Method and apparatus for use in temperature controlled processing of microfluidic samples

Abstract

Embodiments of the invention comprise microfluidic devices, instrumentation interfacing with those devices, processes for fabricating that device, and methods of employing that device to perform PCR amplification. Embodiments of the invention are also compatible with quantitative Polymerase Chain Reaction (“qPCR”) processes. Microfluidic devices in accordance with the invention may contain a plurality of parallel processing channels. Fully independent reactions can take place in each of the plurality of parallel processing channels. The availability of independent processing channels allows a microfluidic device in accordance with the invention to be used in a number of ways. For example, separate samples could be processed in each of the independent processing channels. Alternatively, different loci on a single sample could be processed in multiple processing channels.

1 . A method for processing a microfluidic sample, comprising: 
 heating the microfluidic sample to a first temperature for a first predetermined time by contacting a predetermined portion of a microfluidic device with a first temperature controlled thermal element; and    heating the microfluidic sample to a second temperature for a second predetermined time by contacting the predetermined portion of the microfluidic device with a second temperature controlled thermal element.    
   
   
       2 . The method of  claim 1 , further comprising successively positioning the microfluidic device to contact the predetermined portion thereof with each of the thermal elements.  
   
   
       3 . The method of  claim 1 , further comprising successively positioning each of the thermal elements to contact the predetermined portion of the microfluidic device.  
   
   
       4 . The method of  claim 3 , wherein successively positioning each of the thermal elements includes selectively rotating a shaft to which the thermal elements are mounted.  
   
   
       5 . The method of  claim 3 , wherein successively positioning each of the thermal elements includes successively laterally translating and lifting the thermal elements.  
   
   
       6 . The method of  claim 1 , further comprising heating the microfluidic sample to a third temperature for a third predetermined period of time by contacting the predetermined portion of the microfluidic device with a third temperature controlled thermal element.  
   
   
       7 . The method of  claim 6 , wherein the microfluidic sample comprises a solution of a target DNA sequence, a plurality of PCR primers, a polymerase, and a plurality of nucleotides and: 
 heating the microfluidic sample to the first temperature for the first predetermined time includes denaturing the microfluidic sample;    heating the microfluidic sample to the second temperature for the second predetermined time includes annealing the microfluidic sample; and    heating the microfluidic sample to the third temperature for the third predetermined period of time includes extending the microfluidic sample.    
   
   
       8 . The method of  claim 6 , wherein heating the microfluidic sample to the first temperature for the first predetermined time includes heating the microfluidic sample to the temperature of 95° C. for approximately 10 minutes.  
   
   
       9 . The method of  claim 6 , wherein heating the microfluidic sample to the second temperature for the second predetermined time includes heating the microfluidic sample to 55° C. for 5-30 seconds.  
   
   
       10 . The method of  claim 6 , wherein heating the microfluidic sample to the third temperature for the third predetermined period of time includes heating the microfluidic sample to 72° C. for 4-10 seconds.  
   
   
       11 . The method of  claim 6 , wherein heating the microfluidic sample to the first temperature for the first predetermined period of time includes heating the microfluidic sample to 95° C. for 3-10 seconds.  
   
   
       12 . The method of  claim 1 , wherein the microfluidic sample comprises a solution of a target DNA sequence, a plurality of PCR primers, a polymerase, and a plurality of nucleotides and: 
 heating the microfluidic sample to the first temperature for the first predetermined time includes denaturing the microfluidic sample; and    heating the microfluidic sample to the second temperature for the second predetermined time includes annealing the microfluidic sample.    
   
   
       13 . The method of  claim 12 , wherein heating the microfluidic sample to the first temperature for the first predetermined time includes heating the microfluidic sample to the temperature of 95° C. for 10 minutes.  
   
   
       14 . The method of  claim 12 , wherein heating the microfluidic sample to the second temperature for the second predetermined time includes heating the microfluidic sample to 55° C. for 5-30 seconds.  
   
   
       15 . The method of  claim 1 , further comprising interposing an interface material between the respective thermal element and the microfluidic device prior to heating.  
   
   
       16 . The method of  claim 15 , wherein the interface material is a wax that melts at the lower of the predetermined temperatures, a compliant polymer, or a Berquest Sil-pad material.  
   
   
       17 . The method of  claim 1 , wherein at least one of heating the microfluidic sample to a first temperature and heating the microfluidic sample to a second temperature includes heating from below the microfluidic sample.  
   
   
       18 . The method of  claim 1 , wherein at least one of heating the microfluidic sample to a first temperature and heating the microfluidic sample to a second temperature includes heating from above the microfluidic sample.  
   
   
       19 . The method of  claim 1 , wherein at least one of heating the microfluidic sample to a first temperature and heating the microfluidic sample to a first temperature includes heating from above and below the microfluidic sample.  
   
   
       20 . The method of  claim 1 , further comprising fluorescently monitoring the microfluidic sample during at least one of the first and second predetermined time periods.  
   
   
       21 . The method of  claim 20 , wherein fluorescently monitoring the microfluidic sample includes fluorescently monitoring the microfluidic sample at a plurality of wavelengths.  
   
   
       22 . The method of  claim 21 , further comprising thermally ramping the microfluidic sample while fluorescently monitoring the microfluidic sample.  
   
   
       23 . The method of  claim 20 , further comprising thermally ramping the microfluidic sample while fluorescently monitoring the microfluidic sample.  
   
   
       24 . The method of  claim 1 , further comprising thermally ramping the microfluidic sample.  
   
   
       25 - 73 . (canceled)