Claims for Patent: 8,092,670

Summary for Patent: 8,092,670

Title:	Method for specifically detecting analyte using photocurrent, and electrode, measuring cell and measuring device for use therein
Abstract:	A method, an electrode, a measuring cell, and a measuring device are disclosed which can detect and quantitatively determine an analyte having specific bonding properties, in a highly sensitive, simple and accurate manner using photocurrent. This method comprises contacting a working electrode and a counter electrode with an electrolyte medium, wherein the working electrode has an analyte immobilized thereon through a probe substance and wherein the analyte is bonded to a sensitizing dye; irradiating the working electrode with light to photoexcite the sensitizing dye; and detecting photocurrent flowing between the working electrode and the counter electrode, wherein the photocurrent is generated by transfer of electrons from the photoexcited sensitizing dye to the working electrode. The working electrode comprises an electron accepting layer comprising an electron accepting substance capable of accepting electrons released from the sensitizing dye in response to photoexcitation, wherein the probe substance is supported on a surface of the electron accepting layer. The electron accepting substance is an oxide semiconductor having an energy level lower than that of a lowest unoccupied molecular orbit (LUMO) of the sensitizing dye. The electrolyte medium comprises an electrolyte and at least one solvent selected from an aprotic solvent and a protic solvent, wherein the electrolyte comprises a salt capable of providing an oxidized sensitizing dye with electrons.
Inventor(s):	Bekki; Makoto (Kitakyushu, JP), Ohara; Hitoshi (Kitakyushu, JP), Sonezaki; Shuji (Kitakyushu, JP), Kanehira; Koki (Kitakyushu, JP), Ogami; Yumi (Yukuhashi, JP), Ishikawa; Hiroshi (Kitakyushu, JP), Osaki; Yumi (Suita, JP), Tokudome; Hiromasa (Chigasaki, JP), Yamada; Yoko (Chigasaki, JP), Miyauchi; Masahiro (Fujisawa, JP)
Assignee:	Toto Ltd. (Fukuoka-ken, JP)
Application Number:	11/992,858
Patent Claims:	1. A method for specifically detecting an analyte, comprising the steps of: contacting a working electrode and a counter electrode with an electrolyte medium, the working electrode having an analyte immobilized thereon through a probe substance, the analyte being bonded to a sensitizing dye; irradiating the working electrode with light to photoexcite the sensitizing dye; and detecting photocurrent flowing between the working electrode and the counter electrode, the photocurrent being generated by transfer of electrons from the photoexcited sensitizing dye to the working electrode; wherein the working electrode comprises an electron accepting layer comprising an electron accepting substance capable of accepting electrons released from the sensitizing dye in response to photoexcitation, the probe substance being supported on a surface of the electron accepting layer; wherein the electron accepting substance is an oxide semiconductor having an energy level lower than that of a lowest unoccupied molecular orbit (LUMO) of the sensitizing dye; wherein the electrolyte medium comprises an electrolyte and at least one solvent selected from an aprotic solvent and a protic solvent, the electrolyte comprising a salt capable of providing an oxidized sensitizing dye with electrons; and wherein the electrolyte is at least one selected from the group consisting of tetraalkylammonium iodide, Br.sub.2-free bromide, thiosulfate, and sulfite. 2. A method according to claim 1, wherein the electrolyte medium has a reduction potential of higher than an energy level of a highest occupied molecular orbit (HOMO) of the sensitizing dye and lower than an energy level of a conduction band of the electron accepting substance. 3. A method according to claim 1, wherein the electrolyte is tetraalkylammonium iodide. 4. A method according to claim 1, wherein the electrolyte is at least one selected from the group consisting of thiosulfate and sulfite. 5. A method according to claim 4, wherein the electrolyte is thiosulfate; and the thiosulfate is sodium thiosulfate. 6. A method according to claim 4, wherein the electrolyte is sulfite and wherein the sulfite is sodium sulfite. 7. A method according to claim 1, wherein the solvent is an aprotic solvent. 8. A method according to claim 7, wherein the aprotic solvent is acetonitrile (CH.sub.3CN). 9. A method according to claim 1, wherein the solvent is a protic solvent. 10. A method according to claim 9, wherein the protic solvent is water. 11. A method according to claim 1, wherein the solvent is a mixture of an aprotic solvent and a protic solvent. 12. A method according to claim 1, wherein the electron accepting layer has a cationized surface. 13. A method according to claim 1, wherein a solution comprising the probe substance is brought into contact with the working electrode to make the probe substance supported on the electron accepting layer. 14. A method according to claim 1, further comprising the step of cleaning the working electrode with a cleaning fluid before contacting the working electrode and the counter electrode with the electrolyte medium. 15. A method according to claim 1, wherein the analyte is labeled with the sensitizing dye in advance. 16. A method according to claim 1, wherein the analyte is a single-stranded nucleic acid; and wherein the probe substance is a single-stranded nucleic acid having complementarity to the nucleic acid of the analyte. 17. A method according to claim 16, wherein the nucleic acid having the complementarity comprises a complementary portion which is 15bp longer than the nucleic acid. 18. A method according to claim 16, wherein the analyte is a nucleic acid labeled with the sensitizing dye in advance and wherein each molecule of the analyte is labeled with one or more of the sensitizing-dye. 19. A method according to claim 1, wherein the analyte is bonded to the probe substance by bringing a sample liquid comprising the analyte into contact with the working electrode under coexistence of the sensitizing dye; wherein the sample liquid further comprises a mediator substance capable of specifically bonding to the analyte, the mediator substance being labeled with the sensitizing dye in advance; and wherein a conjugate of the mediator substance and the analyte specifically bonds to the probe substance. 20. A method according to claim 19, wherein the analyte is a ligand, wherein the mediator substance is a receptor protein molecule and wherein the probe substance is a double-stranded nucleic acid. 21. A method according to claim 19, wherein the analyte is an endocrine disruptor. 22. A method according to claim 1, wherein the step of detecting the photocurrent comprises measuring an electric current value or an electrical quantity; and calculating concentration of the analyte in the sample liquid from the electric current value or electrical quantity thus measured. 23. A method according to claim 22, wherein the step of calculating concentration of the analyte in the sample liquid from the measured electric current value or electrical quantity is carried out by applying the measured electric current value or electric quantity to a pre-created calibration line of analyte concentration versus electric current value or electric quantity. 24. A method according to claim 22, wherein the analyte is bonded to the probe substance by bringing the sample liquid comprising the analyte into contact with the working electrode under coexistence of the sensitizing dye; wherein the sample liquid further comprises a second analyte capable of specifically bonding to the probe substance, the second analyte not being labeled with the sensitizing dye, so that the analyte and the second analyte compete to specifically bond to the probe substance; wherein the step of detecting the photocurrent comprises measuring an electric current value or an electrical quantity; and calculating concentration of the second analyte in the sample liquid from the measured electric current value or electrical quantity. 25. A method according to claim 24, wherein the step of calculating concentration of the second analyte in the sample liquid from the measured electric current value or electrical quantity is carried out by applying the measured electric current value or electric quantity to a pre-created calibration line of second-analyte concentration versus electric current value or electric quantity. 26. A method according to claim 24, wherein the analyte and the second analyte are an antigen and wherein the probe substance is an antibody. 27. A method according to claim 24, wherein the second analyte has greater tendency to bond specifically to the probe substance than the analyte. 28. A method according to claim 1, wherein the electron accepting substance comprises at least one selected from the group consisting of titanium oxide, zinc oxide, tin oxide, niobium oxide, indium oxide, tungsten oxide, tantalum oxide, and strontium titanate. 29. A method according to claim 28, wherein the electron accepting substance is titanium oxide or strontium titanate. 30. A method according to claim 28, wherein the electron accepting substance is either indium-tin composite oxide (ITO) or fluorine-doped tin oxide (FTO). 31. A method according to claim 1, wherein the working electrode further comprises an conductive substrate; and wherein the electron accepting layer is formed on the conductive substrate. 32. A method according to claim 1, wherein the sensitizing dye is a metal complex dye or an organic dye. 33. A method according to claim 32, wherein the sensitizing dye is at least one selected from the group consisting of metal phthalocyanines; chlorophyll and its derivatives; complexes of hemin, ruthenium, osmium, iron and zinc; metal-free phthalocyanine, 9-phenylxanthene dye, cyanine dye, metallocyanine dye, xanthene dye, triphenylmethane dye, acridine dye, oxazine dye, coumarin dye, merocyanine dye, rhodacyanine dye, polymethine dye, and indigo dye. 34. A method according to claim 32, wherein the sensitizing dye is at least one selected from the group consisting of Cy3, Cy5, Cy5.5, Cy7, Cy7.5, Cy9, FAM, FITC, HEX, Rhodamine, Rhodamine-green, ROX, TET, TEXAS RED, Beckman Dyes2, Beckman Dyes3, Beckman Dyes 4, fluorescein and Alexa Fluor dye. 35. A method according to claim 1, wherein there are two or more kinds of the analytes; wherein the analytes are respectively labeled with different sensitizing dyes capable of being excited with lights of different wavelengths from each other; and wherein each sensitizing dye is irradiated with the light of a different wavelength to detect each of the analytes individually. 36. A method according to claim 1, wherein the probe substance is supported on each of a plurality of regions isolated from each other on the working substrate; and wherein each region is individually irradiated with light. 37. A method according to claim 36, wherein the electron accepting layer is formed over the entire surface of the conductive substrate; and wherein photocurrent flowing through the conductive substrate as a whole is detected. 38. A method according to claim 36, wherein a plurality of kinds of the probe substances are supported on each of the plurality of regions isolated from each other on the working electrode, so that a plurality of sample liquids are measured simultaneously. 39. A method according to claim 36, wherein the probe substance is supported on each of the plurality of regions isolated from each other on the working electrode, the probe substance being different from region to region, so that a plurality of kinds of analytes are measured simultaneously. 40. A method according to claim 1, wherein the working electrode further comprises an insulating substrate; wherein spots comprising the conductive substrate and the electron accepting layer are formed on the insulating substrate, each of the spots being disposed in each of a plurality of regions isolated from each other; and wherein photocurrent flowing through the conductive substrate in each of the regions is individually detected. 41. A method according to claim 1, wherein the working electrode further comprises an insulating substrate; wherein spots comprising the electron accepting layer are separately formed on the insulating substrate, each of the spots being disposed in each of a plurality of regions isolated from each other; and wherein photocurrent flowing through the electron accepting layer in each of the regions is individually detected. 42. A method according to claim 1, wherein the light is substantially free from ultraviolet ray. 43. A method according to claim 42, wherein the light is emitted from at least one light source selected from the group consisting of a laser, an inorganic electroluminescence (EL) device, an organic electroluminescence (EL) device and a light-emitting diode (LED). 44. A method according to claim 1, wherein the light irradiation is carried out through means for removing ultraviolet ray. 45. A method according to claim 44, wherein the means for removing the ultraviolet ray is an optical filter or a spectroscope.

Details for Patent 8,092,670

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Recordati Rare Diseases, Inc.	PANHEMATIN	hemin for injection	For Injection	101246	07/20/1983		2025-09-29