# US 11,027,278 B2 · Methods for controlling fluid flow in a microfluidic system

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- Number: US 11,027,278 B2
- Document ID: US11027278B2
- Status: Granted
- Kind: B2
- Application number: 16/584,315
- Filed: 2019-09-26
- Published: 2020-03-19
- Granted: 2021-06-08
- Earliest claimed: 2002-04-17
- Assignees: Cytonome/St, LLC
- Applicants: Cytonome/St, LLC
- Inventors: John R. Gilbert; Sebastian Böhm; Manish Deshpande
- Web page: https://patentgrep.com/patent/US11027278B2

## CPC

- B01L 3/502746: {characterised by the means for controlling flow resistance, e.g. flow controllers, baffles or throttle valves}
- B01L 3/502738: {characterised by integrated valves (throttle valves in microfluidic sample containers B01L3/502746)}
- F16K 99/0019: {Valves using a microdroplet or microbubble as the valve member}
- F16K 99/0061: {actuated by an expanding gas or liquid volume}
- B01L 3/502715: {characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces}
- B01L 2200/0605: Metering of fluids
- B01L 2300/0816: Cards, e.g. flat sample carriers usually with flow in two horizontal directions
- B01L 2300/0858: Side walls
- B01L 2400/06: Valves, specific forms thereof
- B01L 2400/082: Active control of flow resistance, e.g. flow controllers
- F16K 2099/0084: {Chemistry or biology, e.g. "lab-on-a-chip" technology}
- B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)}

## Abstract

A microfluidic device includes a microchannel having an interior bounded by a side wall, an inlet, a switching region, and a plurality of outlet channels downstream of the switching region. The microchannel is formed in a microfluidic chip substrate and configured to accommodate a flow of liquid through the microchannel. The microfluidic device includes a valve operatively coupled to the switching region comprising a sealed reservoir. A side passage extends between the reservoir and the interior of the microchannel via an aperture in the side wall and is configured to accommodate a volume of liquid between the interior of the microchannel and the reservoir. The microfluidic device includes an actuator integrated into the microfluidic chip and configured to increase an internal pressure of the reservoir and move at least a portion of the volume of the liquid from the side passage into the microchannel to deflect a portion of the liquid flowing through the microchannel.

## Claims

### Claim 1

A method for controlling liquid flow in a microfluidic device, comprising:
flowing a liquid through a microchannel formed in a microfluidic chip substrate, the microchannel having an interior bounded by a side wall, an inlet, a switching region, and a plurality of outlet channels downstream of the switching region; and
actuating a valve operatively coupled to the switching region, the valve including a sealed reservoir and a side passage extending between the sealed reservoir and the interior of the microchannel via an aperture in the side wall,
whereby actuating the valve increases or decreases an internal pressure of the sealed reservoir to cause a momentary flow disruption in the microchannel to deflect the liquid flowing therein.

### Claim 2 (depends on 1)

The method of claim 1, wherein actuating the valve includes using an actuator integrated in the microfluidic chip.

### Claim 3 (depends on 1)

The method of claim 1, wherein actuating the valve includes using an actuator operatively coupled with the microfluidic chip.

### Claim 4 (depends on 1)

The method of claim 1, wherein actuating the valve causes a volume of liquid to move from the side passage into the microchannel to cause the momentary flow disruption.

### Claim 5 (depends on 1)

The method of claim 1, wherein increasing the internal pressure of the sealed reservoir using the actuator varies the volume of the sealed reservoir.

### Claim 6 (depends on 1)

The method of claim 1, wherein actuation of the valve does not block the flow of liquid through the microchannel.

### Claim 7 (depends on 1)

The method of claim 1, wherein using the actuator comprises one of using a piezoelectric actuator and using an electromagnetic actuator.

### Claim 8 (depends on 1)

The method of claim 1, wherein the sealed reservoir includes a movable wall, and
wherein increasing the internal pressure of the sealed reservoir using the actuator includes deflecting the movable wall.

### Claim 9 (depends on 1)

The method of claim 1, wherein increasing the internal pressure of the sealed reservoir using the actuator includes flexing a flexible membrane.

### Claim 10 (depends on 1)

The method of claim 1, wherein increasing the internal pressure of the reservoir generates a pressure pulse within the switching region, and
wherein the pressure pulse travels across the flow direction of the liquid flowing through the microchannel.

### Claim 11 (depends on 1)

The method of claim 1, wherein flowing a liquid through a microchannel includes flowing a stream of particles in a carrier fluid through the microchannel, and
wherein, increasing the internal pressure of the reservoir selectively deflects a particle having a predetermined characteristic from the stream of particles using a pressure pulse.

### Claim 12 (depends on 11)

The method of claim 11, further comprising absorbing the pressure pulse using a second reservoir.