MOVING MICRODROPLETS IN A MICROFLUIDIC DEVICE
The present invention relates to a system and method for moving samples, such as fluid, within a microfluidic system using a plurality of gas actuators for applying pressure at different locations within the microfluidic. The system includes a substrate which forms a fluid network through which fluid flows, and a plurality of gas actuators integral with the substrate. One such gas actuator is coupled to the network at a first location for providing gas pressure to move a microfluidic sample within the network. Another gas actuator is coupled to the network at a second location for providing gas pressure to further move at least a portion of the microfluidic sample within the network. A valve is coupled to the microfluidic network so that, when the valve is closed, it substantially isolates the second gas actuator from the first gas actuator.
1 . A method of identifying one or more nucleic acids in a sample in a microfluidic process module of a microfluidic device, the method comprising:
moving the sample from an upstream channel into a zone located in the microfluidic process module of the microfluidic device;
closing a first valve disposed upstream of the zone and a second valve disposed downstream of the zone such that gas and liquid are prevented from exiting the zone;
thermal cycling the sample in the zone; and
identifying the presence of one or more nucleic acids in the sample in the zone.
2 . The method of claim 1 , wherein moving the sample from the upstream channel into the zone comprises actuating a gas actuator.
3 . The method of claim 2 , wherein actuating the gas actuator comprises increasing a gas pressure in the upstream channel relative to a gas pressure in the zone.
4 . The method of claim 2 , wherein actuating the gas actuator comprises decreasing a gas pressure in the zone relative to a gas pressure in the upstream channel.
5 . The method of claim 1 , wherein closing the first valve and the second valve comprises heating a thermally responsive substance in the first valve and the second valve.
6 . The method of claim 1 , wherein thermal cycling the sample in the zone comprises cyclically heating the sample with a computer-controlled heat source in thermal contact with the zone.
7 . The method of claim 1 , wherein thermal cycling the sample in the zone comprises controlling a plurality of resistive heaters in thermal contact with the zone.
8 . The method of claim 1 , wherein identifying the presence of one or more nucleic acids in the sample in the zone comprises introducing light into the zone, the light selected to generate fluorescence indicative of the presence of one or more amplified nucleic acids in the zone.
9 . The method of claim 1 , further comprising optically detecting an amount of one or more amplified nucleic acids in the zone.
10 . The method of claim 1 , further comprising changing at least one of the first valve and the second valve from a closed state to an open state.