Apparatus and Method for Segmented Thermal Cycler

Abstract

The present invention relates to a thermal cycler for the carrying out of chemical or biological reactions, such as PCR or other nucleic acid amplification reactions, that is segmented with a plurality of reaction vessel receiving elements. The reaction vessel receiving elements are thermally isolated from each other and provide an airtight seal to prevent liquids or moisture from penetrating below the reaction vessel receiving elements. The reaction vessel receiving elements have several recesses arranged in a pattern to receive the reaction vessels of a single standard microtiter plate and the segmented thermal cycler has a system for independently heating and cooling each of the reaction vessel receiving elements.

1 . A thermal cycler for processing biological or chemical samples comprising:
 a plurality of reaction vessel receiving elements configured to receive one standard microtiter plate;   a plurality of thermoelectric cooling devices (TEC) disposed to correspond to each of the plurality of reaction vessel receiving elements, wherein the TEC provides heating and cooling;   a drip pan positioned above the TECs and framing the plurality of reaction vessel receiving elements;   a single gasket to seal the plurality of reaction vessel receiving elements, wherein the gasket has a convex construction; and   a clamp to provide lateral force to compress the gasket between the reaction vessel receiving elements,   
     wherein the gasket forms an airtight seal between each of the plurality of reaction vessel receiving elements and between the drip pan and the plurality of reaction vessel receiving elements to isolate the plurality of TECs from environmental conditions above the drip pan and the plurality of reaction vessel receiving elements, and wherein the gasket is composed of non-thermally conducting material and separates adjacent reaction vessel receiving elements to provide thermal isolation between adjacent reaction vessel receiving elements. 
   
   
       2 . The thermal cycler of  claim 1 , further comprising one or more temperature sensors disposed in each reaction vessel receiving element. 
   
   
       3 . The thermal cycler of  claim 1 , further comprising a heating element disposed in each reaction vessel receiving element, wherein the heating element provides fine heating to a control temperature. 
   
   
       4 . The thermal cycler of  claim 1 , further comprising:
 a plurality of power amplifiers; and   a switch for each of the plurality of reaction vessel receiving elements to direct a current flow from the plurality of power amplifiers to the TEC.   
   
   
       5 . The thermal cycler of  claim 1 , wherein the reaction vessel receiving elements comprises a flat surface sample block. 
   
   
       6 . The thermal cycler of  claim 1 , wherein the thermoelectric cooling devices corresponding to each of the reaction vessel receiving elements are integrated into a single unit. 
   
   
       7 . The thermal cycler of  claim 6 , wherein the thermoelectric cooling devices each comprise dicing. 
   
   
       8 . The thermal cycler of  claim 1 , wherein the reaction vessel receiving elements are formed by one of metal injection molding (MIM), machining, and electroforming. 
   
   
       9 . The thermal cycler of  claim 1 , further comprising an excitation light source and a detector for monitoring real-time PCR. 
   
   
       10 . The thermal cycler of  claim 9 , further comprising imaging optics optically coupling the samples in the plurality of segments with a CCD. 
   
   
       11 . The thermal cycler of  claim 9 , further comprising a scanning head optically coupling the samples in the plurality of segments by movement over those segments. 
   
   
       12 . A method for processing biological or chemical samples comprising:
 positioning a single standard microtiter plate on a plurality of reaction vessel receiving elements of a thermal cycler;   independently heating and cooling the plurality of reaction vessel receiving elements with a plurality of thermoelectric cooling devices (TEC);   sealing the area below the plurality of reaction vessel receiving elements with a drip pan, a gasket, and a clamp, wherein the gasket has a convex portion and the clamp provides a lateral force to compress the gasket between the reaction vessel receiving elements to form an airtight seal between each of the plurality of reaction vessel receiving elements; and   thermally isolating adjacent reaction vessel receiving elements by constructing the gasket from a non-thermally conducting material.   
   
   
       13 . The method of  claim 12 , further comprising:
 annealing samples in a first portion of the microtiter plate at a first annealing temperature by cooling a first reaction vessel receiving element; and   annealing samples in a second portion of the microtiter plate at a second annealing temperature by cooling a second reaction vessel receiving element, wherein the second annealing temperature is not equal to the first annealing temperature.   
   
   
       14 . The method of  claim 12 , further comprising:
 elongating samples in a first portion of the microtiter plate at a first elongation temperature by heating a first reaction vessel receiving element; and   elongating samples in a second portion of the microtiter plate at a second elongation temperature by heating a second reaction vessel receiving element, wherein the second elongation temperature is not equal to the first elongation temperature.   
   
   
       15 . The method of  claim 12 , further comprising:
 repeating for a first number of cycles at least one of the steps of denaturing, annealing, and elongating samples in a first portion of the microtiter plate corresponding to a first reaction vessel receiving element; and   repeating for a second number of cycles at least one of the steps of denaturing, annealing, and elongating samples in a second portion of the microtiter plate corresponding to a second reaction vessel receiving element, wherein the first number of cycles is not equal to the second number of cycles.   
   
   
       16 . The method of  claim 12 , wherein a rate of cooling of a first reaction vessel receiving element is not equal to the rate of cooling of a second reaction vessel receiving element. 
   
   
       17 . The method of  claim 12 , wherein a rate of heating of a first reaction vessel receiving element is not equal to the rate of heating of a second reaction vessel receiving element. 
   
   
       18 . The method of  claim 12 , wherein the samples in a first reaction vessel receiving element have a different volume than the samples in a second reaction vessel receiving element. 
   
   
       19 . The method of  claim 12 , wherein a first reaction vessel receiving element is kept at a first residence time for annealing samples and a second reaction vessel receiving element is kept at a second residence time for annealing samples. 
   
   
       20 . The method of  claim 12 , wherein a first reaction vessel receiving element is kept at a first residence time for elongating samples and a second reaction vessel receiving element is kept at a second residence time for elongating samples.