Thermal transfer methods and structures for microfluidic systems
Processing devices that include one or more process arrays with thermal transfer structures that can be used alone or in conjunction with gravity/rotation to transport fluids within a microfluidic system. The thermal transport function can be accomplished by changing the temperature of one or more chambers to create a vacuum to draw fluids in selected directions within the process array. The methods and apparatus of the present invention may provide the ability to move fluids in a direction that is against the direction of gravity or any centrifugal forces generated by rotating a processing device using the thermal transfer structures. In other words, fluids may be moved against the direction of gravity or towards the axis of rotation using the thermally-activated vacuum.
1. A processing device comprising:
at least one process array formed in a body, wherein the at least one process array comprises:
a first chamber;
a second chamber;
a process conduit extending between the first chamber and the second chamber;
a thermal transfer structure comprising a thermal drive chamber containing resident fluid and a transfer conduit extending between the first chamber and the thermal drive chamber, wherein the transfer conduit enters the first chamber through a transfer port, and wherein the transfer conduit comprises a fluid trap in which a portion of the transfer conduit travels in an upstream direction between the transfer port and the thermal drive chamber; and
a layer coupled to the body that at least partially defines the at least one process array, the layer comprising
a heat transfer structure that defines at least a portion of the thermal drive chamber and is formed of a different material than the remainder of the base layer to transfer thermal energy into and/or out of the thermal drive chamber.
2. A device according to claim 1 , wherein the fluid trap of the transfer conduit reaches at least a midpoint of the first chamber between the first chamber and the thermal drive chamber.
3. A device according to claim 1 , further comprising a valve located between the first chamber and the thermal drive chamber, wherein fluid passage between the first chamber and the thermal drive chamber through the transfer conduit is prevented until the valve is opened.
4. A device according to claim 1 , wherein the thermal transfer structure further comprises a trap chamber located along the transfer conduit between the first chamber and the thermal drive chamber, wherein the trap chamber is located within the fluid trap or between the fluid trap and the thermal drive chamber.
5. A device according to claim 4 , wherein the trap chamber is connected to the transfer conduit along an upstream end of the trap chamber.
6. A device according to claim 1 , wherein the thermal transfer structure comprises two or more thermal drive chambers, wherein all of the two or more thermal drive chambers are located downstream of the fluid trap in the transfer conduit.
7. A device according to claim 6 , further comprising a valve located between the first chamber and each of the thermal drive chambers, wherein fluid passage between the first chamber and each of the thermal drive chambers through the transfer conduit is prevented until the valve located between the first chamber and the thermal drive chamber is opened.
8. A device according to claim 1 , wherein the process conduit connects to the first chamber in a location downstream from the transfer port.
9. A device according to claim 1 , further comprising a valve located between the first chamber and the process conduit, wherein fluid passage from the first chamber to the second chamber through the process conduit is prevented until the valve is opened.
10. A device according to claim 1 , wherein a plurality of the process arrays are located in the body, wherein the process arrays are substantially radially aligned about a center of the body.
11. A device according to claim 1 , wherein the heat transfer structure is formed of a metallic foil.
12. A device according to claim 10 , wherein the heat transfer structure is in the form of a ring.
13. A device according to claim 12 , wherein the plurality of thermal drive chambers is located within the ring.