Microfluidic system for controlled fluid mixing and delivery

• US 20030106596A1
• Filed: 12/12/2001
• Published: 06/12/2003
• Est. Priority Date: 12/12/2001
• Status: Active Grant

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Hawkins, Gilbert A., Yang, Zhihao
• Granted Patent: US 6,622,746 B2
• Time in Patent Office: Days
• US Class Current: 137/828
• CPC Class Codes: F15C 5/00 Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• CPC Class Codes: F16K 2099/0074 using photolithography, e.g. etching
• CPC Class Codes: F16K 2099/0078 using moulding or stamping
• CPC Class Codes: F16K 2099/0084 Chemistry or biology, e.g. "lab-on-a-chip" technology
• CPC Class Codes: F16K 99/0001 Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0036 operated by temperature variations
• CPC Class Codes: Y10T 137/0335 Controlled by consistency of mixture
• CPC Class Codes: Y10T 137/2082 Utilizing particular fluid
• CPC Class Codes: Y10T 137/2196 Acoustical or thermal energy
• CPC Class Codes: Y10T 137/6606 With electric heating element
• CPC Class Codes: Y10T 137/7736 Consistency responsive

Abstract

A microfluidic system is provided for controlling delivery and mixing of thermally-responsive fluids. A plurality of microfluidic inlet channels open into a mixing chamber. A valve is associated with each of the inlet channels for controlling the flow of the thermally-responsive fluids through the inlet channels. The valves include a heater in thermal contact with at least a portion of the associated inlet channel, whereby the viscosity of the thermally-responsive fluids can selectively be controlled by heat to cause a change in flow of the thermally-responsive fluids through the inlet channels. A plurality of microfluidic outlet channels may be provided for transporting mixed fluids from the mixing chamber. A valve associated with each of the outlet channels controls the flow of the mixed thermally-responsive fluids through the outlet channels. These valves also include a heater in contact with at least a portion of the associated outlet channel, whereby said mixed thermally-responsive fluids can be directed from the mixing chamber selectively through each outlet channel.

Claims

1. A microfluidic system for controlling delivery and mixing of thermally-responsive fluids;

said system comprising;

a mixing chamber;

a plurality of microfluidic inlet channels opening into the mixing chamber and adapted to transport respectively different fluids into the mixing chamber; and

a valve associated with each of said microfluidic inlet channels and adapted to control the flow of the thermally-responsive fluids through the microfluidic inlet channels, said valves including a heater in thermal contact with at least a portion of the associated microfluidic inlet channel, whereby the viscosity of said thermally-responsive fluids can selectively be controlled by heat from said heater to cause a change in flow of said thermally-responsive fluids through said microfluidic inlet channels.

2. A microfluidic system as set forth in claim 1 wherein the thermally-responsive fluids are thickened by heat from said heater to cause a reduction in flow of said thermally-responsive fluids through said microfluidic inlet channels.

3. A microfluidic system as set forth in claim 1 wherein the fluids comprise a material and a thermally-responsive carrier fluid.

4. A microfluidic system as set forth in claim 1 wherein the fluid channels have an internal cross-sectional dimensional between about 0.1 μ

m and about 500 μ

m.

5. A microfluidic system as set forth in claim 1 wherein the fluid channels have an internal cross-sectional dimensional between about 1 μ

m and about 200 μ

m.

6. A microfluidic system as set forth in claim 1 wherein said thermally-responsive fluid is gelled by heat from said heater.

7. A microfluidic system as set forth in claim 1 wherein said heaters are contained in said microfluidic inlet channels.

8. A microfluidic system as set forth in claim 1 wherein said channels are enclosed by silicon, glass, polyimide, quartz, ceramic, polymethylmethacrylate, polydimethylsiloxane or photoresist material.

9. A microfluidic system as set forth in claim 1 wherein said channels are partially enclosed.

10. A microfluidic system as set forth in claim 1 wherein said channels are grooves.

11. A microfluidic system as set forth in claim 1 further comprising:

a plurality of microfluidic outlet channels communicating with the mixing chamber and adapted to transport mixed fluids from the mixing chamber; and

a valve associated with each of said microfluidic outlet channels for controlling the flow of the mixed thermally-responsive fluids through the microfluidic outlet channels, said valves including a heater in contact with at least a portion of the associated microfluidic outlet channel, whereby said mixed thermally-responsive fluids can be directed from the mixing chamber selectively through each outlet channel.

12. A method for controlling delivery and mixing of thermally-responsive fluids;

said method comprising the steps of;

flowing respectively different thermally-responsive fluids along a plurality of microfluidic inlet channels opening into a mixing chamber, and

selectively activating heaters which are in thermal contact with associated microfluidic inlet channels so as to control the flow of the thermally-responsive fluids through the microfluidic inlet channels.

13. A method as set forth in claim 12 further comprising selectively activating heaters which are in thermal contact with associated microfluidic outlet channels from the mixing chamber so as to control the flow of the thermally-responsive fluids from the mixing chamber along the microfluidic outlet channels.