Systems and methods for thermal actuation of microfluidic devices
A microfluidic processing device includes a substrate defining a microfluidic network. The substrate is in thermal communication with a plurality of N independently controllable components and a plurality of input output contacts for connecting the substrate to an external controller. Each component has at least two terminals. Each terminal is in electrical communication with at least one contact. The number of contacts required to independently control the N components is substantially less than the total number of terminals. Upon actuation, the components typically heat a portion of the microfluidic network and/or sense a temperature thereof.
1. A method of using a microfluidic system, comprising:
providing a first device comprising a first substrate defining a microfluidic network comprising at least one of each of a thermally actuated valve and a thermally actuated reaction chamber;
operatively receiving the first device in a second device, the second device comprising a second substrate defining a plurality of heat sources, each heat source being in thermal communication with a respective one of the thermally actuated valve and the thermally actuated reaction chamber of the first device, wherein at least one of the heat sources is a combined heating and temperature sensing element; and
controlling each heat source of the plurality of heat sources independently.
2. The method of claim 1 , further comprising heating a respective one of the thermally actuated valve and the thermally actuated reaction chamber with the combined heating and temperature sensing element.
3. The method of claim 1 , further comprising sensing a temperature of a respective one of the thermally actuated valve and the thermally actuated reaction chamber with the combined heating and temperature sensing element.
4. The method of claim 1 , further comprising controlling the at least one of each of the thermally actuated valve and the thermally actuated reaction chamber independently of others.
5. The method of claim 1 , further comprising heating only a localized region of the microfluidic network so that the heat generated is sufficient to actuate only a single element of the microfluidic network.
6. The method of claim 1 , wherein the second device has a substantially lower thermal conductivity than the plurality of heat sources.
7. The method of claim 1 , further comprising controlling the heat sources with control circuitry.
8. The method of claim 1 , further comprising receiving signals in the second substrate from a data acquisition and control board.
9. The method of claim 1 , wherein the combined heating and temperature sensing element comprises a resistive temperature sensor.
10. The method of claim 1 , further comprising thermopneumatically actuating the thermally actuated valve.
11. The method of claim 1 , further comprising thermal cycling the reaction chamber to perform a polymerase chain reaction.
12. The method of claim 1 , wherein the thermally actuated valve comprises a temperature responsive substance.
13. The method of claim 12 , wherein the temperature responsive substance is wax.
14. A method of using a microfluidic system, comprising:
providing a first device comprising a first substrate defining a microfluidic network comprising at least one of each of a thermally actuated valve and a thermally actuated reaction chamber;
operatively receiving the first device in a second device, the second device comprising a second substrate defining a plurality of heat sources, each heat source being in thermal communication with a respective one of the thermally actuated valve and the thermally actuated reaction chamber of the first device, wherein at least one of the heat sources is a combined heating and temperature sensing element; and
heating a thermally responsive substance and moving the thermally responsive substance into a channel of the microfluidic network.
15. The method of claim 14 , wherein the temperature responsive substance is wax.
16. The method of claim 14 , further comprising thermal cycling the reaction chamber to perform a polymerase chain reaction.
17. A method of using a microfluidic system, comprising:
providing a first device comprising a first substrate defining a microfluidic network comprising at least one of each of a thermally actuated valve and a thermally actuated reaction chamber;
operatively receiving the first device in a second device, the second device comprising a second substrate defining a plurality of heat sources, each heat source being in thermal communication with a respective one of the thermally actuated valve and the thermally actuated reaction chamber of the first device, wherein at least one of the heat sources is a combined heating and temperature sensing element; and
generating an amount of heat from a first heat source of the plurality of heat sources to actuate a first thermally actuated component but insufficient to actuate a second thermally actuated component.
18. The method of Claim 17 , further comprising controlling the microfluidic system by electrical signals or optical signals received from a data acquisition and control board.
19. The method of claim 17 , further comprising controlling a heat source of the plurality of heat sources independently of another heat source of the plurality of heat sources.
20. The method of claim 17 , further comprising thermal cycling the reaction chamber to perform a polymerase chain reaction.
21. A method of using a microfluidic s stem, comprising:
providing a first device comprising a first substrate defining a microfluidic network comprising at least one of each of a thermally actuated valve and a thermally actuated reaction chamber;
operatively receiving the first device in a second device, the second device comprising a second substrate defining a plurality of heat sources, each heat source being in thermal communication with a respective one of the thermally actuated valve and the thermally actuated reaction chamber of the first device, wherein at least one of the heat sources is a combined heating and temperature sensing element; and
actuating one of the plurality of heat sources such that current flows in essentially only one direction through the heat source.
22. The method of claim 21 , further comprising substantially preventing current flow in a second, opposite direction through the heat source.
23. The method of claim 21 , further comprising controlling the heat sources with control circuitry.
24. The method of claim 21 , further comprising thermal cycling the reaction chamber to perform a polymerase chain reaction.