 48
and line 93 to processor 40. With the sensed lyse flow information,
processor 40 may send control signals to valves 84 and 86 to
control the air pressure upon the liquid in the reservoir 64 so as
to result in a predetermined flow rate of the lyse into a flow
focusing mechanism 88.
[0113] In a similar fashion, as for the blood and lyse provisions,
the sheath provision may have a pump 85 that pumps air into a
pressure chamber 73. Pump 85 may be a pump like pumps 81 and 83.
Pump 85 may be controlled by processor 40 via the line 89 and
connection block 87. The air may enter from chamber 73 to a
controlled pressure chamber 77. The air in chamber 77 may be
controlled to be at some predetermined pressure with valves 94 and
96. The air may proceed from chamber 77 through a porous filter 65
on to a sheath reservoir 66. Valve 94 may open and valve 96 may
close when more air pressure is needed in chamber 77. Valve 94 may
close and valve 96 may open if there is a need to reduce air
pressure in chamber 77. Valves 94 and 96 may be controlled by
processor 40 via line 91 and connection block 60. Block 60
represents an appropriate connection from line 91 to the valves of
chamber 77. The air may exert a controlled pressure on the liquid
sheath in the reservoir 66. The sheath may flow from the reservoir
through flow sensor 102. Flow sensor 102 may provide information
about the amount of sheath flowing through the sensor 102 via a
connecting block 48 and line 93 to processor 40. With the sensed
sheath flow information, processor may send signals to pump 85 and
valves 94 and 96 to control the air pressure upon the sheath liquid
in the reservoir 66 so as to result in a predetermined flow rate of
the sheath into the flow mechanism 88. Ports, connected to an
external pressurized air supply, may be implemented in lieu of
pumps 81, 83 and 85 on cartridge 14 in FIG. 16.
[0114] In the flow mechanism 88, the blood from reservoir 62 may be
lysed of its red blood cells and inserted with a flow channel (50)
with a sheath liquid around the stream of the white cells
(remaining) in the blood into a single file. The white cells and
other particles may be illuminated by light sources, and light from
the flow channel may be detected by detectors. The light sources
and detectors may be controlled and information may be had from
them via connections on line 97 between processor 40 and mechanism
88. Mechanism 88 and the flow channel are described in other places
of the present description. After the blood sample along with the
sheath leave the flow channel of mechanism, it may go into the
waste reservoir 52.
[0115] Before the cartridge 14 is used and until its system is
pressurized, a set of downstream valves 110 between reservoirs 62,
64 and 66 and mechanism 88 may be closed. Their closure and open
status may be controlled by processor 40 via line 95 and connection
block 110.
[0116] FIG. 17a is another version of the cartridge 14 where all of
the liquid devices and operations occur on cartridge. FIG. 17b
reveals the same version as that of FIG. 17a except a portion or
all of the processor 40 may be situated in the cartridge 14.
Processor 40 in FIG. 17b may communicate externally from the
cartridge 14 via line 155. The cartridge 14 in FIGS. 17a and 17b
may have a set of valves that are closed to seal off the fluids in
the reservoirs 64 and 66 while cartridge 14 is on the shelf. The
valves may be mesovalves. Processor 40 may control valves via a
line 113 and a connection block 111 providing a connection from the
valves to line 113. Also, the input 32 may be closed off from blood
reservoir 62 with a valve 109. Valve 109 may be a mesovalve or
other microvalve connected to processor 40. While cartridge 14 is
on the shelf, downstream valves between the flow sensors and
mechanism 88 may be closed. Also, before cartridge 14 is used and
until its system is pressurized, the downstream valves may be
closed. The closure and open status of the downstream valves may be
controlled by processor 40 via line 95 and connection block 110.
Porous filters 61, 63 and 65 to reservoirs 62, 64 and 65,
respectively, may prevent the passage of liquid but permit the
passage of air, assuming the valves of block 111 are open, to enter
the reservoirs 62, 64 and 66, so that when the liquids are pumped
out the respective reservoirs, the removed liquids may be replaced
by air so that a vacuum in not developed in the reservoirs.
[0117] A blood sample may be entered into the blood reservoir 62
via port 32. A pump 81 may pump blood from reservoir 62 through a
flow sensor 80 into the flow mechanism 88. Flow sensor 80 provides
a signal indicating a rate of flow of the blood via connection
block 48 and line 93 to processor 40. Processor 40 may control the
amount of flow through sensor 80 by a control signal to pump 81 via
line 89 and connection block 87.
[0118] Lysing liquid in the lyse reservoir 64 may be pumped through
flow sensor 100 by a pump 83. Flow sensor 100 may sent a signal to
processor 40, indicating a rate of flow of the lyse through the
sensor into the flow mechanism 88. This signal may go to processor
40 via the connection block 48 and line 93. Processor 40 may adjust
the rate of flow of the lyse through sensor 100 with a signal sent
to pump 83 via line 89 and connection block 87.
[0119] Sheath fluid may be pumped by pump 85 from the sheath
reservoir 66 through a flow sensor 102 on into the flow mechanism
88. Flow sensor 102 may send a signal indicating the amount of flow
of the sheath liquid passing through the sensor 102. This signal
may go to processor 40 via the connection block 48 and line 93.
Processor 40 may adjust the amount or rate of flow of the sheath
liquid through sensor 102 and into mechanism 88 with a signal sent
to pump 85 via the line 89 and connection block 87.
[0120] The sample blood may enter mechanism 88 and be lysed with
the fluid pumped from reservoir 64 through sensor 100 to remove the
red blood cells. The lysed blood may go through a flow channel (50)
with a sheath liquid around the blood causing the white cells in
the blood to go through the flow channel in single file. The white
cells and other particles may be illuminated with light from the
light sources. Light from the flow channel may be detected by
detectors. The light sources may be controlled by processor 40 via
line 97 to mechanism 88. The detectors may provide information
signals to processor 40 via line 97. Flow mechanism 88 and the flow
channel with its optics are described in other places of the
present description. After the blood sample along with the sheath
liquid leave the flow channel of the mechanism, it may go into the
waste reservoir 52.
[0121] FIGS. 18a-18d show a microfluidic cartridge or chip 14 which
may be produced with a rapid prototyping, laser-cutting lamination
technology. A single type of reagent may be used, but for the
convenience of driving, three reagent reservoirs may be included on
the fluidic cartridge or chip 14, together with a waste container
52. Also, on the chip may be a sample-collecting capillary 32. The
reagent reservoirs 62, 64 and 66 may have a pneumatic/hydraulic
interface with the cover of the cytometer, which may ensure fluid
driving inside of the fluidic chip 13. The interface may be either
a flexible diaphragm or a porous plug (the latter is shown) 61, 63
and 65 that may permit air to move through, but prevent fluid loss.
Plugs 61, 63 and 65 may be located at ports 123, 125 and 126,
respectively. As part of a fluid-driving system, flow-sensor dies
80, 100 and 102 may be included on the fluidic chip. The electrical
connection may be achieved through metal lines deposited on the
cartridge 14 and connected to the external holder.
[0122] During storage, a removable cap 114 may be attached to the
microfluidic circuit of chip 14. Lyse may be stored on board in
reservoir 64. Valves 115 and 116 may be open. Valves 117, 118, 119
and 121 may be closed. One may do an analysis or test on cartridge
14.
[0123] Cap 114 may be removed and a drop of blood may put into the
sample inlet 32. Capillary action may draw the blood into the
sample storage sub-circuit. The cap 114 may be snapped on to the
sample inlet 32 and the cartridge 14 may be placed into the
cytometer case or bench apparatus.
[0124] By closing the cover of the chip, card or cartridge 14
holder, valves 115 and 116 may close and valves 117, 118, 119 and
121 may open as in FIG. 18b. Reservoirs 62, 64 and 66 may be driven
by different pressures at ports 123, 125 and 126, respectively, to
produce different flow rates in the corresponding fluid lines.
Whole blood may be pushed into the sample injector 129 by blood
driver/reservoir 62 via valve 121, line 128, valve 117 and line 127
at a flow rate of approximately 0.1 microliter per second. In
parallel, lyse from reservoir 64 may be pushed, via valve 118 and
line 131 of FIG. 18b, on to sample injector 129 at a flow rate of
approximately 1 microliter per second. In FIG. 18c, the lyse and
whole blood may be co-eluded into a mixing and lysing channel 133
to produce a total of about 13 microliters of about 10 to 1 diluted
blood (viz., the sample). The red blood cells are lysed, leaving
white blood cells remaining in the sample. In FIG. 18d, a sheath
fluid may be pushed via valve 119 and line 132 into a focusing
chamber 134 at a rate of about 7 microliters per second. Blood flow
may be stopped with the reduction of the pressure load in reservoir
62 to zero, while the pressure load in reservoir 64 is adjusted to
produce a sample (lysed blood) at a flow rate of about 0.5
microliter per second. The sheath fluid in chamber 134 may cause
the while cells of the blood sample to be hydrodynamically focused
or the like in area 135 into single file core stream to flow
through flow channel 50. These flow rates may be needed for
producing a core stream with dimensions of about 10.times.5 microns
in the cytometer flow channel 50.
[0125] The particles or cells in flow channel 50 may pass by the
light source and detector system 136. Small angle scattering
(SALS), forward angle scattering (FALS) and large angle scattering
(LALS) caused by the particles in the flow stream may be detected.
Arrays of light sources and detectors may be used. Also,
interruptions of direct light may be detected. Particle width,
length, center and velocity may be determined. Various other
properties and identification information of the particles may be
obtained with the optical system.
[0126] A previous cytometer system used so-called volume-controlled
flow, generated by miniature syringe pumps driven with stepper
motors or manually, to drive all reagents and the sample through
the microfluidic circuit of cartridge 14. The system may be precise
but is extremely bulky and uses significant electrical power. In
order to miniaturize and make energy efficient the fluid driving
system, the open-loop, very precise and stable but bulky and
expensive fluid driving elements may be replaced with less precise
and less stable pressure sources which can be adjusted in a closed
loop configuration to maintain a constant, desired flow velocity at
critical points of the fluidic circuit. Implementation of this
approach may rely on small and sensitive fluid flow sensors for
measurement of flow rates as low as 10 nanoliters per second in
sub-millimeter channels, and fast and small actuators for closed
loop, pressure control.
[0127] There may be a manually pressurized system described in
other places of this description. Another approach may involve
active pumping accomplished with mesopump channels. FIGS. 19a and
19b reveal an application of the mesopumps 137 and mesovalves 138
embedded in a chip, card or cartridge 14. There may also be
embedded flow sensors 139 in chip 14. FIGS. 19a and 19b show an
illustrative example of a portion of a fabricated chip or cartridge
14 with the embedded components. FIG. 19b is a top view of the
portion of a cytometer and FIG. 19a is a cut away side view
revealing the structural relationship of the components relative to
the chip 14. Configurations of the cartridges as shown in FIGS. 16,
17a and 17b, as illustrative examples, may have embedded mesopumps
137 as pumps 81, 83 and 85, and mesovalves 138 as the valves in
blocks 110 and 111 of FIGS. 16, 17a and 17b, and mesovalves 138 as
valves 74, 76, 84, 86, 94 and 96 of pressure chambers 72, 75 and 77
of FIG. 16. Other valves in the system may be embedded mesovalves
138. Similarly, valves 115-119 and 121 of the cartridge 14 of FIGS.
18a-18d may be embedded mesovalves 138. Flow sensors 80,100 and 102
of cartridge 14 of FIGS. 16, 17a, 17b, 18a-18d, 19a and 19b may be
embedded flow sensors 139. However, the pumps and valves may be
another kind of small valves and pumps.
[0128] Mesopumps 137 may be, for an example, dual diaphragm pumps
which are in principle described in U.S. Pat. No. 6,179,586 B1,
issued Jan. 30, 2001, which is incorporated herein by reference.
Also, information related to mesopumps and valves may be disclosed
in U.S. Pat. No. 5,836,750, issued Nov. 17, 1998, which is
incorporated herein by reference. U.S. Pat. Nos. 6,179,586 B1 and
5,836,750 are owned by the entity that owns the present
invention.
[0129] FIGS. 20a and 20b reveal an illustrative example of a
mesovalve 141 in a closed state and an open state, respectively. In
FIG. 20a, there may be a diaphragm 142 closing off an output port
149 at the valve-like seat 144 of a lower structure 145. Diaphragm
142 may have a first electrode 146 coated on it. Surfaces of an
inside cavity 151 of a top structure 148 may have a second
electrode 147 coated on them. Lower structure 145 may have an input
port 143 to the mesovalve 141. Diaphragm 142 may seal the output
port 149 from the tension of diaphragm 142 being held between the
upper and lower structures. The valve seat 144 upper surface may be
slightly higher than the surface of the perimeter of the lower
structure 145 securing the diaphragm 142. Also, there may be a
repelling electrostatic force between electrodes 146 and 147
pushing diaphragm 102 against the valve-like seat 144.
[0130] In FIG. 20b, diaphragm 142 may be lifted off of valve-like
seat 144 with an attracting electrostatic force between the
electrode 146 attached to diaphragm 142 and electrode 147 adhered
to the inside surfaces of top structure 148. With diaphragm 142
lifted off of surface or seat 144, a fluid 153 may flow from the
import port 143 in a cavity 153 below diaphragm 142, through the
cavity, and past the seat surface 144 into the output port 149. The
electrostatic force attracting electrodes 146 and 147 may be caused
by an application of an electrical voltage to the electrodes 146
and 147. When the electrical voltage across the electrodes 146 and
147 is removed, electrostatic attraction between diaphragm 142 and
the inside surfaces of top structure 143 disappear, diaphragm 142
may fall and return its original position against surface 144 which
seals off the output port 149 to stop the flow of fluid 153 through
the mesovalve 141.
[0131] FIG. 21 shows a fluid micro or mesovalve 159 situated or
embedded in the cartridge 14, having an off-cartridge controller 40
connected to the valve. Valve 159 may be another kind of valve
situated in the cartridge. FIG. 22 shows the cartridge 14 having a
fluid pump 158 embedded or built into it. Pump 158 may provide
unidirectional or bidirectional flow. The pump may be a mesopump or
other kind of a pump. It may be utilized for gas or liquid. Pump
158 may be open-loop controlled by control 40. Control 40 may be a
processor and/or a controller. The present pumps and valves
discussed in this description may have thicknesses from 0.8 mm to
1.0 mm, which might be reduced. However, the pumps and valves may
be as thin as 0.2 mm. Application of various technologies may
reduce the thicknesses even further. The pumps and valves may have
diameters of about 10 mm. The pumps and valves may be stacked upon
each other whether they are connected to one another or not. The
range of thicknesses of cartridge 14 may be about 1 mm to 5 mm,
i.e., generally a thickness less than 6 mm, but should be less than
10 mm, although it could be thinner than 1 mm. Lateral dimensions
of the cartridge 14 may be less than 5 cm by 7 cm, but should be
less than 10 cm by 15 cm, or an area less than 150 square cm. The
cartridge could be about the size of a typical credit card. In
certain applications, the cartridge may be thicker than 10 mm
and/or larger than 10 cm by 15 cm or an area larger than 150 square
cm. This larger size cartridge may encompass much more complex
microfluidics. The pumps and valves may be encompassed in the
cartridge 14 using laminate technologies. There may be embedded
components such as pumps and valves that are put into the cartridge
or built in as a part of the layers of the cartridge. The cartridge
14 may also have other components including flow sensors, pressure
sensors, passage ways, devices for preventing a flow of liquid,
channels and reservoirs for fluids and their flow. These components
may be micro-components, including mesopumps and mesovalves. The
pumps may be unidirectional or bidirectional. Some of these
components may be situated on the cartridge and some may be
situated off the cartridge 14. The combination of on-cartridge and
off-cartridge components may vary according to application of the
cartridge. Not all combinations of on-cartridge and off-cartridge
components are necessarily shown in the Figures of the present
description. The cartridge 14 may be treated as a disposable or
non-disposable item after usage. When used for blood analysis, the
cartridge 14 would likely be disposed of for sanitary reasons. If
the cartridge is used for water, environmental, pollutant or like
analysis, the cartridge 14 may be reusable.
[0132] The flow of fluid in the configuration of FIG. 22 may be
determined by noting the number of cycles of pump 158 per volume
unit of flow. The flow amount may be set by control 40 of the pump.
FIG. 23 shows a liquid pump 161 on the cartridge 14. Pump 161 may
be unidirectional or bidirectional. A liquid may be pumped by pump
161 in either direction past a liquid flow sensor 163. The sensor
163 may also be embedded or built into cartridge 14. Flow sensor
163 may provide a feedback signal to control 40 to indicate the
amount and direction of flow. Control 40 may maintain a closed loop
control of pump 161 so as to provide a specific flow on cartridge
14. FIG. 24 shows a similar type of fluid circuit as that in FIG.
23, except it shows a gas pump which may be designed to pump a gas
in one or two directions in cartridge 14. The pumps in the various
configurations of this description may be a mesopumps or other
kinds of micropumps. Also, the valves of the configurations may be
mesovalves or other kinds of microvalves. Some of these pumps may
pump both gas and liquid. A gas flow sensor 164 may indicate a
direction and an amount of flow on cartridge 14. A gas flow
indication may be sent to control 40 which in turn provides an
input to pump 162 so as to provide a desired flow.
[0133] FIG. 25 shows another pumping configuration for providing or
removing a liquid from a reservoir 165 on a cartridge 14. The pump
162, open loop controlled by control 40, may provide gas through a
buffer 166 (which may be like a pressure chamber) to apply pressure
to the reservoir 165. Buffer 166 may smooth out the pulsations in
the gas flow caused by gas pump 162. There may be a device or
membrane 157 that may permit gas but not liquid to go through it.
The buffer 166 may not be needed in some configurations. The gas
may go to a liquid reservoir 165 and with a build up of pressure of
the gas on the liquid in the reservoir 165 to push out the liquid
from the reservoir. FIG. 26 shows a similar configuration not on a
cartridge 14. Certain portions of this configuration may be on or
off of the cartridge 14.
[0134] FIG. 27 is similar to FIG. 25 except that the configuration
of the FIG. 27 has a closed loop control with a flow sensor 163.
The gas pump 162 may pump a gas to liquid reservoir 165 via buffer
166. Pump 162 may be unidirectional or bidirectional. Gas to the
reservoir 165 may provide pressure on the fluid to move it from the
reservoir 165 through the liquid flow sensor 163. A device 157 may
prevent liquid from flowing back into buffer 166 but will let gas
go through in either direction. The flow sensor 163 may send a
signal to control 40 indicating an amount of liquid flow from the
reservoir. Control 40 may provide a signal to gas pump 162 to
control the amount of gas pumped so as to maintain an appropriate
gas pressure and/or desired flow of liquid from the reservoir 163,
via the closed loop connections to and from control 40. FIG. 28
reveals a similar configuration of the one in FIG. 27, except that
it may be wholly or partially off of the cartridge 14.
[0135] FIG. 29 reveals another configuration that may be inserted
in cartridge 14. A gas 162 pump may pump a gas through a buffer 166
and onto a pressure chamber 167 at an input having a valve 168.
Also, chamber 167 may have a relief-like valve 169. Valves 168 and
169 may be actuated by control 40 to open or close individually.
The pump 162 may be unidirectional or bidirectional. The gas may
proceed from chamber 167 to the liquid reservoir 165 where a
pressure of the gas on the liquid in reservoir may force the liquid
through the liquid flow sensor 163. Flow sensor 163 may be off of
the cartridge 14 but still coupled to the microfluidic circuit on
the cartridge. Flow sensor 163 may send a signal indicating flow to
control 40. Control 40 may assure that pump 162 is pumping
sufficient gas. However, the amount of liquid flow through flow
sensor 163 may be controlled by an amount of pressure in chamber
167. If more pressure is needed for increased flow through sensor
163, control 40 may open valve 168 and close valve 169. If the
pressure needs to be decreased to reduce liquid flow through sensor
163, then control 40 may close valve 168 and open valve 169. Valves
168 and 169 may be mesovalves embedded or built into the cartridge
14. The closed loop control may be limited to just the flow sensor
and valve operation. Pump 162, in either configuration, may be a
mesopump or other micropump. FIG. 30 shows another configuration on
cartridge 14 having some resemblance to the configuration of FIG.
29; however, the flow sensor 163 may be on the cartridge 14.
[0136] FIG. 31 shows a configuration having a pressure chamber 176
being controlled differently than chamber 167 of FIGS. 29 and 30. A
gas pump 162 may pump gas through a buffer 166 on to a pressure
chamber 171 via a valve 172. The gas under pressure may go to
liquid reservoir 165. The gas on the liquid in the reservoir may
force the liquid out of the reservoir on through the flow sensor
163. A signal indicating liquid flow may be sent from sensor 163 to
control 40. Control 40 may assure that pump 162 is pumping a
sufficient amount of gas. However, the amount of liquid flow
through flow sensor may be controlled by an amount of pressure on
the gas in chamber 167. The amount of pressure may be detected by
pressure sensor 173 in chamber 171, and a signal indicating the
amount of pressure may be sent from sensor 173 to control 40. If
more flow of liquid is to go through flow sensor 163, then valve
172 may be at least partially opened; and if less flow of liquid is
to go through the flow sensor, then valve 172 may be moved into a
more closed position but not necessarily be completely closed. The
opening and closure of valve 172 may be controlled by signals from
control 40. Instead of a relief valve 169 as in FIG. 31, a
restrictor 174 may be placed in the pressure chamber 171 to provide
some leakage or relief of gas from chamber 171. Valve 172 may be a
mesovalve embedded or built into the cartridge 14. Similarly, the
restrictor or orifice 174 may be built into cartridge 14. Pressure
sensor 173 may be embedded of built into cartridge 14. FIG. 32 may
have a similar configuration as that of FIG. 31, except that the
configuration of FIG. 32 is shown as off of the cartridge. Also,
FIG. 33 may have a similar configuration as that of FIG. 30, except
that the latter is shown as off of the cartridge. Certain portions
of either configuration may be on or off the cartridge.
[0137] The configurations of FIGS. 29-33 may have several closed
loop control arrangements which may be implemented separately or in
combination. The flow sensor and gas pump in conjunction with each
other may provide sufficient closed loop control. The pressure
chamber and its valves with a flow sensor may provide sufficient
closed loop control. In FIGS. 31 and 32, the pressure chamber with
the pressure sensor and valve may separately provide sufficient
closed loop control.
[0138] Although the some of the components discussed in FIGS.
21-33, except control 40, may reside on the cartridge 14, some of
the components may be located off of the cartridge. Further,
control 40 may be a chip embedded or built into the cartridge 14,
although control 40 or a portion of it may often be located off of
the cartridge. In FIGS. 27 and 29-31, gas pump 162 and/or buffer
166 may be located off the cartridge 14. They may be connected via
ports and tubing or other plumbing to cartridge 14 when the
cartridge is placed into a holder that facilitates the fluid and
electrical connections and optical interface for cartridge 14. The
cartridges 14, as in FIGS. 21-25, 27 and 29-31, may be shown merely
in part. These cartridges may have additional components relevant
to specific applications.
[0139] Liquid flow sensor 163 may be embedded or built into the
cartridge 14 or it may be removed from the cartridge which may be
disposed of after usage, and reused in another cartridge 14. Liquid
flow sensor 163 may be may be removable from a slot or holder in
one cartridge 14 for reusability in another cartridge with a
similar slot or holder. The same may apply to the gas flow sensor
164. The various off-cartridge components may be connected to the
components on the cartridge 14 via appropriate plumbing.
[0140] Even though the FIGS. 21-33 show one channel for cartridge
14, a cartridge 14 may have two or more channels having similar or
differing configurations. Also, cartridge 14 may have a flow
channel or like mechanism associated with the configurations of
FIGS. 21-33. A flow channel and additional components may be on the
cartridge 14 even for configurations in the Figures revealing some
or all of the components shown in the respective Figures as being
off the cartridge.
[0141] In the present specification, some of the matter may be of a
hypothetical or prophetic nature although stated in another manner
or tense.
[0142] Although the invention has been described with respect to at
least one illustrative example, many variations and modifications
will become apparent to those skilled in the art upon reading the
present specification. It is therefore the intention that the
appended claims be interpreted as broadly as possible in view of
the prior art to include all such variations and modifications.
* * * * *