Heater unit for microfluidic diagnostic system

Abstract

The present technology provides for a heater substrate that contains networks of heater elements configured to controllably and selectively deliver heat to one or more PCR reaction chambers in a microfluidic substrate with which the heater substrate makes contact. In exemplary embodiments, the heater substrate can deliver heat to 12, 24, 48, or 96 chambers independently of one another, or simultaneously. The heater substrate is located in a heater unit that may be introduced into a diagnostic apparatus that can receive and position a microfluidic substrate, such as in a cartridge, in contact with the heater unit, receive one or more polynucleotide containing samples into one or more lanes in the microfluidic substrate, and cause amplification of the polynucleotides to occur, and detect presence of absence of specified polynucleotides in the amplified samples.

What is claimed is: 
     
         1 . A heater unit, comprising:
 a substrate having embedded therein a plurality of groups of resistive heaters, and at least one temperature sensor per group of heaters;   and control circuitry for supplying electric current to the plurality of groups of resistive heaters at selected intervals, wherein the substrate has a surface configured to make thermal contact with a microfluidic cartridge having a plurality of PCR reaction chambers, and to deliver heat from the plurality of groups of resistive heaters to regions of the cartridge, such that each of the groups of resistive heaters delivers heat to a select PCR reaction chamber to perform a reaction, wherein the heat delivery from each group of resistive heaters is controlled by sensing temperature using the at least one temperature sensor of the group, and wherein at least one of the groups comprises a plurality of resistive heaters arranged in a shape similar to the shape of one of the PCR reaction chambers.   
     
     
         2 . The heater unit of  claim 1 , wherein the resistive heaters in the group arranged in a shape similar to the shape of one of the PCR reaction chambers are arranged to provide uniform heating in an area enclosed by the group. 
     
     
         3 . The heater unit of  claim 2 , wherein the area is between 1 mm 2  and 100 mm 2 . 
     
     
         4 . The heater unit of  claim 3 , wherein the resistive heaters of at least one of the groups are connected in series or parallel. 
     
     
         5 . The heater unit of  claim 1 , wherein at least one of the resistive heaters in a group of resistive heaters is also a temperature sensor. 
     
     
         6 . The heater unit of  claim 1 , wherein two adjacent heater groups are spaced apart by a distance to permit independent operation of their respective adjacent reaction chambers in the microfluidic cartridge. 
     
     
         7 . The heater unit of  claim 1 , wherein the reaction performed is thermocycling for PCR. 
     
     
         8 . The heater unit of  claim 7 , wherein one PCR heat cycle is performed in less than about 25 seconds. 
     
     
         9 . The heater unit of  claim 8 , wherein the PCR heat cycle time is reduced by forced cooling during the cooling part of the PCR cycle. 
     
     
         10 . The heater unit of  claim 1 , further comprising heaters to actuate other microfluidic components in the microfluidic cartridge, including valves, pumps, or gates. 
     
     
         11 . The heater unit of  claim 1 , further comprising a processor, wherein the processor is programmable to operate the control circuitry. 
     
     
         12 . The heater unit of  claim 1 , further comprising a compliant layer at the surface, configured to thermally couple the heater groups with at least a portion of a microfluidic cartridge in contact with the surface. 
     
     
         13 . A diagnostic apparatus configured to carry out PCR on a number of samples in parallel, wherein the apparatus utilizes a heater unit of  claim 1  to apply thermal cycling to each of the samples. 
     
     
         14 . A heater substrate comprising:
 a plurality of groups of resistive heaters, and   at least one temperature sensor per group of heaters,   wherein the substrate has a surface configured to make thermal contact with a microfluidic substrate having a plurality of PCR reaction chambers, and to deliver heat from one or more of the plurality of groups of resistive heaters to one or more of the PCR reaction chambers so that a PCR reaction takes place therein, and wherein the heat delivery from each group of resistive heaters is controlled by sensing temperature using the at least one temperature sensor of the group, and wherein the resistive heaters one of the groups of resistive heaters are arranged to maintain a uniform temperature within the PCR reaction chamber.   
     
     
         15 . The heater substrate of  claim 14 , wherein the substrate is made of one or more materials selected from the group consisting of: glass, fused silica, and quartz. 
     
     
         16 . The heater substrate of  claim 14 , wherein the plurality of groups of resistive heaters are arranged into lanes, such that each lane corresponds to a PCR reaction chamber in the microfluidic substrate. 
     
     
         17 . The heater substrate of  claim 16 , wherein there are 12, 24, 48, or 96 lanes. 
     
     
         18 . The heater substrate of  claim 16 , wherein the substrate comprises a heater chip and a printed circuit board. 
     
     
         19 . A heater substrate, comprising:
 a plurality of groups of resistive heaters, and at least one temperature sensor per group of heaters, wherein the group comprises at least one long heater and at least one short heater; and   control circuitry for supplying electric current to the plurality of groups of resistive heaters at selected intervals, wherein   the substrate has a surface configured to make thermal contact with a microfluidic cartridge having a plurality of PCR reaction chambers, and to deliver heat from the plurality of groups of resistive heaters to regions of the cartridge, such that each of the groups of resistive heaters delivers heat to a select PCR reaction chamber to perform a reaction, wherein the heat delivery from each group of resistive heaters is controlled by sensing temperature using the at least one temperature sensor of the group.   
     
     
         20 . The heater substrate of  claim 19 , wherein at least one of the resistive heaters in a group of resistive heaters is also a temperature sensor. 
     
     
         21 . A heater substrate, comprising:
 a plurality of groups of resistive heaters, and at least one temperature sensor per group of heaters, wherein the group comprises at least four heaters; and   control circuitry for supplying electric current to the plurality of groups of resistive heaters at selected intervals, wherein   the substrate has a surface configured to make thermal contact with a microfluidic cartridge having a plurality of PCR reaction chambers, and to deliver heat from the plurality of groups of resistive heaters to regions of the cartridge, such that each of the groups of resistive heaters delivers heat to a select PCR reaction chamber to perform a reaction, wherein the heat delivery from each group of resistive heaters is controlled by sensing temperature using the at least one temperature sensor of the group.   
     
     
         22 . The heater substrate of  claim 21 , wherein a group consists of two long heaters and two short heaters. 
     
     
         23 . The heater substrate of  claim 21 , wherein at least one of the resistive heaters in a group of resistive heaters is also a temperature sensor.