# US 10,870,113 B1 · Isoelectric focusing devices and fixtures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,113 B1 - Document ID: US10870113B1 - Status: Granted - Kind: B1 - Application number: 16/808,063 - Filed: 2020-03-03 - Granted: 2020-12-22 - Earliest claimed: 2019-08-12 - Assignees: Intabio, Inc. - Applicants: Intabio, Inc. - Inventors: Erik Gentalen; Scott Mack; Eric Gwerder; Luc Bousse - Web page: https://patentgrep.com/patent/US10870113B1 ## CPC - B01L 3/502776: {specially adapted for focusing or laminating flows} - B01L 3/5027: {by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip} - B01L 3/502715: {characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces} - B01L 3/502723: {characterised by venting arrangements} - 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 3/502792: {for moving individual droplets on a plate, e.g. by locally altering surface tension} - G01N 27/44791: {Microapparatus (sample containers with integrated microfluidic structures B01L3/5027)} - G01N 27/44795: {Isoelectric focusing} - B01L 9/527: {for microfluidic devices, e.g. used for lab-on-a-chip} - B01L 2200/027: for microfluidic devices - B01L 2200/0636: Focussing flows, e.g. to laminate flows - B01L 2200/0647: Handling flowable solids, e.g. microscopic beads, cells, particles - B01L 2200/0684: Venting, avoiding backpressure, avoid gas bubbles - B01L 2200/16: Reagents, handling or storing thereof - B01L 2300/047: Additional chamber, reservoir - B01L 2300/0645: Electrodes - B01L 2300/0816: Cards, e.g. flat sample carriers usually with flow in two horizontal directions - B01L 2300/0864: comprising only one inlet and multiple receiving wells, e.g. for separation, splitting - B01L 2300/12: Specific details about materials - B01L 2300/161: Control and use of surface tension forces, e.g. hydrophobic, hydrophilic - B01L 2400/0421: electrophoretic flow - B01L 2400/0427: Electrowetting - 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 Methods, devices, and systems for performing isoelectric focusing reactions are described. The systems or devices disclosed herein may comprise fixtures that have a membrane. In some instances, the disclosed devices may be designed to perform isoelectric focusing or other separation reactions followed by further characterization of the separated analytes using mass spectrometry. The disclosed methods, devices, and systems provide for fast, accurate separation and characterization of protein analyte mixtures or other biological molecules by isoelectric point. ## Claims ### Claim 1 A fixture comprising: an electrode reservoir; an inlet fluid channel comprising a first end and a second end; an outlet fluid channel comprising a first end that is fluidically coupled to the second end of the inlet fluid channel, and a second end that is fluidically coupled to a separation channel, wherein the inlet fluid channel and the outlet fluid channel intersect with each other and are fluidically coupled to each other at a plane that defines or is parallel to a surface of the electrode reservoir; and a membrane disposed within the electrode reservoir, wherein the membrane is disposed at or adjacent to the plane that defines or is parallel to the surface of the electrode reservoir, wherein the membrane covers an opening of the electrode reservoir comprising the intersection of the inlet fluid channel and the outlet fluid channel; wherein the membrane provides a connection between an electrode positioned within the electrode reservoir and a fluid contained within the inlet fluid channel and outlet fluid channel; wherein the membrane comprises a first surface facing the electrode reservoir a second surface facing the intersection of the inlet fluid channel and the outlet fluid channel, wherein a hydrodynamic resistance between the first surface and the second surface is greater than 1 ((N/mm2)/(mm3/sec)) and an electrical resistance between the first surface and the second surface is less than 10,000,000 ohms; wherein the electrode reservoir further comprises an insert disposed within the electrode reservoir and positioned at or adjacent to the membrane, wherein the insert comprises an inlet fluid path arm and an outlet fluid path arm that facilitate bubble-free wetting of a surface of the membrane when the electrode reservoir is filled with a buffer solution. ### Claim 2 (depends on 1) The fixture of claim 1, wherein the membrane is hydrophilic. ### Claim 3 (depends on 1) The fixture of claim 1, wherein the membrane comprises a regenerated cellulose membrane. ### Claim 4 (depends on 1) The fixture of claim 1, wherein a cross-sectional area of the membrane or opening is between about 0.001 mm2 and 100 mm2. ### Claim 5 (depends on 1) The fixture of claim 1, wherein the separation channel comprises a lumen of a capillary. ### Claim 6 (depends on 1) The fixture of claim 1, wherein the separation channel comprises a fluid channel within a microfluidic device. ### Claim 7 (depends on 1) The fixture of claim 1, wherein the separation channel is configured to perform isoelectric focusing. ### Claim 8 A fluidic device comprising: at least one fluid inlet; at least one fluid outlet; at least one separation channel comprising, a first end that is fluidically coupled to the at least one fluid inlet and a second end that is fluidically coupled to the at least one fluid outlet; wherein at least one fluid inlet or at least one fluid outlet is electrically coupled to an electrode using a fixture comprising: an electrode reservoir; an inlet fluid channel comprising a first end and a second end; an outlet fluid channel comprising a first end that is fluidically coupled to the second end of the inlet fluid channel, and a second end that is fluidically coupled to one of the at least one fluid inlet or the at least one fluid outlet, wherein the inlet fluid channel and the outlet fluid channel intersect with each other and are fluidically coupled to each other at a plane that defines or is parallel to a surface of the electrode reservoir; and a membrane disposed within the electrode reservoir, wherein the membrane is disposed at or adjacent to the plane that defines or is parallel to the surface of the electrode reservoir, wherein the membrane covers an opening of the electrode reservoir comprising the intersection of the inlet fluid channel and the outlet fluid channel; wherein the membrane provides a connection between a electrode positioned within the electrode reservoir and a fluid contained within the inlet fluid channel and outlet fluid channel; wherein the membrane comprises a first surface facing the electrode reservoir a second surface facing the intersection of the inlet fluid channel and the outlet fluid channel, wherein a hydrodynamic resistance between the first surface and the second surface is greater than 1 ((N/mm2)/(mm3/sec)) and an electrical resistance between the first surface and the second surface is less than 10,000,000 ohms; wherein the electrode reservoir further comprises an insert disposed within the electrode reservoir and positioned at or adjacent to the membrane, wherein the insert comprises an inlet fluid path arm and an outlet fluid path arm that facilitate bubble-free wetting of a surface of the membrane when the electrode reservoir is filled with a buffer solution. ### Claim 9 (depends on 8) The device of claim 8, wherein the device comprises at least one capillary, and wherein the at least one capillary comprises a lumen which functions as the at least one separation channel. ### Claim 10 (depends on 8) The device of claim 8, wherein the device is a microfluidic device comprising a planar substrate, and wherein the planar substrate comprises the at least one separation channel. ### Claim 11 (depends on 8) The device of claim 8, wherein the membrane is hydrophilic. ### Claim 12 (depends on 8) The device of claim 8, wherein the membrane comprises a regenerated cellulose membrane. ### Claim 13 (depends on 8) The device of claim 8, wherein a cross-sectional area of the membrane or opening is between about 0.001 mm2 and 100 mm2. ### Claim 14 (depends on 8) The device of claim 8, wherein the ratio of the hydrodynamic resistance to the electrical resistance is greater than about 0.01 ((N/mm2)/(mm3/sec))/Ohm.