# US 9,517,465 B2 · Lateral cavity acoustic transducer based microfluidic switch

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- Number: US 9,517,465 B2
- Document ID: US9517465B2
- Status: Granted
- Kind: B2
- Application number: 13/613,623
- Filed: 2012-09-13
- Published: 2014-01-09
- Granted: 2016-12-13
- Earliest claimed: 2011-09-13
- Assignees: The Regents of the University of California
- Applicants: Maulik V. Patel; Armando R. Tovar; Abraham P. Lee
- Inventors: Maulik V. Patel; Armando R. Tovar; Abraham P. Lee
- Web page: https://patentgrep.com/patent/US9517465B2

## CPC

- B01L 3/502761: {specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads or physically stretching molecules}
- B01L 3/502738: {characterised by integrated valves (throttle valves in microfluidic sample containers B01L3/502746)}
- G01N 15/1484: {microstructural devices}
- B01L 2200/0636: Focussing flows, e.g. to laminate flows
- B01L 2200/0652: Sorting or classification of particles or molecules
- B01L 2300/0816: Cards, e.g. flat sample carriers usually with flow in two horizontal directions
- B01L 2400/0622: distribution valves, valves having multiple inlets and/or outlets, e.g. metering valves, multi-way valves
- G01N 15/149: specially adapted for sorting particles, e.g. by their size or optical properties
- G01N 2015/0053: {in liquids, e.g. trouble}
- Y10T 436/2575: Volumetric liquid transfer
- B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A microfluidic switching device that includes an upstream microfluidic channel configured to contain a liquid having particles therein and a plurality of outlet channels coupled to the upstream microfluidic channel at a junction. A dead-end side channel or LCAT is oriented generally perpendicular to the upstream microfluidic channel and coupled to the upstream microfluidic channel at the junction, the dead-end side channel having a gas contained therein. The device includes a transducer configured to apply an external source of acoustic energy. Actuation of the transducer effectuates symmetrical oscillation of a gas/liquid boundary at the junction. Preferably, the junction comprises a bifurcation with two outlets. Further, the LCAT has a leading edge and a trailing edge and wherein the trailing edge of the LCAT is substantially aligned with the bifurcation.

## Claims

### Claim 1

A microfluidic switching device comprising:
an upstream microfluidic channel configured to contain a liquid having particles therein;
at least three outlet channels coupled to the upstream microfluidic channel at a junction;
a first dead-end side channel oriented at an angle with respect to the upstream microfluidic channel and coupled to the upstream microfluidic channel at the junction, the first dead-end side channel having a gas contained therein;
a second dead-end side channel located on an opposing side of the upstream microfluidic channel as the first dead-end side channel, the second dead-end channel oriented at an angle with respect to the upstream microfluidic channel and coupled to the upstream microfluidic channel at the junction, the second dead-end side channel having a gas contained therein;
a transducer, wherein actuation of the transducer moves the particles laterally across the upstream microfluidic channel into one of the at least three outlet channels; and
wherein the upstream microfluidic channel, the at least three outlet channels, the first dead-end side channel, and the second dead-end side channel are formed in a polydimethylsiloxane (PDMS) substrate and the PDMS substrate is bonded to a glass substrate and the transducer is acoustically coupled to the glass substrate.

### Claim 2 (depends on 1)

The microfluidic switching device of claim 1, wherein the upstream microfluidic channel is coupled to a first sheathing channel and a second sheathing channel at an upstream location.

### Claim 3 (depends on 1)

The microfluidic switching device of claim 1, wherein the particles comprise cells.

### Claim 4 (depends on 1)

The microfluidic switching device of claim 1, further comprising an imager configured to image one or more of the at least three outlet channels.

### Claim 5 (depends on 1)

The microfluidic switching device of claim 1, wherein a switching rate of the microfluidic switching device is tunable.

### Claim 6 (depends on 1)

The microfluidic switching device of claim 1, wherein the transducer is actuated in an on state for a period of time between about one millisecond and about four milliseconds.

### Claim 7 (depends on 1)

The microfluidic switching device of claim 1, wherein the first dead-end side channel and the second dead-end side channel are oriented at an acute angle with respect to the upstream microfluidic channel.

### Claim 8 (depends on 1)

The microfluidic switching device of claim 1, wherein the first dead-end side channel and the second dead-end side channel are oriented at an obtuse angle with respect to the upstream microfluidic channel.

### Claim 9 (depends on 1)

The microfluidic switching device of claim 1, wherein the upstream microfluidic channel comprises a focusing zone.