Device and Method for Performing Digital PCR

Abstract

A micro-fluidic device 100 for performing digital PCR is presented. The device comprises: a semiconductor substrate; a first micro-fluidic channel 104, comprising an inlet 102 and an outlet 103, embedded in the semiconductor substrate; a heating element 101 thermally coupled to the first micro-fluidic channel 104; a droplet generator 107 connected to the inlet 102 of the first micro-fluidic channel 104 for generating droplets and pumping generated droplets at a flow rate into the first micro-fluidic channel 104; characterized in that: the heating element 101 is a single heating element connected to a temperature control unit 111 configured to cycle the temperature of the complete first micro-fluidic channel 104 through at least two temperature values; and wherein the flow rate of the droplet generator 107 is adaptable. Further, a method to perform digital PCR is presented using the micro-fluidic device 100.

1 . A micro-fluidic device for performing digital Polymerase Chain Reaction (PCR), the device comprising:
 a semiconductor substrate;   a first micro-fluidic channel, comprising an inlet and an outlet, embedded in the semiconductor substrate;   a heating element thermally coupled to the first micro-fluidic channel; and   a droplet generator connected to inlet of the first micro-fluidic channel for generating droplets and pumping generated droplets at a flow rate into the first micro-fluidic channel;   wherein the heating element is a single heating element connected to a temperature control unit configured to cycle the temperature of the complete first micro-fluidic channel through at least two temperature values; and wherein the flow rate of the droplet generator is adaptable.   
     
     
         2 . The micro-fluidic device according to  claim 1 , further comprising a second micro-fluidic channel connected on one side to an outlet of the droplet generator and on the other side to the inlet of the first micro-fluidic channel; and a heating element located to heat generated droplets present in the second micro-fluidic channel. 
     
     
         3 . The micro-fluidic device according to  claim 1 , further comprising a detector located for detecting droplets containing PCR products during PCR in the first micro-fluidic channel. 
     
     
         4 . The micro-fluidic device according to  claim 3 , wherein the detector is located at the outlet of the first micro-fluidic channel for detecting droplets containing PCR products. 
     
     
         5 . The micro-fluidic device according to  claim 3 , further comprising a computing unit connected to the detector; and wherein the computing unit is configured for determining the percentage of droplets containing PCR products. 
     
     
         6 . The micro-fluidic device according to  claim 5 , wherein the droplet generator is connected to the computing unit and the droplet generator is reconfigurable for changing the number of copies of an analyte in droplets. 
     
     
         7 . The micro-fluidic device according to  claim 1 , further comprising at least one through-substrate trench at least partially surrounding the first micro-fluidic channel. 
     
     
         8 . A method for performing a PCR on a fluid sample using a micro-fluidic device according to any of the preceding claims, the method comprising:
 providing a fluid sample in the micro-fluidic device;   generating droplets of the fluid sample and pumping the droplets into the first micro-fluidic channel using the droplet generator ; and   cycling the temperature of the complete first micro-fluidic channel through at least two temperature values using the single heating element.   
     
     
         9 . The method according to  claim 8 , wherein generating droplets and pumping droplets is stopped when the micro-fluidic channel is completely filled with droplets. 
     
     
         10 . The method according to  claim 8 , wherein cycling the temperature of the first micro-fluidic channel is performed until a saturation level of an analyte in a droplet is reached. 
     
     
         11 . The method according to  claim 8 , wherein cycling the temperature of the first micro-fluidic channel comprises continuously cycling the temperature of the first micro-fluidic channel through at least two temperature values while pumping droplets into the first micro-fluidic channel. 
     
     
         12 . The method according to  claim 8 , wherein the droplets are pumped in the first micro-fluidic channel at a flow rate adapted to a duration of the temperature cycling of the first micro-fluidic channel. 
     
     
         13 . The method according to  claim 8 , further comprising: pre-heating the generated droplets before pumping the droplets into the first micro-fluidic channel. 
     
     
         14 . The method according to  claim 8 , further comprising detecting droplets containing PCR products using the detector. 
     
     
         15 . The method according  claim 14  wherein the number of copies an analyte in droplets is changed by the droplet generator depending on the percentage of droplets containing PCR products determined by the computing unit.