Micro-regional thermal control for digital microfluidics

A method of thermal cycling a droplet, the method comprising:

• (a) providing a droplet actuator comprising:
• (i) two or more integrated heaters establishing an integrated heater/sensor arrangement, and comprising a first integrated heater and sensor pair, and establishing at least a first thermal zone and a second integrated heater and respective sensor pair establishing a second thermal zone droplet operations gap, wherein the integrated heater sensor/arrangement provides closed-loop thermal control, and wherein the droplet operations gap is optionally substantially oil filled;
• (ii) a thermal cycling path comprising a plurality of droplet operations electrodes comprising a first droplet operations electrode designated as a first detection electrode in the first thermal zone and a second droplet operations electrode in the second thermal zone, wherein the first and second droplet operations electrodes are within 5 mm of each other;
• (iii) a first temperature at the first droplet operations electrode and a second temperature at the second droplet operations electrode, wherein the first and second temperatures differ by at least about 10° C.;
• (iv) two or more integrated sensors, configured to, in part, measure the two or more heaters and/or the first thermal zone and the second thermal zone, and wherein the two or more integrated heaters and the two or more integrated sensors form at least a first heater/sensor arrangement pair and a second heater/sensor arrangement pair corresponding to at least the first thermal zone and the second thermal zone, wherein the two or more heater/sensor arrangement pairs are configured for micro-regional thermal control of at least the first thermal zone and the second thermal zone;
• (b) using the droplet operations electrodes, transporting the droplet in a cycling pattern for multiple cycles along the thermal cycling path between the first droplet operations electrode and the second droplet operations electrode.