# US 11,998,915 B2 · Microfluidic devices and methods for bioassays

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- Number: US 11,998,915 B2
- Document ID: US11998915B2
- Status: Granted
- Kind: B2
- Application number: 17/063,806
- Filed: 2020-10-06
- Published: 2021-02-04
- Granted: 2024-06-04
- Earliest claimed: 2011-05-06
- Assignees: Texas Tech University System
- Applicants: Texas Tech University System
- Inventors: Siva A. Vanapalli; Swastika S. Bithi
- Web page: https://patentgrep.com/patent/US11998915B2

## CPC

- B01L 3/502784: {specially adapted for droplet or plug flow, e.g. digital microfluidics}
- B01L 3/502715: {characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces}
- B01L 3/502746: {characterised by the means for controlling flow resistance, e.g. flow controllers, baffles or throttle valves}
- 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 3/502707: {characterised by the manufacture of the container or its components}
- B01L 2200/12: Specific details about manufacturing devices
- B01L 2200/142: Preventing evaporation
- B01L 2300/041: Connecting closures to device or container
- B01L 2300/0816: Cards, e.g. flat sample carriers usually with flow in two horizontal directions
- B01L 2300/087: Multiple sequential chambers
- B01L 2300/088: Channel loops
- B01L 2300/0887: Laminated structure
- B01L 2400/049: vacuum
- B01L 2400/084: Passive control of flow resistance
- B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE

## Abstract

A microfluidic device includes a substrate and a cover. The substrate has an inlet port, a first microchannel, one or more parking loops, a second microchannel and an outlet port for each microchannel network. The first microchannel is connected to the inlet port, the second microchannel is connected to the outlet port, the parking loops are connected between the first and second microchannels. Each parking loop includes a parking loop inlet, a parking loop output, a fluidic trap connected between the parking loop inlet and the parking loop outlet, and a bypass microchannel connected to the parking loop inlet and the parking loop outlet. The cover is attached to a top of the substrate and has an inlet opening and an outlet opening through the cover for each microchannel network. The inlet and outlet openings of the cover are disposed above the inlet and outlet ports in the substrate.

## Claims

### Claim 1

A microfluidic device comprising one or more microchannel networks, the microfluidic device comprising:
a substrate having an inlet port, a first microchannel, one or more parking loops, a second microchannel and an outlet port for each of the one or more microchannel networks, wherein the first microchannel is connected to the inlet port, the second microchannel is connected to the outlet port, the one or more parking loops are connected between the first microchannel and the second microchannel, and each of the one or more parking loops comprises a parking loop inlet, a parking loop output, a fluidic trap connected between the parking loop inlet and the parking loop outlet, and a bypass microchannel connected to the parking loop inlet and the parking loop outlet; and
a cover attached to a top of the substrate, the cover having an inlet opening and an outlet opening through the cover for each of the one more microchannel networks, wherein the inlet opening of the cover is disposed above and fluidly connected to the inlet port in the substrate and the outlet opening is disposed above and fluidly connected to the outlet port in the substrate.

### Claim 2 (depends on 1)

The microfluidic device as recited in claim 1, wherein the fluidic trap comprises:
a trap repository connected to the parking loop inlet; and
a trap microchannel connecting the trap repository to the parking loop outlet, wherein a cross-sectional area of the trap microchannel measured in a plane perpendicular to a longitudinal axis of the trap microchannel is smaller than a cross-sectional area of the bypass microchannel measured in a plane perpendicular to a longitudinal axis of the bypass microchannel.

### Claim 3 (depends on 2)

The microfluidic device as recited in claim 2, wherein the trap repository has a volume of about 10, 20, 30, 40, 50, 60, 70, 80 or 90 nL.

### Claim 4 (depends on 2)

The microfluidic device as recited in claim 2, wherein:
the first microchannel, the second microchannel and the bypass microchannel have a width of about 200 μm and a height of about 200 μm;
the trap repository has a diameter of about 450 μm;
the trap microchannel has a width of about 40 μm; and
the first microchannel, the second microchannel, the bypass microchannel, the trap repository and the trap microchannel have a height of about 200 μm.

### Claim 5 (depends on 4)

The microfluidic device as recited in claim 4, wherein the trap microchannel has a length of about 100 μm.

### Claim 6 (depends on 1)

The microfluidic device as recited in claim 1, wherein a hydrodynamic resistance ratio between the fluidic trap and the bypass microchannel is from 1.1 to 2.0, and a hydrodynamic resistance of the bypass microchannel is smaller than a hydrodynamic resistance of the fluidic trap.

### Claim 7 (depends on 1)

The microfluidic device as recited in claim 1, wherein a hydrodynamic resistance ratio between the fluidic trap and the bypass microchannel is from 1.4 to 1.6, and a hydrodynamic resistance of the bypass microchannel is smaller than a hydrodynamic resistance of the fluidic trap.

### Claim 8 (depends on 1)

The microfluidic device as recited in claim 1, wherein the one or more parking loops comprise at least four parking loops.

### Claim 9 (depends on 1)

The microfluidic device as recited claim 1, wherein the one or more microchannel networks comprise two or more microchannel networks forming an array of microchannel networks.

### Claim 10 (depends on 1)

The microfluidic device as recited in claim 1, wherein a diameter of the inlet opening and the outlet opening of the cover have a diameter of about 3 mm.

### Claim 11 (depends on 1)

The microfluidic device as recited in claim 1, wherein:
the inlet port in the substrate comprises a reservoir; and
the inlet opening of the cover is disposed above and fluidly connected to the reservoir in the substrate.

### Claim 12 (depends on 1)

The microfluidic device as recited in claim 1, further comprising a sample stored in the fluidic trap(s), wherein the cover reduces an evaporation of the sample stored in the fluidic trap(s) when compared with the sample stored in the fluidic trap(s) without the cover, and increases a viability of the sample stored in the fluidic trap(s) when compared with the sample stored in the fluidic trap(s) without the cover.

### Claim 13 (depends on 12)

The microfluidic device as recited in claim 12, wherein the evaporation of the sample stored in the fluidic trap(s) is less than 10% during 48 hours.

### Claim 14 (depends on 1)

A system comprising:
the microfluidic device as recited in claim 1; and
an automatically controlled pipette operable to interface with the inlet opening of the cover.

### Claim 15 (depends on 1)

A system comprising:
the microfluidic device as recited in claim 1; and
an automatically controlled pipette operable to interface with the outlet opening of the cover.