# US 7,608,397 B2 · Method for determining biophysical properties > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,397 B2 - Document ID: US7608397B2 - Status: Granted - Kind: B2 - Application number: 11/629,245 - Filed: 2005-06-13 - Published: 2008-03-13 - Granted: 2009-10-27 - Earliest claimed: 2004-06-11 - Assignees: Medical Biosystems, Ltd. - Inventors: Daniel Henry Densham - Web page: https://patentgrep.com/patent/US7608397B2 ## CPC - G01N 33/54373: {involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings} - B82Y 35/00: Methods or apparatus for measurement or analysis of nanostructures - G02B 5/008: {Surface plasmon devices (diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553)} - G02B 5/1809: {with pitch less than or comparable to the wavelength} - 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) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract The invention is a method for detecting a change in the conformational or energetic state of a molecular species, comprising the steps of: (i) immobilizing the molecular species, under conditions suitable for the reaction to occur; (ii) contacting at least part of the molecular species with a localized electromagnetic field; and (iii) detecting a change in dielectric constant during or after the reaction, to thereby detect a change in the conformational or energetic state of the molecular species. ## Claims ### Claim 1 A method for detecting a change in the conformational or energetic state of a molecular species during or after a reaction, comprising the steps of: (i) immobilizing the molecular species, under conditions suitable for the reaction to occur; (ii) contacting at least part of the molecular species with a localized area of electromagnetic field enhancement; and (iii) detecting a change in dielectric constant during or after the reaction, to thereby detect a change in the conformational or energetic state of the molecular species. ### Claim 2 (depends on 1) The method according to claim 1, wherein the molecular species is immobilized to a solid support. ### Claim 3 (depends on 1) The method according to claim 1, wherein the molecular species is a protein. ### Claim 4 (depends on 1) The method according to claim 1, wherein the molecular species is a polynucleotide processive enzyme. ### Claim 5 (depends on 4) The method according to claim 4, wherein a conformational change results from the interaction of the enzyme with a target polynucleotide. ### Claim 6 (depends on 4) The method according to claim 4, wherein the enzyme is a polymerase. ### Claim 7 (depends on 6) The method according to claim 6, wherein incorporation of each of the nucleotides A, T (U), G and C causes a characteristic change in the energetic state/conformation of the polymerase. ### Claim 8 (depends on 1) The method according to claim 1, wherein the localized area of electromagnetic field enhancement is created by positioning the molecular species between first and second electrodes and applying an electrical signal to the first electrode. ### Claim 9 (depends on 8) The method according to claim 8, wherein the first and second electrodes are spaced between 1 nm and 1mm apart. ### Claim 10 (depends on 8) The method according to claim 8, wherein the electrical signal is an AC voltage of predetermined frequency. ### Claim 11 (depends on 10) The method according to claim 10, wherein the frequency is between 1 Hz and 100 GHz. ### Claim 12 (depends on 8) The method according to claim 8, wherein a change in the conformational or energy state of the molecular species is detected by measuring a change in the impedance of the electrodes. ### Claim 13 (depends on 8) The method according to claim 8, wherein a change in the conformational or energy state of the molecular species is detected by measuring a change in the total capacitance of the electrodes. ### Claim 14 (depends on 13) The method according to claim 13, wherein the capacitance is measured using an AC bridge. ### Claim 15 (depends on 1) The method according to claim 1, wherein the localized area of electromagnetic field enhancement is created by an integrated plasmon wave concentrator, microfabricated on a metal layer capable of supporting surface plasmons. ### Claim 16 (depends on 15) The method according to claim 15, wherein the plasmon wave concentrator comprises a sub-wavelength aperture surrounded by at least one linear groove, with dielectric layers above and below. ### Claim 17 (depends on 16) The method according to claim 16, wherein the at least one linear groove is situated on both the upper and reverse sides of the metal layer. ### Claim 18 (depends on 16) The method according to claim 16, wherein a change in the conformational or energy state of the molecular species is detected by creating a visible or infra-red laser incident to the metal layer(s) and measuring a change in the intensity of the light emitted from the sub-wavelength aperature. ### Claim 19 (depends on 16) The method according to claim 16, wherein a change in the conformational or energy state of the molecular species is detected by creating a visible or infra-red laser incident to the metal layer(s) and measuring the phase shift of light emitted from the sub-wavelength aperture as it passes through a concentrator structure. ### Claim 20 (depends on 16) The method according to claim 16, wherein a change in the conformational or energy state of the molecular species is detected by creating a broad-band electromagnetic beam incident to the metal layer(s) and measuring a change in the wavelength of light emitted from the sub-wavelength aperature. ### Claim 21 (depends on 1) The method according to claim 1, wherein the localized area of electromagnetic field enhancement is created by a metalized scanning probe microscope or atomic force microscope tip, on a surface plasmon supporting surface.