Devices and methods for monitoring and controlling temperature in a microfluidic environment
The present invention provides improved methods that allow accurate monitoring and/or control of temperature changes in a microfluidic environment. An advantage of the present invention is that the temperature can be monitored and/or controlled at any location within a microfluidic device, especially where a preparation step, an amplification step and/or a detection step is performed. The invention further provides improved microfluidic devices for practicing the methods disclosed and claimed herein.
1. A method for monitoring temperature in a digital microfluidic chamber, comprising:
a) combining a first portion of temperature sensitive liquid crystals with a liquid drop, wherein the liquid drop comprises an immiscible fluid and a nonionic emulsifier in the digital microfluidic chamber at an initial temperature;
b) changing the temperature within the digital microfluidic chamber from the initial temperature to a first target temperature; and
c) observing a color change of the first portion of temperature sensitive liquid crystals, thereby monitoring the temperature in a digital microfluidic chamber.
2. The method of claim 1 , wherein the liquid crystals are deposited on a surface of particles or beads.
3. The method of claim 1 , wherein the liquid crystals are immobilized at a plurality of different positions along a vertical dimension.
4. The method of claim 1 , wherein the digital microfluidic chamber comprises a printed circuit board (PCB).
5. The method of claim 4 , wherein the PCB comprises a plurality of electrodes configured to transport the liquid crystals by electrowetting.
6. The method of claim 1 , further comprising combining a second portion of temperature sensitive liquid crystals with the liquid drop wherein a second portion of temperature sensitive liquid crystals undergoes a visible transition at a second target temperature.
7. The method of claim 1 , wherein the temperature sensitive liquid crystals are transported by electrowetting from the first target temperature to a second target temperature.
8. The method of claim 1 , wherein the immiscible fluid is oil.
9. The method of claim 1 , wherein a temperature controller is proximal to the digital microfluidic chamber.
10. The method of claim 4 , wherein the PCB is coated with a hydrophobic insulation.
11. The method of claim 1 , wherein the first target temperature is from about 35° C. to about 99° C.
12. The method of claim 1 , wherein, the liquid droplet further comprises a nonionic emulsifier.
13. A method for monitoring temperature in a droplet, comprising:
a) loading a plurality of temperature sensitive liquid crystals onto a PCB to form the droplet;
b) changing the temperature within the droplet to a target temperature; and
c) observing a visible color change of the temperature sensitive liquid crystals at the target temperature, thereby monitoring the temperature in a droplet.
14. The method of claim 13 , wherein changing the temperature within the droplet comprises moving the droplet by electrowetting manipulation from a first thermal zone to a second thermal zone.
15. The method of claim 13 , wherein the temperature sensitive liquid crystals are in an immiscible fluid.
16. The method of claim 13 , wherein, the droplet further comprises a nonionic emulsifier.
17. A method for monitoring temperature in a microfluidic chamber, comprising:
a) loading a plurality of temperature sensitive liquid crystals into a digital microfluidic chamber;
b) changing the temperature within the digital microfluidic chamber; and
c) observing a visible transition of a first portion of the temperature sensitive liquid crystals at a first temperature, thereby monitoring the temperature in a digital microfluidic chamber.
18. The method of claim 17 , wherein the temperature sensitive liquid crystals are in a liquid droplet.
19. The method of claim 18 , wherein, the liquid droplet further comprises polysorbate 20.
20. The method of claim 19 , wherein the liquid droplet comprises a concentration of polysorbate 20 from about 0.05% to about 10% w/v.