Microfluidic system for controlled fluid mixing and delivery

• US 6,622,746 B2
• Filed: 12/12/2001
• Issued: 09/23/2003
• Est. Priority Date: 12/12/2001
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Hawkins, Gilbert A., Yang, Zhihao
• Primary Examiner(s): CHAMBERS, A MICHAEL
• Application Number:
  US10/021,457
• Publication Number:
  US 20030106596A1
• Time in Patent Office: 650 Days
• Field of Search: 137/828, 137/807, 137/4, 137/467.5, 137/341, 251/11
• US Class Current: 137/4
• 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 method for controlling delivery and mixing of thermally-responsive liquids;

said method comprising the steps of;

flowing respectively different thermally-responsive liquids 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 liquids through the microfluidic inlet channels.

2. A method as set forth in claim 1 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 liquids from the mixing chamber along the microfluidic outlet channels.

3. 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.

4. A microfluidic system as set forth in claim 3 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.

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

6. A microfluidic system as set forth in claim 3 wherein the fluid channels have an internal cross-sectional dimensional between about 0.1 μ

m and about 500 μ

m.

7. A microfluidic system as set forth in claim 3 wherein the fluid channels have an internal cross-sectional dimensional between about 1 μ

m and about 200 μ

m.

8. A microfluidic system as set forth in claim 3 wherein said thermally-responsive fluid is gelled by heat from said heater.

9. A microfluidic system as set forth in claim 3 wherein said heaters are contained in said microfluidic inlet channels.

10. A microfluidic system as set forth in claim 3 wherein said channels are enclosed by silicon, glass, polyimide, quartz, ceramic, polymethylmethacrylate, polydimethylsiloxane or photoresist material.

11. A microfluidic system as set forth in claim 3 wherein said channels are partially enclosed.

12. A microfluidic system as set forth in claim 3 wherein said channels are grooves.

13. A microfluidic system as set forth in claim 3 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.