Systems and methods for the amplification of dna

Abstract

A system for amplifying nucleic acids is disclosed which, in one embodiment, includes a fluidic device having a sample channel and a heat exchange channel disposed sufficiently close to the sample channel such that a heat exchange fluid in the heat exchange channel can cause a sample in the sample channel to gain or lose heat at desired levels. In one illustrative embodiment, the system further includes three reservoirs coupled to the heat exchange channel and a temperature control system configured to heat fluids stored in the respective reservoirs at different temperatures. One or more pumps and a controller are configured to cause fluid stored in the reservoirs to enter and flow through the heat exchange channel at different times.

What is claimed is: 
     
         1 . A method of amplifying DNA using a system comprising a fluidic device having a sample channel and a heat exchange channel that is used to heat and/or cool a sample in the sample channel, the method comprising:
 causing a sample of a test solution containing PCR reagents to move through the sample channel of the fluidic device; and   while the sample is moving through at least a section of the sample channel:   (1) for a first period of time, causing a first heat exchange fluid stored in a first container and regulated at a first temperature while stored in the first container to: (1) exit the first container and (2) move through the heat exchange channel after exiting the first container;   (2) for a second period of time, causing a second heat exchange fluid stored in a second container and regulated at a second temperature while stored in the second container to: (1) exit the second container and (2) move through the heat exchange channel after exiting the second container; and   (3) for a third period of time, causing a third heat exchange fluid stored in a third container and regulated at a third temperature while stored in the third container to: (1) exit the third container and (2) move through the heat exchange channel after exiting the third container, wherein   the first period of time may be different than the second period of time, which may be different than the third period of time, and   the first temperature is different than the second temperature, which is different than the third temperature.   
     
     
         2 . The method of  claim 1 , further comprising causing the first heat exchange fluid to enter the third container after exiting the heat exchange channel. 
     
     
         3 . The method of  claim 2 , further comprising causing the second heat exchange fluid to enter the first container after exiting the heat exchange channel. 
     
     
         4 . The method of  claim 3 , further comprising causing the third heat exchange fluid to enter the second container after exiting the heat exchange channel. 
     
     
         5 . The method of  claim 1 , further comprising causing the first heat exchange fluid to enter the first container after exiting the heat exchange channel. 
     
     
         6 . The method of  claim 5 , further comprising causing the second heat exchange fluid to enter the second container after exiting the heat exchange channel. 
     
     
         7 . The method of  claim 6 , further comprising causing the third heat exchange fluid to enter the third container after exiting the heat exchange channel. 
     
     
         8 . The method of  claim 1 , wherein the first temperature is a temperature such that when the first heat exchange fluid moves through the heat exchange channel said fluid heats a sample in the sample channel to a temperature over 80 degrees Celsius, the second temperature is a temperature such that when the second heat exchange fluid moves through the heat exchange channel said fluid cools a sample in the sample channel to a temperature under about 60 degrees Celsius, and the third temperature is a temperature such that when the third heat exchange fluid moves through the heat exchange channel said fluid heats a sample in the sample channel to a temperature between 60 and 80 degrees Celsius. 
     
     
         9 . The method of  claim 1 , wherein at least a portion of the heat exchange channel is beneath the sample channel and parallel with the sample channel. 
     
     
         10 . The method of  claim 1 , wherein at least one dimension of the heat exchange channel and the sample channel is less than about 3000 micrometers. 
     
     
         11 . The method of  claim 10 , wherein the heat exchange channel has a width between about 20 and 2000 micrometers and a depth between about 20 and 2000 micrometers. 
     
     
         12 . The method of  claim 1 , wherein said first heat exchange fluid is identical with the second heat exchange fluid, which is identical with the third heat exchange fluid, and the first heat exchange fluid comprises a gas and/or a liquid. 
     
     
         13 . The method of  claim 1 , wherein said heat exchange fluids comprise water and/or compressed air with pressure from 1 to 200 psia. 
     
     
         14 . The method of  claim 1 , wherein said first heat exchange fluid is different than the second heat exchange fluid, which can be the same or different than the third heat exchange fluid. 
     
     
         15 . A method of thermal exchange in a microfluidic chip comprising:
 directing a first heat exchange fluid at a first temperature through a heat exchange channel for a first period of time, wherein the heat exchange channel is configured to exchange heat with a portion of a sample channel, wherein at least one dimension of the heat exchange channel and the sample channel are less than 1000 micrometers;   directing a second heat exchange fluid at a second temperature through the heat exchange channel for a second period of time; and   directing a third heat exchange fluid at a third temperature through a heat exchange channel for a third period of time.