Heat-reduction methods and systems related to microfluidic devices

• US 8,110,158 B2
• Filed: 10/14/2010
• Issued: 02/07/2012
• Est. Priority Date: 02/14/2001
• Status: Active Grant

• Current Assignee: HandyLab Incorporated (Becton Dickinson & Co)
• Original Assignee: HandyLab Incorporated (Becton Dickinson & Co)
• Inventors: Handique, Kalyan
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): Handy, Dwayne K
• Application Number:
  US12/904,432
• Publication Number:
  US 20110038768A1
• Time in Patent Office: 481 Days
• Field of Search: 422/68.1, 422/82.01, 422/99, 422/100, 422/101, 422/102, 422/502, 422/503, 422/504, 422/547, 422/551, 422/552, 436/147, 436/174, 436/180, 204/400, 204/424, 204/425, 204/426, 204/451
• US Class Current: 422/504
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/1822 using Peltier elements
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 2300/1883 using thermal insulation
• CPC Class Codes: B01L 2300/1894 Cooling means; Cryo cooling
• CPC Class Codes: B01L 2400/0442 thermal energy, e.g. vaporisation, bubble jet
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: B01L 7/00 Heating or cooling apparatus autoclaves B01J3/04; Heat insulating devices
• CPC Class Codes: C12Q 1/6806 Preparing nucleic acids for analysis, e.g. for polymerase chain reaction [PCR] assay C12Q1/6804 takes precedence
• CPC Class Codes: H05B 3/22 non-flexible
• CPC Class Codes: H05K 3/10 in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A system and method for preventing or reducing unwanted heat in a microfluidic of the device while generating heat in selected regions of the device. In one example, current is supplied to a heating element through electric leads, wherein the leads are designed so that the current density in the leads is substantially lower than the current density in the heating element. This maybe accomplished using conductive leads which have a cross-sectional area which is substantially greater than the cross-sectional area of the heating element. In another example, unwanted heat in the microfluidic complex is reduced by thermally isolating the electric leads from the microfluidic complex. This maybe accomplished by running each lead directly away from the microfluidic complex, through a thermally isolating substrate. After the leads pass through the thermally isolating substrate, they are then routed to the current source. Thus, the thermally isolating substrate substantially blocks the transfer of heat from the leads to the microfluidic complex. In another example, unwanted heat is removed from selected regions of the microfluidic complex using one or more cooling devices. One or more Peltier cooling devices may be attached to a substrate to remove heat generated by heating elements and/or other electronic circuitry.

Claims

1. An integrated microfluidic processing system comprising a microfluidic device, the device comprising:

a microfluidic complex comprising at least one thermally actuated component, wherein at least one thermally actuated component is configured for moving fluid in the microfluidic device;

a thermally insulating substrate comprising a heating element configured to actuate the thermally actuated component;

at least one conductive lead for supplying electrical current from a current source to the heating element, wherein the lead has a lower current density that the heating element; and

a Peltier cooler configured to remove heat from specific regions of the microfluidic complex.

2. An integrated microfluidic system comprising a microfluidic device, the device comprising:

first and second substrates defining, therebetween, a microfluidic complex;

at least one heating element configured to heat a portion of the microfluidic complex, at least one heating element further configured for moving fluid in the microfluidic device;

at least one conductive lead for supplying electrical current from a current source to the heating element, wherein the lead has a lower current density that the heating element; and

one or more Peltier devices abutting one or both of the first and second substrates.

3. The system of claim 2, wherein the one or more Peltier devices are attached to the substrates with a heat-transfer paste.

4. The system of claim 2, wherein at least one of the Peltier devices is configured to cool the entire microfluidic complex.

5. The system of claim 2, wherein at least one of the Peltier devices is configured to cool a specific region of the microfluidic complex.

6. The system of claim 5, wherein the specific region includes a microchamber in the microfluidic complex.

7. The system of claim 2, comprising multiple Peltier devices abutting one of the first and second substrates.

8. The system of claim 2, comprising two or more Peltier devices, wherein the two or more Peltier devices are independently controllable.

9. The system of claim 2, wherein the heating element is contained within an insulating layer disposed between the first and second substrates.

10. The system of claim 2, further comprising an insulating layer adjacent one of the first and second substrates, wherein at least one of the one or more Peltier devices is attached to the insulating layer.

11. The system of claim 2, wherein the one or more Peltier devices are controlled electronically, or are battery operated.

12. The system of claim 2, further comprising a conductor in electrical communication with the heating element wherein at least a portion of the conductor is separated from the microfluidic complex by one of the first or second substrates.