MEMS-based calorimeter, fabrication, and use thereof

Patent metadata

Field	Value
Publication number	US-9513240-B2
Application number	US-201313972783-A
Country	US
Kind code	B2
Filing date	Aug 21, 2013
Priority date	Feb 22, 2011
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

MEMS-based calorimeter including two microchambers supported in a thin film substrate is provided. The thin film substrate includes a thermoelectric sensor configured to measure temperature differential between the two microchambers, and also includes a thermally stable and high strength polymeric diaphragm. Methods for fabricating the MEMS-based calorimeter, as well as methods of using the calorimeter to measure thermal properties of materials, such as biomolecules, or thermodynamic properties of chemical reactions or physical interactions, are also provided.

First claim

The invention claimed is:

1. A microdevice for calorimetric measurement, comprising:
a first thermally isolated microchamber comprising a first serpentine structure, and
a second thermally isolated microchamber comprising a second serpentine structure, each of the first and second serpentine structures have a plurality of long serpentine edges and a plurality of short serpentine edges;
a thin film substrate;
wherein the first thermally isolated microchamber and the second thermally isolated microchamber are each supported on the thin film substrate,
wherein the thin film substrate has a first side constituting a floor of the first and second thermally isolated microchambers and a second side opposing the first side, and
wherein the thin film substrate comprises a thermoelectric sensor, the thermoelectric sensor configured as a thin layer thermopile comprising a plurality of adjacent segments of dissimilar materials, each of the adjacent segments joined together at opposite ends forming a plurality of thermocouple junctions, the thermocouple junctions oriented serially along the long serpentine edges of the first and second serpentine structures of the first and second thermally isolated microchambers, the thermocouple junctions disposed under each of the first and second thermally isolated microchambers and configured to measure the temperature differential between the first and second thermally isolated microchambers.

2. The microdevice of claim 1 , wherein a thermoelectric sensitivity per thermocouple is greater than 80 μV/° C.).

3. The microdevice of claim 1 , where the dissimilar thermoelectric materials comprise n-type and p-type bismuth telluride, and n-type and p-type antimony telluride.

4. The microdevice of claim 1 , wherein the dissimilar materials comprise antimony and bismuth.

5. The microdevice of claim 1 , wherein the material of the polymeric diaphragm has a tensile strength of greater than 55 MPa or Young's Modulus greater than 500 MPa.

6. The microdevice of claim 1 , wherein the material for the polymeric diaphragm is selected from polyimide, parylene, polyester, and polytetrafluoroethylene.

7. The microdevice of claim 1 , wherein the thin film substrate further comprises: a first microheater and a first temperature sensor, each aligned under the first thermally isolated microchamber; and a second microheater and a second temperature sensor, each aligned under the second thermally isolated microchamber.

8. The microdevice of claim 7 , wherein the thermocouple junctions of the thermoelectric sensor are located near the center of the long serpentine edges of each of the first and second serpentine structures, and vertically aligned with the first temperature sensor and the second temperature sensor, respectively.

9. The microdevice of claim 7 , wherein the thermopile is located in a different horizontal plane than and insulated from each of the first and second microheaters and the first and second temperature sensors.

10. The microdevice of claim 7 , wherein each of the first microheater, the first temperature sensor, the second microheater, and the second temperature sensor is in a form of a thin layer of deposited metal/alloy or metals/alloys impregnated in the thin film substrate.

11. The microdevice of claim 10 , wherein each of the first and second microheaters are patterned to provide uniform heating in each of the first and second thermally isolated microchambers.

12. The microdevice of claim 1 , wherein each of the first thermally isolated microchamber and the second thermally isolated microchamber is defined by a surrounding wall made from polydimethylsiloxane (PDMS).

13. The microdevice of claim 1 , wherein the thin film substrate includes a top layer contacting each of the first thermally isolated microchamber and the second thermally isolated microchamber, the top layer made from a mixture of PDMS and the material from which the polymeric diaphragm is made.

14. The microdevice of claim 1 , further comprising a silicon wafer substrate contacting the second side of the thin film substrate.

15. The microdevice of claim 14 , wherein the area on the second side of the thin film substrate corresponding to a cross section of each of the first and second thermally isolated microchambers does not contact any other material except air.

16. The microdevice of claim 1 , further including a first introduction channel and a second introduction channel, each configured to provide passive chaotic mixing for a solution flowing through the first or the second introduction channel.

17. The microdevice of claim 16 , wherein each of the first introduction channel and a second introduction channel comprises a portion having a serpentine shape.

18. The microdevice of claim 16 , wherein each of the first introduction channel and a second introduction channel comprises internal ridges configured to create turbulence in the solution flowing through the first or the second introduction channel.

19. The microdevice of claim 1 , further comprising a thermal enclosure enclosing the microdevice.

20. The microdevice of claim 19 , wherein the thermal enclosure comprises two or more metal enclosures.

21. The microdevice of claim 19 , wherein the microdevice is positioned on a metal stage of the thermal enclosure.

22. The microdevice of claim 19 , wherein the thermal enclosure comprises one or more heaters.

23. The microdevice of claim 22 , wherein the one or more heaters comprise Peltier heaters.

24. The microdevice of claim 22 , wherein the thermal enclosure comprises a controller to adjust a voltage applied to the one or more heaters.

25. The microdevice of claim 19 , wherein the thermal enclosure comprises a heat sink.

26. A method of determining a thermal property of an analyte, comprising:
providing a microdevice, comprising:
a first thermally isolated microchamber comprising a first serpentine structure, and
a second thermally isolated microchamber comprising a second serpentine structure, each of the first and second serpentine structures have a plurality of long serpentine edges and a plurality of short serpentine edges;
a thin film substrate;
wherein the first thermally isolated microchamber and the second thermally isolated microchamber are each supported on the thin film substrate,
wherein the thin film substrate has a first side constituting a floor of the first and second thermally isolated microchambers and a second side opposing the first side,
wherein the thin film substrate comprises:
a thermoelectric sensor, the thermoelectric sensor configured as a thin layer thermopile comprising a plurality of adjacent segments of dissimilar materials, each of the adjacent segments joined together at opposite ends forming a plurality of thermocouple junctions, the thermocouple junctions oriented serially along the long serpentine edges of the first and second serpentine structures of the first and second thermally isolated microchambers, the thermocouple junctions disposed under each of the first and second thermally isolated microchambers and configured to measure the temperature differential between the first and second thermally isolated microchambers;
a first microheater and a first temperature sensor, each aligned under the first thermally isolated microchamber; and
a second microheater and a second temperature sensor, each aligned under the second thermally isolated microchamber;

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Assignees

• Univ Columbia

Inventors

• Lin Qiao
• Wang Bin

Classifications

• G01N25/4893 Primary

  by using a differential method · CPC title

• G01N25/48 Primary

  on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation · CPC title