# US 8,771,938 B2 · Microfluidic platforms for multi-target detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,938 B2 - Document ID: US8771938B2 - Status: Granted - Kind: B2 - Application number: 12/246,987 - Filed: 2008-10-07 - Published: 2009-04-09 - Granted: 2014-07-08 - Earliest claimed: 2007-10-09 - Assignees: University of Notre Dame du Lac - Applicants: Hsueh-Chia Chang; Jason Gordon; Satyajyoti Senpati; Zachary Gagnon; Sagnik Basuray - Inventors: Hsueh-Chia Chang; Jason Gordon; Satyajyoti Senpati; Zachary Gagnon; Sagnik Basuray - Web page: https://patentgrep.com/patent/US8771938B2 ## CPC - B03C 5/005: {Dielectrophoresis, i.e. dielectric particles migrating towards the region of highest field strength} - B03C 5/026: {using open-gradient differential dielectric separation, i.e. using electrodes of special shapes for non-uniform field creation, e.g. Fluid Integrated Circuit [FIC]} - C12Q 1/6816: characterised by the detection means (C12Q1/6804 takes precedence) - B01J 2219/00459: Beads - B01J 2219/005: Beads - B01J 2219/00511: Walls of reactor vessels - B01J 2219/00596: Solid-phase processes - B01J 2219/00605: the compounds being directly bound or immobilised to solid supports - B01J 2219/00612: the surface being inorganic - 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} - B03C 2201/26: for use in medical or biological applications - G01N 21/64: Fluorescence; Phosphorescence - B03C: MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS (separating isotopes B01D59/00; combinations of magnetic or electrostatic separation with separation of solids by other means B03B, B07B) - 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 - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - 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 Disclosed are example methods and devices for detecting one or more targets. An example method includes placing a sample including a first target with in a microfluidic device and hybridizing a plurality of copies of the first target with a plurality of nanostructures. The example method includes applying an electric current to the plurality of nanostructures and using an electric field created by the electric current to move the plurality of nanostructures. In addition, the plurality of nanostructures are sorted and evaluated to determine at least one of a presence, an absence, or a quantity of the first target. ## Claims ### Claim 1 A method of detecting a plurality of target nucleic acids, the method comprising: continuously flowing a sample solution comprising the target nucleic acids through a microfluidic device having at least a first surface with a first electrode and a second surface displaced from the first surface at a distance and having a second electrode opposing the first electrode; provided a first and second functionalized nanostructure in solution to the microfluidic device, wherein the first nanostructure is formed by functionalizing a first probe complementary to a first target nucleic acid and the second nanostructure is formed by functionalizing a second probe complementary to a second target nucleic acid; applying an electric current to the electrodes; using the electric field created by the electric current applied to the electrodes to move the nanostructures; trapping the nanostructures within the electric field; mixing the sample solution and the solution providing the nanostructure; hybridizing the target nucleic acids with the nanostructures in the presence of the electric field; hydrodynamically shearing at least one of a non-target or a weakly hybridized target nucleic acid from the nanostructures, wherein the application of the electric current to the nanostructures causes the nanostructure hybridized with the first target to move in a first direction and causes the nanostructure hybridized with the second target to move in a second direction, and wherein the first target and the second target are sorted based on the first direction or the second direction; and evaluating the trapped nanostructures by measuring an electrical impedance between the electrodes to determine a presence, an absence, or a quantity of the first or second target nucleic acids. ### Claim 2 (depends on 1) A method as defined in claim 1, wherein the electric current induces dielectrophoresis. ### Claim 3 (depends on 1) A method as defined in claim 1, wherein a presence of an increased pressure does not impede the method. ### Claim 4 (depends on 1) A method as defined in claim 1, wherein a copy of at least one of the plurality of target nucleic acids is produced via a polymerase chain reaction. ### Claim 5 (depends on 1) A method as defined in claim 1, wherein the electric field has at least a first frequency and a second frequency, and wherein the nanostructures move in a first direction at the first frequency and in a second direction at the second frequency. ### Claim 6 (depends on 1) A method as defined in claim 1, wherein the plurality of nanostructures form a pattern dependent on a frequency of the electric field. ### Claim 7 (depends on 1) A method as defined in claim 1, wherein the electric current creates a non-uniform electric field across the microfluidic device. ### Claim 8 (depends on 1) A method as defined in claim 1, wherein the nanostructures are one or more of carbon nanotubes, nanobeads, nanowires, nanocolloides, nanoparticles, nanorods, quantum dots, nanocrystals, liposomes, silica beads, latex beads, gold colloids or other structures with dimensions less than one micron. ### Claim 9 (depends on 1) A method as defined in claim 1, wherein the one or more of the first or second probes includes one or more of a oligomer, a fluorophore, a carboxyl group, or a streptavidin. ### Claim 10 (depends on 1) A method as defined in claim 1 further comprising pretreating the sample. ### Claim 11 (depends on 10) A method as defined in claim 10, wherein pretreating includes at least one of filtering or removal of inhibitors. ### Claim 12 A method of detecting a target nucleic acid, the method comprising: obtaining a sample including the target nucleic acid; functionalizing a first molecular probe complementary to a first target nucleic acid to a first nanostructure and functionalizing a second molecular probe complementary to a second target nucleic acid to a second nanostructure; coupling the functionalized nanostructures to a chamber having a first surface with a first electrode and a second surface displaced from the first surface at a distance and having a second electrode opposing the first electrode; flowing the target nucleic acids through the chamber to hybridize the first target nucleic acid to the first functionalized nanostructure and to hybridize the second target nucleic acid to the second functionalized nanostructure; causing the nanostructure hybridized with the first target to move in a first direction and causing the nanostructure hybridized with the second target to move in a second direction, wherein the first target and the second target are sorted based on the first direction or the second direction; and detecting at least one of a presence, an absence, or a quantity of the first or second target nucleic acids by measuring an electrical impedance between the electrodes. ### Claim 13 (depends on 12) A method as defined in claim 12, wherein at least one of the first or second target nucleic acids is replicated through a polymerase chain reaction and flowing the amplified mixture through the chamber. ### Claim 14 (depends on 13) A method as defined in claim 13, wherein the polymerase chain reaction uses two differently labeled primers. ### Claim 15 (depends on 14) A method as defined in claim 14, wherein one of the primers is biotinylated and the other is fluorescently labeled. ### Claim 16 (depends on 12) A method as defined in claim 12 further comprising applying an alternating current electric field to the chamber wherein the presence of the electric field improves hybridization rate and yield. ### Claim 17 A method of detecting target nucleic acids comprising: placing a solution having a plurality of functionalized nanostructures within a channel having a first surface with a first electrode and a second surface displaced from the first surface at a distance and having a second electrode opposing the first electrode, wherein a first one of the plurality of functionalized nanostructures includes a oligonucleotide probe complementary to a first target nucleic acid and wherein a second one of the plurality of functionalized nanostructures includes a oligonucleotide probe complementary to a second target nucleic acid; applying an alternating current field to the first and second electrodes to focus and trap the nanostructures; flowing a sample including the target nucleic acids within the channel and through the trapped functionalized nanostructures; hybridizing the target nucleic acids with at least one of the nanostructures; hydrodynamically shearing at least one of a non-target or a weakly hybridized target nucleic acid from the nanostructures, wherein the application of the electric current to the nanostructures causes the nanostructure hybridized with the first target to move in a first direction and causes the nanostructure hybridized with the second target to move in a second direction, and wherein the first target and the second target are sorted based on the first direction or the second direction; and evaluating the trapped nanostructures by measuring an impedance signal during the sample flow to determine a presence, an absence, or a quantity of the target nucleic acids. ### Claim 18 (depends on 17) A method as defined in claim 17, wherein the applied electric field is an alternating current field with a period shorter than the Faradaic reaction time corresponding to the respective voltage. ### Claim 19 (depends on 18) A method as defined in claim 18, wherein the alternating current applied to the first and second electrodes creating the electric field is also used to provide the measurement of electrical impedance between the electrodes. ### Claim 20 (depends on 17) A method as defined in claim 17, wherein the nanostructures are carbon nanotubes. ### Claim 21 (depends on 20) A method as defined in claim 20, wherein the carbon nanotubes trapped at the electrodes focus the electric field thereby concentrating targets between the first and second electrodes. ### Claim 22 (depends on 21) A method as defined in claim 21, wherein the carbon nanotubes enhance dielectropheretic forces within the channel. ### Claim 23 (depends on 17) A method as defined in claim 17, wherein hybridization yield and rate are enhanced in the presences of an electric field. ### Claim 24 (depends on 17) A method as defined in claim 17, wherein the nanostructures are trapped by force induced by dielectrophoresis. ### Claim 25 (depends on 17) A method as defined in claim 17, wherein the nanostructures are evaluated based on a change in impedance signal before and after hybridization with the target nucleic acids with the shift in impedance relevant to the number of hybridized targets.