This invention relates generally to microelectromechanical systems used in biological applications.
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.
Referring to
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.
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.
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.
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.
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.
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.
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.
Thus, in one embodiment, shown in
Referring to
Referring to
Referring to
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.
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
Then, as shown in
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.
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.
This application is a continuation-in-part of U.S. application Ser. No. 11/103,216, filed Apr. 11, 2005.
Number | Date | Country | |
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Parent | 11103216 | Apr 2005 | US |
Child | 11153788 | Jun 2005 | US |