Thermal cycling system
This invention provides a system for performing PCR, and real time PCR in particular with great speed and specificity. The system employs a heat block containing a liquid composition to rapidly transfer heat to and from reaction vessels. The system makes use of the reflective properties of the liquid metal to reflect signal from the PCR into the vessel and out the top. In this way, the signal can be measured by an optical assembly in real time without removing the vessels from the heat block.
1. A thermal cycler apparatus for performing a polymerase chain reaction (PCR) comprising:
a heat block having a top surface and a bottom surface, the heat block comprising:
one or more receptacles located on the top surface and configured to receive one or more sample vessels;
a container containing a liquid composition having a heat transfer coefficient of less than or equal to 5.0 W/m ° K, and wherein the container comprises a closed system with respect to the liquid composition; and
a stir bar in contact with the liquid composition and configured to actively mix the liquid composition;
a heating element in thermal contact with the liquid composition; and
a temperature control assembly in communication with the heating element.
2. The apparatus of claim 1 wherein the liquid composition has a melting temperature of no greater than 50° C.
3. The apparatus of claim 1 , wherein the apparatus is used to perform PCR and the liquid composition expands in volume during PCR by between 0.1% and 6.0%.
4. The apparatus of claim 1 wherein the temperature control assembly comprises resistive wire in thermal contact with the liquid composition.
5. The apparatus of claim 1 wherein the liquid is sealed within the container.
6. The apparatus of claim 1 wherein the apparatus further comprises a reservoir connected to the container.
7. The apparatus of claim 6 wherein the reservoir serves as an overflow to capture any liquid metal or thermally conductive fluid as it expands beyond the volumetric limits of the heat block.
8. The apparatus of claim 6 wherein the reservoir replenishes losses of liquid as they occur during use of the heat block.
9. The apparatus of claim 6 wherein the reservoir is used to maintain or alter the internal pressure in the heat block.
10. The apparatus of claim 1 wherein the heat block comprises more than one stir bar configured to actively mix the liquid composition.
11. The apparatus of claim 1 wherein the stir bar is a horizontal stir bar, a fan shaped stir bar, or a stir bar that has multiple projections.
12. The apparatus of claim 1 wherein the stir bar is magnetically responsive.
13. The apparatus of claim 1 wherein the stir bar is mechanically connected to a motor.
14. The apparatus of claim 1 further comprising an optical assembly wherein the optical assembly comprises a light emitter configured to direct light into a sample vessel and an optical detector configured to detect light emitted from the sample vessel.
15. The apparatus of claim 1 , wherein a top of the bottom surface contacts the liquid composition and a bottom of the bottom surface contacts the heating element.
16. The apparatus of claim 1 , wherein the bottom surface comprises a metal plate.
17. The apparatus of claim 1 , further comprising a lid adapted to cover the top surface of the heat block.
18. The apparatus of claim 17 , wherein the lid comprises a second heating element.
19. The apparatus of claim 1 , wherein the heating element comprises a Peltier heating element.
20. The apparatus of claim 1 , further comprising a heat sink in thermal contact with the heating element.
21. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 4.5 W/m ° K.
22. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 4.0 W/m ° K.
23. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 3.5 W/m ° K.
24. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 3.0 W/m ° K.
25. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 2.5 W/m ° K.
26. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 2.0 W/m ° K.
27. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 1.5 W/m ° K.
28. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 1.0 W/m ° K.
29. The apparatus of claim 1 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 0.5 W/m ° K.
30. The apparatus of claim 1 , wherein the heating element is in contact with the bottom surface of the heat block.
31. A thermal cycler apparatus for performing a polymerase chain reaction (PCR) comprising:
a heat block having a top surface and a bottom surface, the heat block comprising:
one or more receptacles located on the top surface and configured to receive one or more sample vessels; and
a container containing a liquid composition having a heat transfer coefficient of 0.1 to 5 W/m ° K, and wherein the container comprises a closed system with respect to the liquid composition;
a heating element in thermal contact with the liquid composition, wherein the heating element is in contact with the bottom surface of the heat block; and
a temperature control assembly in communication with the heating element.
32. The apparatus of claim 31 , wherein the bottom surface of the heat block comprises a metal plate.
33. The apparatus of claim 31 , further comprising a lid adapted to cover the top surface of the heat block, wherein the lid comprises a second heating element.
34. The apparatus of claim 31 , further comprising an optical assembly wherein the optical assembly comprises a light emitter configured to direct light into a sample vessel positioned in a receptacle of the one or more receptacles and an optical detector configured to detect light emitted from the sample vessel.
35. The apparatus of claim 31 , wherein the temperature control assembly comprises a resistive wire in thermal contact with the liquid composition.
36. The apparatus of claim 31 , wherein the liquid composition has a heat transfer coefficient of 0.1 to 4.5 W/m ° K.
37. A thermal cycler apparatus for performing a polymerase chain reaction (PCR) comprising:
a heat block having a top surface and a bottom surface, the heat block comprising:
one or more receptacles located on the top surface and configured to receive one or more sample vessels;
a container containing a liquid composition having a heat transfer coefficient of 0.1 to 5 W/m ° K, and wherein the container comprises a closed system with respect to the liquid composition; and
at least one stir bar configured to actively mix the liquid composition;
a heating element in thermal contact with the liquid composition; and
a temperature control assembly in communication with the heating element.
38. The apparatus of claim 37 , wherein the at least one stir bar comprises a horizontal stir bar, a fan shaped stir bar, or a stir bar that has multiple projections.
39. The apparatus of claim 37 , wherein the at least one stir bar is magnetically responsive.
40. The apparatus of claim 37 , wherein the at least one stir bar is mechanically connected to a motor.