# US 12,766,510 B2 · Microfluidic device for and methods of using surface-attached posts and capture beads in a microfluidic chamber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,766,510 B2 - Document ID: US12766510B2 - Status: Granted - Kind: B2 - Application number: 17/776,797 - Filed: 2020-11-16 - Published: 2022-12-15 - Granted: 2026-10-20 - Earliest claimed: 2019-11-15 - Assignees: Redbud Labs, Inc. - Applicants: Redbud Labs, Inc. - Inventors: Richard Chasen Spero; Jay Kenneth Fisher; Dale Barnes; Olivia Kanies - Web page: https://patentgrep.com/patent/US12766510B2 ## 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 2200/0668: Trapping microscopic beads - B01L 2300/0877: Flow chambers - B01L 2300/123: Flexible; Elastomeric - B01L 2400/043: magnetic forces - B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE ## Abstract A microfluidic device for and methods of using surface-attached posts and capture beads in a microfluidic chamber is disclosed. For example, the microfluidics device includes a pair of substrates separated by a gap and thereby forming a reaction (or assay) chamber therebetween. A field of actuatable surface-attached posts (e.g., magnetically responsive microposts) is provided on one or both of the substrates. The surface-attached posts are functionalized with capture beads. Additionally, methods are provided of functionalizing the surface-attached posts with the capture beads. Additionally, methods are provided of using the surface-attached posts that are functionalized with capture beads in a microfluidics device for binding a target of interest. Further, a bead spraying system and method is provided for spraying magnetically responsive and/or non-magnetically responsive beads atop and/or among a field of surface-attached microposts for use in a microfluidic device. ## Claims ### Claim 1 A microfluidic cartridge comprising: a. a housing forming a reaction chamber; b. a field of actuatable surface-attached microposts provided on an interior surface of the housing and extending into the reaction chamber, wherein the actuatable surface-attached microposts are configured to move when actuated; and c. beads attached to the microposts; and wherein the beads comprise a core that is covered by a polymer shell and the polymer shell provides a surface for a subsequent functionalization reaction or reactions, and the core further comprises a magnetically-responsive material. ### Claim 2 (depends on 1) The microfluidic cartridge of claim 1, wherein the reaction chamber further comprises openings arranged for flowing fluid into and out of the chamber. ### Claim 3 (depends on 1) The microfluidic cartridge of claim 1, wherein the housing comprises two substrates separated to form the reaction chamber as a gap between the substrates. ### Claim 4 (depends on 1) The microfluidic cartridge of claim 1, wherein the beads are functionalized. ### Claim 5 (depends on 1) The microfluidic cartridge of claim 1, wherein the actuatable surface-attached microposts comprise magnetically-responsive microposts that can be actuated and moved using a magnetic actuation mechanism. ### Claim 6 (depends on 1) The microfluidic cartridge of claim 1, wherein the beads comprise target-specific beads, wherein the target-specific beads are pre-functionalized with a binding agent that is specific for one or more targets of interest, the pre-functionalized beads are bound to the actuatable urface-attached microposts using a functional group linker or using a lyophilization process or via non-specific adsorption of the beads to the microposts, and the microposts are maintained in an upright orientation by the lyophilization process. ### Claim 7 (depends on 1) The microfluidic cartridge of claim 1, wherein a chemical bonding reaction is used to adhere a magnetically-responsive bead to the surface of a micropost, and wherein the chemical bonding reaction is selected from the group consisting of an avidin/biotin complexation interaction or a carboxy group/amine linkage. ### Claim 8 (depends on 1) The microfluidic cartridge of claim 1, wherein a remnant (latent) magnetic field is generated in the actuatable surface-attached microposts, thereby attracting and binding the beads to the microposts via magnetism. ### Claim 9 (depends on 1) The microfluidic cartridge of claim 1, wherein the beads are bound to at least one substrate surface of the reaction chamber by an ambient magnetic field. ### Claim 10 (depends on 1) The microfluidics cartridge of claim 1, wherein the polymer shell is selected from the group consisting of a polystyrene or a silica-based material. ### Claim 11 (depends on 1) An instrument comprising: a. an actuation mechanism, and b. the microfluidic cartridge of claim 1, wherein the actuation mechanism generates an actuation force thereby compelling at least a portion of the actuatable surface-attached microposts to move, and wherein the actuation force is selected from the group consisting of a magnetic, thermal, sonic, and/or electric force. ### Claim 12 (depends on 11) The instrument of claim 11, wherein the actuatable surface-attached microposts are functionalized with the beads for specific binding of one or more targets of interest. ### Claim 13 (depends on 11) The instrument of claim 11, wherein the microposts are pre-magnetized to create a magnetic field in the microposts and then magnetically-responsive beads are bound to the microposts, whereby the beads provide a surface for binding one or more targets of interest, and wherein the beads comprise a superparamagnetic material. ### Claim 14 (depends on 11) The instrument of claim 11, wherein the bead is pre-coupled with a ligand, and wherein the ligand is selected from the group consisting of an antibody, a protein, an antigen, a DNA/RNA probe, or any other molecule with an affinity for one or more targets of interest. ### Claim 15 (depends on 11) A method of capturing a target, the method comprising: a. providing the instrument of claim 11; b. causing a sample comprising the target to flow through the reaction chamber; and c. causing the actuation mechanism to generate an actuation force thereby compelling at least a portion of the actuatable surface-attached microposts to move, thereby causing the target to bind to the beads. ### Claim 16 (depends on 15) The method of claim 15, further comprising: a. causing a wash buffer to flow through the reaction chamber; and b. causing the actuation mechanism to generate an actuation force thereby compelling at least a portion of the actuatable surface-attached microposts to move, thereby washing the beads. ### Claim 17 (depends on 15) The method of claim 15, further comprising: a. causing an elution buffer to flow through the reaction chamber; and b. causing the actuation mechanism to generate an actuation force thereby compelling at least a portion of the actuatable surface-attached microposts to move, thereby eluting the target from the beads.