Proximal degas driven microfluidic actuation

Patent metadata

Field	Value
Publication number	US-2016144362-A1
Application number	US-201514947893-A
Country	US
Kind code	A1
Filing date	Nov 20, 2015
Priority date	May 23, 2013
Publication date	May 26, 2016
Grant date	—

Abstract

An apparatus with a self-contained, tunable, microfluidic pumping system that utilizes the high air permeability of the matrix material to actuate fluid flow in a network of fluidic microchannels and microstructures is provided. The pumping relies upon partial evacuation of degas/vacuum channels that are located next to the fluid channels to degas air from the fluid channels or structures producing a reduction of pressure in the fluidic channel leading to the flow of fluid from an inlet at atmospheric pressure through the device. The solution is isolated from the pumping apparatus since the liquid does not pass through the diffusion barriers. The apparatus and method can also provide bubble-free microfluidic pumping, without any auxiliary equipment or device pre-treatment, and can fill dead-end channels and chambers, providing a powerful liquid handling tool for a broad range of applications.

First claim

What is claimed is:

1 . A microfluidic apparatus, comprising:
(a) a gas permeable matrix; (b) at least one network of interconnected fluidic structures formed in the matrix with at least one input fluidic channel; (c) at least one network of degas microchannels located in proximity to said network of fluidic structures formed in the matrix; and (d) means for evacuating the degas microchannel network; wherein gases located in the network of fluidic structures diffuse into said evacuated degas channels creating a negative pressure and movement of fluid in the input fluidic channels and fluidic structures.

2 . An apparatus as recited in claim 1 , wherein said gas permeable matrix is a material selected from the group of materials consisting essentially of polydimethylsiloxane (PDMS), polymethylpentene (PMP), silicone elastomers, thermoplastic elastomers and rubber.

3 . An apparatus as recited in claim 1 , wherein said means for evacuating the degas microchannel networks comprises an external vacuum source selected from the group of a mechanical pump and a handheld bulb pump.

4 . An apparatus as recited in claim 1 , wherein said means for evacuating the degas microchannel networks comprises an integrated on-chip vacuum source of a membrane thumb pump and a one way air valve.

5 . An apparatus as recited in claim 1 , wherein an evacuated degas microchannel network pressure is in the range of between −30 kPa and −90 kPa gauge.

6 . An apparatus as recited in claim 1 , further comprising a membrane coupled to the gas permeable matrix.

7 . An apparatus as recited in claim 6 , wherein the membrane comprises a gas impermeable membrane made from materials selected from the group of materials consisting of synthetic rubber, Butynol and cyclic olefin copolymer (COC).

8 . An apparatus as recited in claim 6 , wherein the membrane has a thickness of between 0.05 mm and 2 mm.

9 . An apparatus as recited in claim 1 , wherein the fluidic microchannel networks have channel widths and heights within the range of between 30 μm and 250 μm.

10 . An apparatus as recited in claim 1 , wherein the proximity between the fluidic and degas microchannel networks is in the range of between 50 μm and 400 μm.

11 . A microfluidic apparatus, comprising:
(a) a first matrix having at least one network of interconnected fluidic structures formed in the matrix connected to at least one input fluidic channel; (b) a gas permeable barrier coupled to the first matrix; (c) a second matrix mounted to the gas permeable barrier, the second matrix having at least one network of degas microstructures; and (d) a vacuum source operably coupled to the network of degas microstructures configured to evacuate the degas network; wherein the network degas microstructures are located in proximity to the network of fluidic structures separated by the gas permeable barrier; and wherein gases located in the network of fluidic structures diffuse into said evacuated degas microstructures through the gas permeable barrier creating a negative pressure and movement of fluid in the input fluidic channels and fluidic structures.

12 . An apparatus as recited in claim 11 , further comprising a membrane coupled to the second matrix.

13 . An apparatus as recited in claim 12 , wherein the membrane comprises a gas impermeable membrane made from materials selected from the group of materials consisting of synthetic rubber, Butynol and cyclic olefin copolymer (COC).

14 . An apparatus as recited in claim 12 , wherein the membrane has a thickness of between 0.05 mm and 2 mm.

15 . An apparatus as recited in claim 11 , wherein said gas permeable barrier is a material selected from the group of materials consisting of elastomers, silicone elastomers, thermoplastic elastomers, polymethylpentene (PMP), gas permeable thermoplastics and rubber.

16 . An apparatus as recited in claim 11 , wherein said first matrix is a gas impermeable matrix and said second matrix is a gas impermeable matrix selected from the group of materials consisting of synthetic rubber, Butynol and cyclic olefin copolymer (COC).

17 . An apparatus as recited in claim 11 , wherein said first matrix is a gas impermeable matrix material selected from the group of materials consisting of synthetic rubber, Butynol and cyclic olefin copolymer (COC) and said second matrix is a gas permeable matrix material selected from the group of materials consisting of polydimethylsiloxane (PDMS), polymethylpentene (PMP), silicone elastomers, thermoplastic elastomers and rubber.

18 . An apparatus as recited in claim 11 , wherein said vacuum source for evacuating degas microchannel networks comprises an integrated on-chip vacuum source of a membrane thumb pump and a one way air valve.

19 . A method for actuation of a microfluidic device apparatus, comprising:
(a) providing a microfluidic device comprising:
(i) a microfluidic channel network and a degas channel network separated by at least one gas permeable wall;
(ii) at least one solution inlet coupled to the microfluidic channel network; and
(iii) a vacuum source configured to remove air from the degas channel network;
(b) placing a fluid into the solution inlet; (c) evacuating gasses out of the degas channel network with the vacuum source; and (d) allowing gases within the input fluidic channel to diffuse into the degas channels through gas permeable walls and decrease the pressure in the fluidic channel thereby causing the fluid in the solution inlet to move through the microfluidic structures of the array.

20 . A method as recited in claim 19 , further comprising:
optimizing the fluidic channel geometry; optimizing the degas channel geometry; and optimizing the wall thickness between the input fluidic channels and the degas channels for rapid and bubble free fluid flow over time.

Assignees

• Univ California

Inventors

• Lee Luke P
• Mitra Debkishore
• Waldeisen John R
• Liu Jixiao

Classifications

• B01D19/0031

  by filtration · CPC title

• B01L2300/0816

  Cards, e.g. flat sample carriers usually with flow in two horizontal directions · CPC title

• B01L2300/0858

  Side walls · CPC title

• B01L2300/069

  Absorbents; Gels to retain a fluid · CPC title

• B01L2400/0638

  membrane valves, flap valves · CPC title