Pasting edge heater

1. An apparatus for thermally cycling, the apparatus comprising:

a sample retaining element comprising an upper surface and a bottom surface opposing the upper surface, wherein the upper surface is configured with a plurality of cavities, capable of receiving a plurality of sample wells, wherein each sample well can contain at least one biological sample, and wherein each cavity comprises a closed bottom, an open top and connected to adjacent cavities by ribs that form voids between the cavities;

at least one thermoelectric module coupled to the retaining element; and

a heater adhesively coupled to an edge surface in close proximity to the cavities located between the upper surface and the bottom surface of the sample retaining element.

2. The apparatus of claim 1 , wherein the heater and the at least one thermoelectric module are separately controlled.

3. The apparatus of claim 1 , wherein the heater is a resistive heater.

4. The apparatus of claim 1 , wherein the heater comprises a flexible element providing surface area contact to the perimeter of the retaining element.

5. The apparatus of claim 1 , wherein the thermoelectric module is coupled to the bottom surface of the retaining element and provides heating to the plurality of sample wells.

6. The apparatus of claim 5 , wherein the thermoelectric module further provides cooling to the plurality of sample wells.

7. The apparatus of claim 4 , wherein the heater heats the sample wells at the perimeter of the retaining element.

8. The apparatus of claim 7 , wherein the sample wells at the perimeter of the retaining element are essentially the same temperature as the wells in the center of the retaining element.

9. A system for thermal cycling of biological samples, the system comprising:

a retaining element providing cavities for receiving a plurality of sample wells containing biological material, the retaining element comprising an upper surface and a bottom surface opposing the upper surface, wherein the upper surface is configured with cavities, each cavity comprising a closed bottom, an open top and connected to adjacent cavities by ribs that form voids between the cavities;

a thermoelectric module coupled to the retaining element;

one or more heaters adhesively coupled to an edge surface between the upper surface and the bottom surface in proximity to the cavities at the perimeter of the retaining element;

an excitation light source adapted to induce fluorescent light to be emitted by the biological material during thermal cycling; and

a detector adapted to collect the emitted fluorescent light.

10. The system of claim 9 , wherein the heater and the thermoelectric module are separately controlled.

11. The system of claim 9 , wherein the heater is a resistive heater.

12. The system of claim 9 , wherein the heater heats the cavities at the perimeter of the retaining element.

13. The apparatus of claim 12 , wherein the sample wells at the perimeter of the retaining element are essentially the same temperature as the wells in the center of the retaining element.

14. A thermal cycler comprising:

a retaining element providing cavities each cavity comprising a closed bottom and an open top for receiving a plurality of sample wells wherein the sample wells can contain biological material, and wherein the retaining element comprises a top surface, a bottom surface opposing the top surface and a third surface located between the top surface and the bottom surface and wherein the cavities are connected to adjacent cavities by ribs that form voids between the cavities;

one or more thermoelectric devices coupled to the retaining element; and

a heater adhesively coupled to the third surface in proximity to the cavities at the perimeter of the retaining element.

15. The thermal cycler of claim 14 , wherein the one or more thermoelectric modules and the heater are separately controlled.