Method for thermally cycling samples of biological material with substantial temperature uniformity

Abstract

An apparatus for thermally cycling samples of a biological material including a thermal block assembly including a plurality of sample holders for receiving samples of biological material; a heat sink thermally coupled to the thermal block assembly, the heat sink transferring heat away from the thermal block assembly to ambient air in contact with the heat sink; a first heat source thermally coupled to the thermal block assembly to provide heat to the thermal block assembly; and a second heat source thermally coupled to the first heat source and configured to provide heat to a portion of the first heat source. The arrangement of the heat sink, first heat source and second heat source can provide substantial temperature uniformity among the plurality of sample holders. The invention also includes a method for thermally cycling samples of biological material.

1 . A method for thermally cycling samples of biological material comprising: 
 inserting at least one sample of biological material into a sample holder of a thermal block assembly;    measuring a temperature of the thermal block assembly at at least one location on the thermal block assembly;    calculating a desired temperature of the thermal block assembly;    comparing the desired temperature with the measured temperature;    applying a first heat source to heat the thermal block assembly; and    applying a second heat source, a portion of the heat from the second heat source being transferred to the first heat source.    
   
   
       2 . The method of  claim 1  wherein the first heat source and the second heat source are applied if the measured temperature is less than the desired temperature.  
   
   
       3 . The method of  claim 1  wherein a portion of the heat from the first heat source is transferred to the thermal block assembly.  
   
   
       4 . The method of  claim 1  further comprising applying a third heat source, a portion of the heat from the third heat source being transferred to the sample holders.  
   
   
       5 . The method of  claim 1  further comprising cooling the thermal block assembly by imparting a cooling convection current on a heat sink which is thermally coupled to the thermal block assembly.  
   
   
       6 . The method of  claim 5  wherein the arrangement of the heat sink, first heat source and second heat source provides substantial temperature uniformity among the plurality of sample holders.  
   
   
       7 . The method of  claim 1  further comprising transferring heat from the thermal block assembly to ambient air in contact with a heat sink.  
   
   
       8 . The method of  claim 1  further comprising using a heat sink to cool the thermal block assembly when the measured temperature is greater than the desired temperature.  
   
   
       9 . The method of  claim 1  further comprising repeating the steps of measuring, calculating, and comparing until a predetermined thermal cycle for the samples of biological material is completed.  
   
   
       10 . A method for thermally cycling samples of biological material comprising: 
 inserting a plurality of samples of biological material into a thermal block assembly;    measuring the temperature of the thermal block assembly at at least one location on the thermal block assembly;    comparing the measured temperature of the thermal block assembly with a desired temperature;    heating the thermal block assembly with a first heat source;    heating the first heat source with a portion of the heat from a second heat source;    heating the thermal block assembly with a portion of the heat from a third heat source; and    repeating the steps of measuring, calculating, and comparing until completing a predetermined thermal cycle for the samples of biological material.    
   
   
       11 . The method of  claim 10  further comprising cooling the thermal block assembly by imparting a cooling convection current on a heat sink which is thermally coupled to the thermal block assembly.  
   
   
       12 . The method of  claim 11  wherein the arrangement of the heat sink, first heat source and second heat source provides substantial temperature uniformity among the plurality of sample holders.  
   
   
       13 . The method of  claim 10  further comprising transferring heat from the thermal block assembly to ambient air in contact with a heat sink.  
   
   
       14 . The method of  claim 10  further comprising using a heat sink to cool the thermal block assembly when the measured temperature is greater than the desired temperature.  
   
   
       15 . A method for thermally cycling samples of biological material in an apparatus with at least one sample holder located in a thermal block assembly comprising: 
 inserting at least one sample of biological material into a sample holder of the apparatus;    measuring the temperature of the thermal block assembly at multiple locations;    calculating the desired temperature of the thermal block assembly;    comparing the desired temperature with the measured temperature, and if the measured temperature is less than the desired temperature, the method further comprises:    applying a first heat source, a portion of the heat from the first heat source being transferred to the thermal block assembly;    applying a second heat source, a portion of the heat from the second heat source being transferred to the first heater; and    applying a third heat source, a portion of the heat from the third heat source being transferred to the sample holders;    if the measured temperature is greater than the desired temperature, the method further comprises cooling the thermal block assembly by imparting a cooling convection current on a heat sink which is thermally coupled to the thermal block assembly to provide heat transfer from the thermal block assembly to ambient air in contact with the heat sink; and    repeating the steps of measuring, calculating, and comparing until the predetermined thermal cycle for the samples of biological material is completed.    
   
   
       16 . The method of  claim 15  further comprising heating a heat sink located below the second heat source.  
   
   
       17 . The method of  claim 16  further comprising transferring a portion of the heat from the heat sink to the first heat source.  
   
   
       18 . The method of  claim 15  wherein the first heat source includes a plurality of heaters.  
   
   
       19 . The method of  claim 15  further comprising cooling the thermal block assembly with the first heat source.  
   
   
       20 . The method of  claim 15  further comprising inserting a sample tube containing a biological reaction mixture into a sample well of the thermal block assembly.