# US 10,501,789 B2 · Microfluidic process for treating and analysing a solution containing a biological material and corresponding microfluidic circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,789 B2 - Document ID: US10501789B2 - Status: Granted - Kind: B2 - Application number: 15/787,457 - Filed: 2017-10-18 - Published: 2018-02-08 - Granted: 2019-12-10 - Earliest claimed: 2012-10-08 - Assignees: Ecole Polytechnique; Centre National De La Recherche Scientifique - Applicants: Ecole Polytechnique; Centre National De La Recherche Scientifique - Inventors: Charles Baroud; Remi Dangla; Paul Abbyad; Silvan Turkcan - Web page: https://patentgrep.com/patent/US10501789B2 ## CPC - C12Q 1/686: Polymerase chain reaction [PCR] - B01L 3/50273: {characterised by the means or forces applied to move the fluids} - 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 3/502784: {specially adapted for droplet or plug flow, e.g. digital microfluidics} - B01L 3/502792: {for moving individual droplets on a plate, e.g. by locally altering surface tension} - B01L 7/52: {with provision for submitting samples to a predetermined sequence of different temperatures, e.g. for treating nucleic acid samples} - B01L 2200/0642: Filling fluids into wells by specific techniques - B01L 2200/0652: Sorting or classification of particles or molecules - B01L 2200/0668: Trapping microscopic beads - 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 2300/0867: Multiple inlets and one sample wells, e.g. mixing, dilution - B01L 2400/0457: passive flow or gravitation - B01L 2400/0463: Hydrodynamic forces, venturi nozzles - B01L 2400/084: Passive control of flow resistance - C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES - B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE ## Abstract The subject matter of the present invention is a microfluidic process for treating and analysing a solution containing a biological material, comprising a step of introducing the solution into microchannels of a microfluidic circuit (1), a step of forming drops of this solution, under the effect of modifications of the surface tension of the solution, a step of moving the drops to one or more drop storage zones(s) (130), under the effect of modifications of the surface tension of the drops, a step of treating the drops and a step of analysing the drops. ## Claims ### Claim 1 A microfluidic process for partitioning a solution, said microfluidic process comprising the steps of: a. providing a microfluidic circuit, wherein microchannels suitable for containing fluids are defined, said circuit comprising at least one device for forming a plurality of droplets of a solution in a carrier fluid, and at least one storage zone, wherein: said at least one device for forming droplets further comprises said microchannels, wherein each of said microchannels comprise wall portions that diverge to detach a droplet of said solution under the effect of surface tension of said solution, said at least one storage zone comprises a rectangular-shaped step on at least one of its bounds, said at least one device for forming droplets opens onto said rectangular-shaped step of said at least one storage zone, and said at least one storage zone is a zone where the plurality of droplets is held after formation in the microfluidic circuit but cannot come out without external intervention, regardless of the carrier fluid flow; b. filling the microfluidic circuit with the carrier fluid; and c. flowing the solution in the carrier fluid through the microchannels of the microfluidic circuit, thereby generating a plurality of droplets of said solution. ### Claim 2 (depends on 1) The microfluidic process according to claim 1, wherein the microfluidic process further comprises: d. moving at least a portion of the plurality of droplets to the at least one storage zone in the microfluidic circuit, thereby concentrating the at least a portion of the plurality of droplets in said at least one storage zone. ### Claim 3 (depends on 1) The microfluidic process according to claim 1, wherein the at least one storage zone is a zone wherein the droplets have a lower surface energy than in the adjacent zones. ### Claim 4 (depends on 1) The microfluidic process according to claim 1, wherein the carrier fluid is substantially static. ### Claim 5 (depends on 2) A microfluidic process for analyzing a solution comprising at least one biological material, wherein said process comprises the steps of: a. generating a plurality of droplets of said solution by partitioning the solution according to the microfluidic process of claim 2; c. analyzing the plurality of droplets located in the at least one storage zone. ### Claim 6 (depends on 5) The microfluidic process according to claim 5, wherein the at least one storage zone comprises, at least in part, a transparent material suitable for analyzing the plurality of droplets located in said at least one storage zone, from outside the microfluidic circuit. ### Claim 7 (depends on 5) The microfluidic process according to claim 5, wherein analyzing the plurality of droplets is performed by fluorescence analysis, optical absorption analysis, colorimetric analysis or luminescence analysis. ### Claim 8 (depends on 5) The microfluidic process according to claim 5, wherein the at least one biological material is selected from the group consisting of a polynucleotide, a chromosome, a cell, a protein, a peptide and combinations thereof. ### Claim 9 (depends on 5) The microfluidic process according to claim 5, wherein each droplet of the plurality of droplets comprises, at most, a single biological material. ### Claim 10 (depends on 5) The microfluidic process according to claim 5, wherein the solution further comprises at least one reagent selected from group consisting of an enzyme, a protein, a polynucleotide, a buffer, a small molecule, a dye and combinations thereof. ### Claim 11 (depends on 5) The microfluidic process according to claim 5, wherein the process further comprises: b. applying at least one treatment to the plurality of droplets located in the storage zone. ### Claim 12 (depends on 11) The microfluidic process according to claim 11, wherein the at least one treatment is selected from the group consisting of thermal treatment, biological treatment, chemical treatment, magnetic treatment, electrical treatment and light treatment. ### Claim 13 (depends on 11) The microfluidic process according to claim 11, wherein the at least one treatment is a polymerase chain reaction (PCR) amplification. ### Claim 14 (depends on 13) The microfluidic process according to claim 13, wherein the PCR amplification is a digital polymerase chain reaction amplification (dPCR) or a reverse-transcription digital polymerase chain reaction amplification (RT-dPCR). ### Claim 15 (depends on 2) A microfluidic process for detecting at least one nucleic acid target in a solution comprising at least one biological sample, wherein said process comprises the steps of: a. generating a plurality of droplets of said solution by partitioning the solution according to the microfluidic process of claim 2, wherein each droplet of the plurality of droplets comprises, at most, a single nucleic acid template and a mixture of at least one group of primer pairs or probes specific for the at least one nucleic acid target on the template, b. amplifying the nucleic acid template in the plurality of droplets, and c. analyzing the plurality of droplets located in the at least one storage zone. ### Claim 16 (depends on 15) The microfluidic process according to claim 15, wherein at least a portion of the plurality of droplets does not comprise any nucleic acid template. ### Claim 17 (depends on 15) The microfluidic process according to claim 15, wherein each at least one group of primer pairs or probes each comprise at least one detectable label. ### Claim 18 (depends on 15) The microfluidic process according to claim 15, wherein the process is for detecting a plurality of nucleic acid targets in a solution, each droplet of the plurality of droplets comprises, at most, a single nucleic acid template and a heterogenous mixture of primer pairs and probes, each specific for multiple target sites on the template, and each group of primer pairs and probes in heterogenous mixture comprise a different detectable label. ### Claim 19 (depends on 2) A microfluidic process for single-cell gene expression analysis, wherein said process comprises the steps of: a. generating a plurality of droplets of said solution by partitioning the solution according to the microfluidic process of claim 2, wherein each droplet of the plurality of droplets comprises, at most, a single cell and a mixture of at least one group of primer pairs or probes specific for the at least one mRNA sequence template, b. lysing the single cell in the plurality of droplets, thereby releasing mRNAs, c. reverse-transcribing the released mRNA sequence template in the plurality of droplets, and d. analyzing the plurality of droplets located in the at least one storage zone. ### Claim 20 (depends on 19) The microfluidic process according to claim 19, wherein at least a portion of the plurality of droplets does not comprise any cell.