Instrument for performing a polymerase chain reaction using a microfluidic chip fabricated with printed circuit board techniques

Abstract

Techniques are provided for a microfluidic chip for performing a microfluidic reaction. The microfluidic chip includes a rigid layer, a first polymer layer that forms a first surface of a microfluidic chamber within the microfluidic chip, a first adhesive layer disposed between the rigid layer and the first polymer layer, and a second polymer layer that forms a second surface of the microfluidic chamber, and a first port connecting an exterior of the microfluidic chip to the microfluidic chamber through at least the rigid layer, the first polymer layer, and the first adhesive layer. A first self-sealing valve is formed in the first polymer layer and disposed within the first port, the first self-sealing valve configured to seal directly against the rigid layer through a first gap in the first adhesive layer in response to pressure from thermal expansion of a fluid within the microfluidic chamber.

What is claimed is: 
     
         1 . A microfluidic chip for performing a microfluidic reaction comprising:
 a first polymer layer that forms a first surface of a microfluidic chamber within the microfluidic chip;   a second polymer layer that forms a second surface of the microfluidic chamber;   a first conductive layer comprising:
 a first heater element positioned to heat a fluid contained within the microfluidic chamber; 
 a chip-portion of a drive circuit that is completed when the microfluidic chip is coupled with an external controller; and 
 a chip-portion of a voltage sensing circuit that is completed when the microfluidic chip is coupled with the external controller; 
   wherein the external controller controls the first heater element using the drive circuit based on temperature calculations determined by the external controller using the voltage sensing circuit;   wherein the microfluidic chip includes a plurality of layers, comprising the first polymer layer, the second polymer layer, and first conductive layer, that are formed and laminated using PCB techniques.   
     
     
         2 . The microfluidic chip of  claim 1 , wherein the chip-portion of the voltage sensing circuit includes a four-point probe connection to accurately measure both current and voltage. 
     
     
         3 . The microfluidic chip of  claim 1 ,
 wherein the chip-portion of the drive circuit comprises a first set of traces to a first set of connection pads configured to couple with the external controller;   wherein the chip-portion of the voltage sensing circuit comprises a second set of traces to a second set of connection pads configured to couple with the external controller.   
     
     
         4 . The microfluidic chip of  claim 1 , wherein the chip-portion of the voltage sensing circuit includes traces that connect directly to the first heater element to reduce errors caused by voltage drop and resistance from other components of the chip-portion of the drive circuit. 
     
     
         5 . The microfluidic chip of  claim 1 , wherein the first conductive layer is adjacent to the second polymer layer. 
     
     
         6 . The microfluidic chip of  claim 1 , wherein the microfluidic reaction is a Polymerase Chain Reaction (PCR) reaction.