# US 12,758,973 B2 · Micro-fluidic system using micro-apertures for high throughput detection of cells

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- Number: US 12,758,973 B2
- Document ID: US12758973B2
- Status: Granted
- Kind: B2
- Application number: 17/390,404
- Filed: 2021-07-30
- Published: 2022-01-20
- Granted: 2026-10-13
- Earliest claimed: 2011-04-05
- Assignees: Purdue Research Foundation
- Applicants: Purdue Research Foundation
- Inventors: Cagri A. Savran; Philip S. Low; Chun-Li Chang; Wanfeng Huang
- Web page: https://patentgrep.com/patent/US12758973B2

## 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 3/50273: {characterised by the means or forces applied to move the fluids}
- G01N 27/745: {for detecting magnetic beads used in biochemical assays (concerning the assays G01N33/54326; sensors therefor G01R33/1269; automatic analysers therefor G01N35/0098)}
- G01N 33/54326: {Magnetic particles}
- G01N 33/575: for cancer
- G01N 33/57555: of the prostate
- G01N 33/5759: {involving compounds localised on the membrane of tumour or cancer cells}
- B01L 2200/0652: Sorting or classification of particles or molecules
- B01L 2200/0668: Trapping microscopic beads
- B01L 2300/0877: Flow chambers
- B01L 2400/043: magnetic forces
- G01N 2001/4016: {being a selective membrane, e.g. dialysis or osmosis}
- 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)

## Abstract

A microfluidic detection system for micrometer-sized entities, such as biological cells, includes a detector component incorporating a plate with a plurality of opening, the plate separating two chambers, one in communication with a fluid source containing target entities bound to magnetic beads. The openings are sized to always permit passage of the magnetic beads therethrough into a lower one of the chambers and are further sized to always prevent passage of the target entities from the upper one of the chambers. The detector component further includes a magnet positioned to pull unbound magnetic beads through the openings and to capture target entities bound to magnetic beads on the surface of the plate. In a further feature, the microfluidic detection system is configured to pass target molecules through the plate to be bound to a functionalized surface of the lower chamber.

## Claims

### Claim 1

A microfluidic system for detecting first target entities and second target entities in a fluid sample containing a quantity of magnetic beads functionalized with one or more recognition elements capable of binding specifically to the first target entities or to the second target entities, the system comprising:
(a) a detector component including:
a body defining therein a reservoir; and
a sensor chip comprising a plate disposed within the reservoir and arranged to separate the reservoir into a first chamber and a second chamber, wherein the plate comprises a plurality of openings therethrough, wherein each opening is sized to permit passage of the magnetic beads and the second target entities and to prevent passage of the first target entities, and wherein the second chamber comprises a surface functionalized with recognition elements that selectively bind to the second target entities;
(b) a magnet disposed relative to the body so that the second chamber and the plate are situated between the magnet and the first chamber;
(c) a pump arranged to flow the fluid sample from one or more sources through a first inlet into the first chamber, over the plate, and out through a first outlet; and
(d) a control module configured to
control the magnet to generate a magnetic force sufficient to pull magnetic beads in the first chamber through the openings in the plate and into the second chamber, and sufficient to attract and to hold at least some of the first target entities bound to one or more magnetic beads against a surface of the plate, and
control the pump to generate a flow rate of the fluid sample sufficient to permit magnetic beads not bound to a first target entity to be pulled through the plate into the second chamber, and sufficient to flow fluid sample over the plate and out of the first chamber through the first outlet without dislodging first target entities bound to magnetic beads from the surface of the plate.

### Claim 2 (depends on 1)

The microfluidic system of claim 1, wherein the control module follows a controlled flow protocol according to a particular type of target entity, recognition element, and sample size.

### Claim 3 (depends on 1)

The microfluidic system of claim 1, wherein the control module is configured to allow user controlled operation.

### Claim 4 (depends on 1)

The microfluidic system of claim 1, wherein the pump is arranged and controlled to flow different fluid samples from multiple sources, and wherein the system further comprises one or more valves to connect the multiple sources to the first inlet of the first chamber of the detector component.

### Claim 5 (depends on 1)

The microfluidic system of claim 1, wherein the detector component includes a viewing panel forming part of the first chamber to enable a user to view the surface of the plate in the first chamber.

### Claim 6 (depends on 1)

The microfluidic system of claim 1, wherein the magnet comprises an electromagnet.

### Claim 7 (depends on 1)

The microfluidic system of claim 1, wherein the control module controls the flow rate of the fluid sample to be in a range of 1 to 3 mL per minute.

### Claim 8 (depends on 1)

The microfluidic system of claim 1, further comprising the magnetic beads functionalized with one or more recognition elements.

### Claim 9 (depends on 8)

The microfluidic system of claim 8, wherein the recognition elements comprise one or more of antibodies, aptamers, low molecular weight ligands, and peptides.

### Claim 10 (depends on 9)

The microfluidic system of claim 9, wherein the antibodies comprise anti-EpCAM antibodies.

### Claim 11 (depends on 9)

The microfluidic system of claim 9, wherein the low molecular weight ligands comprise folate or 2-[3-(1,3-dicarboxy propyl)-ureido] pentanedioic acid (DUPA).

### Claim 12 (depends on 8)

The microfluidic system of claim 8, wherein the recognition elements specifically bind to tumor cells.

### Claim 13 (depends on 8)

The microfluidic system of claim 8, wherein the recognition elements specifically bind to circulating tumor cells.

### Claim 14 (depends on 12)

The microfluidic system of claim 12, wherein the tumor cells comprise cells from breast cancer, prostate cancer, lymph node carcinoma, ovarian cancer, lung cancer, renal cancer, or colon cancer.

### Claim 15 (depends on 1)

The microfluidic system of claim 1, wherein the first target entities are cells, and the second target entities are small molecules.

### Claim 16 (depends on 1)

The microfluidic system of claim 1, wherein the first target entities are a first type of cancer cells, and the second target entities are small molecules associated with the first type of cancer.

### Claim 17 (depends on 16)

The microfluidic system of claim 16, wherein the first target entities are prostate cancer cells, and the second target entities are prostate specific antigen (PSA).

### Claim 18

A microfluidic system for isolating target entities in a fluid sample containing a quantity of magnetic beads functionalized with one or more recognition elements capable of binding specifically to the target entities, the system comprising:
(a) multiple detector components each having
a body defining therein a reservoir; and
a sensor chip comprising a plate disposed within the reservoir and arranged to separate the reservoir into a first chamber with a first inlet and first outlet, and a second chamber, wherein the plate comprises a plurality of openings therethrough, wherein each opening is sized to permit passage of the magnetic beads and to prevent passage of the target entities;
(b) a magnet disposed relative to the body so that the second chambers and the plates are situated between the magnet and the first chambers;
(c) one or more pumps arranged to flow different fluid samples from multiple sources to the multiple detector components;
(d) one or more valves to connect the multiple sources to the first inlets of the first chambers of the multiple detector components; and
(e) a control module configured to
control the magnet to generate a magnetic force sufficient to pull magnetic beads in the first chambers through the openings in the plates and into the second chambers, and sufficient to attract and to hold at least some of the target entities bound to one or more magnetic beads against a surface of the plates, and
control the one or more pumps to generate a flow rate of the fluid sample sufficient to permit magnetic beads not bound to a target entity to be pulled through the plates into the second chambers, and sufficient to flow fluid sample over the plates and out of the first chambers through the first outlets without dislodging target entities bound to magnetic beads from the surface of the plates.

### Claim 19 (depends on 18)

The microfluidic system of claim 18, wherein each of the multiple sources is connected to only one of the multiple detector components.