title: β-D-glucosidase assisted gold dissolution as non-optical and quantifiable detection technique for immunoassays.
abstract: Immunoassays are used for detecting protein targets for various applications. Here, a modification of immunoassays to allow a purely electrical detection of the target protein concentration is shown. The modification comprises a β-D-glucosidase as reporter enzyme and a cyanogenic glycoside as substrate. The enzymatic reaction produces cyanide in small quantities. For electrical detection of the cyanide, a novel sensor is developed, based on a gold micro wire. The cyanide dissolves the gold wire and changes the electrical resistance of the wire. Monitoring the resistance change allows a quantitative measurement of the target human C-reactive protein (an inflammatory marker) in blood plasma in the physiological relevant concentration range.
authors.affiliation: Institute of Chemical- and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland, Fax: (+) 41 44 633 15 71.
authors.forename: F M
authors.initials: FM
authors.lastname: Koehler
authors.forename: R A
authors.initials: RA
authors.lastname: Raso
authors.forename: R N
authors.initials: RN
authors.lastname: Grass
authors.forename: W J
authors.initials: WJ
authors.lastname: Stark
mesh_terms: D002097:C-Reactive Protein / Q000032:analysis; D005959:Glucosidases / Q000737:chemistry* / Q000378:metabolism*; D006027:Glycosides / Q000378:metabolism; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods*
chemical_list: D006027:Glycosides; C007173:cyanogenic glycosides; D006046:Gold; D002097:C-Reactive Protein; D005959:Glucosidases
keywords: cyanide sensors; gold wires; immunosoassays; point of care; rapid diagnostics