U.S. patent application number 11/153788 was filed with the patent office on 2006-10-12 for controlling biological fluids in microelectromechanical machines.
Invention is credited to Jason T. Cassezza, Terry J. Dishongh, Bradford Needham, Kevin S. Rhodes.
Application Number | 20060227513 11/153788 |
Document ID | / |
Family ID | 37082939 |
Filed Date | 2006-10-12 |
United States Patent
Application |
20060227513 |
Kind Code |
A1 |
Dishongh; Terry J. ; et
al. |
October 12, 2006 |
Controlling biological fluids in microelectromechanical
machines
Abstract
A therapeutic agent may be dispensed into a biological fluid on
an as needed basis. A microelectromechanical system valve may
dispense the therapeutic agent as needed. The valve may sense the
extent of the need for the therapeutic agent and may controllably
open to provide that therapeutic agent in response thereto.
Inventors: |
Dishongh; Terry J.;
(Portland, OR) ; Cassezza; Jason T.; (Beaverton,
OR) ; Rhodes; Kevin S.; (Lynnwood, WA) ;
Needham; Bradford; (North Plains, OR) |
Correspondence
Address: |
TROP PRUNER & HU, PC
1616 S. VOSS ROAD, SUITE 750
HOUSTON
TX
77057-2631
US
|
Family ID: |
37082939 |
Appl. No.: |
11/153788 |
Filed: |
June 15, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11103216 |
Apr 11, 2005 |
|
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11153788 |
Jun 15, 2005 |
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Current U.S.
Class: |
361/718 ;
257/E23.098 |
Current CPC
Class: |
H01L 2924/00 20130101;
F28F 19/002 20130101; H01L 2924/0002 20130101; H01L 2924/0002
20130101; H01L 23/473 20130101; F28F 3/12 20130101; F28F 2255/04
20130101; F28F 27/02 20130101 |
Class at
Publication: |
361/718 |
International
Class: |
H05K 7/20 20060101
H05K007/20 |
Claims
1. A method comprising: providing a microelectromechanical system
valve to sense the need to dispense a therapeutic agent.
2. The method of claim 1 including forming a microelectromechanical
system valve in the form of a leaf valve.
3. The method of claim 2 including forming a depression in a first
substrate and forming said valve over said depression.
4. The method of claim 3 including forming a trench through a
second substrate and securing said first substrate and said second
substrate together.
5. The method of claim 1 including providing fluidic trips to form
turbulent flow proximate to said valve to mix fluid controlled by
said valve.
6. The method of claim 5 including forming said valve with a
bioactive material.
7. The method of claim 6 including forming a bimetal valve.
8. The method of claim 6 including forming a polymer layer on said
valve, said polymer layer including inert particles.
9. The method of claim 8 including functionalizing said inert
particles.
10. The method of claim 9 including arranging said valve to be
actuated in response to a chemical reaction with material on said
inert particles.
11. A dispensing device comprising: a first flow passage; a second
flow passage; and a microelectromechanical system valve to control
the flow of fluid from one passage to the other, said system
including fluidic trips to cause turbulent flow and mixing the
fluids from said first and second flow passages.
12. The device of claim 11 wherein said valve is a leaf valve.
13. The device of claim 12 including a pair of substrates, said
first flow passage formed in one substrate and said second flow
passage formed in the other substrate and said valve formed between
said substrates.
14. The device of claim 11 wherein said valve includes a bioactive
material.
15. The device of claim 11 wherein said valve is a bimetal
valve.
16. The device of claim 15 wherein said valve includes a bioactive
material.
17. The device of claim 14 including a polymer layer and said
bioactive material is embedded in said polymer layer.
18. The device of claim 17 including inert particles embedded in
said polymer layer, said inert particles including a reactive
material coated on said particles.
19. The device of claim 14 wherein said valve is operable in
response to the extent of reactions with said bioactive
material.
20. An apparatus comprising: a pair of passages; a valve to
selectively control the extent of communication between said
passages, said valve including a bioactive material, said valve
operable in response to chemical reactions with said bioactive
material.
21. The apparatus of claim 20 wherein said valve is a leaf
valve.
22. The apparatus of claim 20 wherein said valve is a
microelectromechanical system valve.
23. The apparatus of claim 20 wherein said valve includes a layer
having a coating of bioactive material.
24. The apparatus of claim 23 wherein said layer includes inert
particles having a bioactive coating thereon.
25. The apparatus of claim 24 wherein said inert particles are in
the form of glass beads.
26. The apparatus of claim 25 including a polymer layer and wherein
said glass beads are embedded in said polymer layer.
27. The apparatus of claim 20 wherein reactions with said bioactive
material open said valve when sufficient accumulation occurs on
said valve to pull said valve open.
Description
RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 11/103,216, filed Apr. 11, 2005.
BACKGROUND
[0002] This invention relates generally to microelectromechanical
systems used in biological applications.
[0003] Semiconductor fabricated machines of extremely small
dimensions have potential medical applications. For example,
microelectronic machines may be provided within external apparatus
for the control of patient treatment. In addition, microelectronic
mechanical systems may be sufficiently small that they may be
implanted in situ to provide patient treatment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a greatly enlarged, cross-sectional view in
accordance with one embodiment of the present invention;
[0005] FIG. 2 is a greatly enlarged, cross-sectional view taken
generally along the line 2-2 in FIG. 1 in accordance with one
embodiment of the present invention;
[0006] FIG. 3 is a cross-sectional view corresponding to FIG. 1 in
use in accordance with one embodiment of the present invention;
[0007] FIG. 4 is a cross-sectional view taken generally along the
line 4-4 in FIG. 1 in accordance with one embodiment of the present
invention;
[0008] FIG. 5 is a cross-sectional view taken generally along the
line 5-5 in FIG. 1 in accordance with one embodiment of the present
invention;
[0009] FIG. 6 is an enlarged, cross-sectional view corresponding to
FIG. 1 at an early stage of manufacture in accordance with one
embodiment of the present invention;
[0010] FIG. 7 is an enlarged, cross-sectional view corresponding to
FIG. 6 at a subsequent stage of manufacture in accordance with one
embodiment of the present invention; and
[0011] FIG. 8 is an enlarged, cross-sectional view corresponding to
FIG. 7 at a subsequent stage of manufacture in accordance with one
embodiment of the present invention.
DETAILED DESCRIPTION
[0012] Referring to FIG. 1, an apparatus 10 may be implanted within
a patient or may be external to the patient. Fluid, indicated as A,
may flow in and through the device 10. For example, the flow of
fluid A may be a flow of blood which is to be treated with
appropriate therapeutic agents. The therapeutic agents, indicated
as B, may flow from the passage 14a under control of a
microelectromechanical system (MEMS) leaf valve 16. In other words,
the valve 16 controls the flow of fluid B from the channel 14a into
the channel 14b and thereby regulates the therapeutic
treatment.
[0013] In one embodiment, the apparatus 10 may be made in two
parts, including an upper part 12b and a lower part 12a. The two
parts 12 may be permanently joined along the junction surface 12c
in one embodiment of the present invention. Thus, the part 12b may
have a passage 14a formed therein to allow the passage of the fluid
B while the part 12a may have the passage 14b formed in it. The
parts 12a and 12b may be fabricated using semiconductor fabrication
techniques in some embodiments of the present invention. The
passages 14b and 14a may be formed by conventional lithographic
techniques in one embodiment.
[0014] Controlling the communication between the passages 14a and
14b, a leaf valve 16 includes a first portion 16a secured to the
part 12b and a second portion 16b cantilevered over the passage 14a
in the part 12a. Also formed on the surface 12c and, particularly,
in one embodiment, the outside surface of the part 12b, are a
plurality of roughenings or fluidic trips 18. At least some of the
trips 18 may be located on the surface 12c proximate to the passage
14a.
[0015] The trips 18 function to create turbulent flow at the
interface between the passages 14a and 14b. The turbulent fluidic
flow assists in mixing the two fluids A and B. Thus, the flow of
biological fluid to be treated, indicated at A, may be treated with
the liquid, indicated at B, through a mixing action facilitated by
the trips 18, especially when the valve 16 is opened.
[0016] The valve 16 may be formed of a flexible, multilayer
structure. The lowest layer may include aluminum covered by copper
22. The layers 24 and 22 have different coefficients of thermal
expansion in some embodiments and, therefore, may bend in
controllable ways in response to heating. For example, the makeup
of layers 22 and 24 may be similar to that used in switches for
thermostat control.
[0017] Over the layer 22 may be situated a polymer layer 20 having
formed therein with a coated inert particles such as glass beads
26. Some of the glass beads 26 extend out of the surface of the
layer 20, as indicated at 26a, and others are intermeshed within
the polymer as indicated at 26b. The glass beads 26 may function as
carriers for biological agents. Structures other than glass beads
may also be used.
[0018] The glass beads 26 may be coated with an appropriate
functionalizing material which, in one embodiment, includes
reactive components, such as free radicals, to react with passing
molecules. For example, the glass beads 26 functionalized with a
protein streptavidin may be coated with a layer including
deoxyribonucleic acid (DNA). In other words, the glass beads 26a
may be coated with an appropriate material having free reactive
radicals to react with passing molecules. In one embodiment, this
means that materials in the blood, passing through the passage 14b,
may react and adhere to the exposed glass beads 26a. The glass
beads 26 may be considered bioactive glass beads which are
receptive to bio-agents, such as proteins, which attach to the free
radicals on the glass beads 26a i n one embodiment. "Bioactive"
encompasses any material that may have an effect on any living
tissue.
[0019] As one application, an in vitro delivery of medication may
be made to blood passing through the apparatus 10, passage 14a. A
species within the passing blood may react with the bioactive glass
beads 26a that are exposed on the valve 16. The reactive
constituents adhere to the glass beads 26a and more, particularly,
to a reactive coating on the beads 26c.
[0020] Thus, in one embodiment, shown in FIG. 3, the reactive
constituents in the blood collect on the surface of the valve 16 as
indicated at C. The weight of these constituents pulls the valve 16
open by hingedly rotating the valve portion 16b in a cantilevered
fashion downwardly and away from the passage 14a, still secured at
portion 16a, to the part 12b. As shown in FIG. 3, as a result of
the action of the fluidic trips 18, turbulent flow is generated, as
indicated by the arrows D, facilitating the mixing of the fluid B
in the passage 14a with the fluid A in the passage 14b.
[0021] Referring to FIG. 4, the passage 14a, in one embodiment, may
be a circular portion 14e that includes a connecting portion 14d
which connects to a source of therapeutic agent. Proximate to the
downstream edge of the passage 14a may be the fluidic trips 18. In
some embodiments, the fluidic trips 18 may cover the entire exposed
surface 12c of the portion 12b.
[0022] Referring to FIG. 5, the part 12a may include the passage
14b formed therein. The passage 14b may be a trench aligned with
the circular portion 14e of the passage 14a.
[0023] Referring to FIGS. 6-8, in accordance with one embodiment of
the present invention, the apparatus 10 may be fabricated in an
inverted fashion beginning in FIG. 6. There, a substrate, forming
the part 12b, may have a passage 14a formed therein. The passage
14a may be filled with a material 30 which may be relatively easily
removed, for example, by exposure to heat.
[0024] Over the material 30 and the part 12b may be deposited a
layer that will form the valve 16. The layer that will form the
valve 16 is then patterned and etched to form the portion 16a
adhered to the part 12b and the portion 16b which, at this point,
is still adhered to the material 30 that fills the passage 14a.
[0025] In one embodiment, the trips 18 may be formed as
incompletely removed portions of the layer that forms the valve 16.
In such case, the trips 18, which may be surface roughenings, may
extend across the upper exposed surface 12c of the part 12b at the
stage shown in FIG. 7. In other embodiments, after etching and
defining the valve 16, a coating (not shown) may be applied
thereover which is sufficiently rough to form the trips 18. In
still another embodiment, that coating may be partially removed by
etching, leaving residue which acts as the trips 18.
[0026] Then, as shown in FIG. 8, the material 30 may be removed by
conventional techniques including the application of heat and the
removal by decomposition of the material 30. An example of such a
material is a polymer such as polycarbonate and polynorbornene.
This forms the open passage 14a, better shown in FIG. 4. This
removal also frees the free cantilevered end portion 16b of the
valve 16 to be movable into the passage 14b. Then, the two parts
12b and 12a may be secured together using adhesive or other
techniques. As a result, the passage 14b can receive fluids,
indicated as A, and mix into those fluids, the fluid B in the
passage 14a.
[0027] In some embodiments, the reaction between the treatment
agent and the biological fluid may be controlled on an as needed
basis. In other words, instead of simply flooding the body with
extra treatment agents, such as drugs, that amount of therapeutic
agent may be provided which is actually needed. As a result, the
body is free from being exposed to excessive concentrations of the
treatment agents in some embodiments. In addition, under-treatment
may be reduced as well in some embodiments. Thus, in some
embodiments, just the right amount of therapeutic agents may be
provided.
[0028] While the present invention has been described with respect
to a limited number of embodiments, those skilled in the art will
appreciate numerous modifications and variations therefrom. It is
intended that the appended claims cover all such modifications and
variations as fall within the true spirit and scope of this present
invention.
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