Thermal cycler for PCR

• US 20070113880A1
• Filed: 01/17/2007
• Published: 05/24/2007
• Est. Priority Date: 03/28/1997
• Status: Active Grant

• Current Assignee: Applied Biosystems LLC (Thermo Fisher Scientific Incorporated)
• Original Assignee: Applera Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Fawcett, Adrian, Ferrara, Keith, Atwood, John, Noreiks, Richard, Hetherington, Paul, Olsen, Douglas, Wittmer, Charles, Widomski, John
• Granted Patent: US 9,044,753 B2
• Time in Patent Office: Days
• US Class Current: 136/203
• CPC Class Codes: B01L 2300/0829 Multi-well plates; Microtitration plates
• CPC Class Codes: B01L 2300/1822 using Peltier elements
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 3/50853 with covers or lids
• CPC Class Codes: B01L 7/52 with provision for submitting samples to a predetermined sequence of different temperatures, e.g. for treating nucleic acid samples amplification or hybridisation processes per se C12Q1/68; controlling sequential reactions for synthesis B01J19/0046
• CPC Class Codes: C12Q 1/686 Polymerase chain reaction [PCR]
• CPC Class Codes: F25B 21/04 reversible
• CPC Class Codes: F25B 2321/021 Control thereof
• CPC Class Codes: G01R 27/205 Measuring contact resistance of connections, e.g. of earth connections
• CPC Class Codes: G05D 23/1919 characterised by the type of controller
• CPC Class Codes: H10N 10/13 characterised by the heat-exchanging means at the junction
• CPC Class Codes: Y10T 137/1516 Thermo-electric

Abstract

An instrument for performing highly accurate PCR employing an assembly, a heated cover and an internal computer. The assembly is made up of a sample block, a number of Peltier thermal electric devices and heat sink, clamped together. The sample block temperature is changed exclusively by the thermoelectric devices controlled by the computer. The sample block is of low thermal mass and is constructed of silver. The Peltier devices are designed to provide fast temperature excursions over a wide range. The heat sink has a perimeter trench to minimize edge losses and is adjacent to a continuously variable fan. A perimeter heater is used to improve the thermal uniformity across the sample block to approximately ±0.2° C. A heated platen pushes down onto the tube caps to apply a minimum acceptable force for seating the tubes into the block, ensuring good thermal contact with the block. The force is applied about the periphery of the tube caps to prevent distortion of the caps during thermal cycling. The platen is heated to provided thermal isolation from ambient conditions and to prevent evaporation from the surface of the sample into the upper portion of the sample tube. A control algorithm manipulates the current supplied to the thermoelectric coolers such that the dynamic thermal performance of the block can be controlled so that pre-defined thermal profiles for the sample temperature can be executed. The sample temperature is calculated instead of measured using a design specific model and equations. The control software includes calibration diagnostics which permit variation in the performance of thermoelectric coolers from instrument to instrument to be compensated for such that all instruments perform identically. The block/heat sink assembly can be changed to another of the same or different design. The assembly carries the necessary information required to characterize its own performance in an on-board memory device, allowing the assembly to be interchangeable among instruments while retaining its precision operating characteristics. The instrument has a graphical user interface. The instrument monitors the thermoelectric devices and warns of changes in resistance that may result in failure.

Claims

1. An apparatus comprising:

an assembly for cycling a plurality of vials through a series of temperatures; and

a cover for applying a predetermined temperature to an upper portion of vials disposed in the assembly;

wherein the assembly comprises

a sample block configured to receive a plurality of vials, and

a Peltier thermoelectric device configured to heat and cool the sample block.

2. The apparatus of claim 1, further comprising a plurality of vials received in the sample block.

3. The apparatus of claim 2, wherein the cover is configured to apply a seating force to the plurality of vials.

4. The apparatus of claim 2, wherein the plurality of vials comprises a microtiter tray.

5. The apparatus of claim 2, wherein the plurality of vials further comprise a liquid reaction mixture disposed therein.

6. The apparatus of claim 5, wherein the liquid reaction mixture comprises polymerase chain reaction reagents.

7. The apparatus of claim 1, wherein the sample block comprises a plurality of sample wells configured to receive the plurality of vials.

8. The apparatus of claim 7, wherein the sample block comprises 96 sample wells.

9. The apparatus of claim 7, wherein the sample wells are arranged in an 8×

12 array.

10. The apparatus of claim 7, wherein the sample block comprises silver.

11. The apparatus of claim 7, wherein the sample block has a rectangular top surface.

12. The apparatus of claim 7, wherein the sample block comprises an upper support plate configured to connect to the tops of the sample wells and a bottom plate configured to connect to the bottoms of the sample wells.

13. The apparatus of claim 12, wherein the upper support plate and the sample wells are electroformed as a single piece.

14. The apparatus of claim 12, wherein the sample block has a thermal mass and the bottom plate comprises the bulk of the thermal mass of the sample block.

15. The apparatus of claim 1, wherein the Peltier thermoelectric device comprises a plurality of Peltier thermoelectric devices.

16. The apparatus of claim 15, wherein the plurality of Peltier thermoelectric devices are matched to within 0.2°

C.

17. The apparatus of claim 1, wherein the computing apparatus is further configured to control the temperature of the cover.

18. The apparatus of claim 1, wherein the assembly further comprises a heat sink and the Peltier thermoelectric device is positioned between the sample and the heat sink.

19. The apparatus of claim 18, further comprising a clamping mechanism positioned to clamp the peltier thermoelectric device between the sample block and the heat sink.

20. The apparatus of claim 1, further comprising a computing apparatus for controlling the temperature of the assembly, and wherein the Peltier thermoelectric device is controlled by the computing apparatus.