title: Reagentless biosensors based on co-entrapment of a soluble redox polymer and an enzyme within an electrochemically deposited polymer film.
abstract: A novel biosensor architecture, which is based on the combination of a manual and a non-manual deposition technique for sensor components on the electrode surface is reported. A water-soluble Os-poly(vinyl-imidazole) redox hydrogel is deposited on a graphite electrode by drop-coating (i.e. manually) followed by the electrochemically-induced deposition of an enzyme-containing non-conducting polymer film. The local polymer deposition is initiated by electrochemical generation of H(3)O(+) exclusively at the electrode surface causing a pH-shift to be established in the diffusion zone around the electrode (i.e. non-manually). This pH-shift leads to the protonation of a dissolved polyanionic polymer which in consequence changes significantly its solubility and is hence precipitating on the electrode surface. In the presence of a suitable enzyme, such as quinohemoprotein alcohol dehydrogenase (QH-ADH), the polymer precipitation leads to an entrapment of the redox enzyme within the polymer film. Simultaneously, the water-soluble Os-poly(vinyl-imidazole) redox hydrogel, which is slowly dissolving from the electrode surface after addition of the electrolyte, is co-entrapped within the precipitating polymer layer. This provides the pre-requisite for an efficient electron-transfer pathway from the redox enzyme via the polymer-bound redox centres to the electrode surface. The sensor preparation protocol has been optimised aiming on a high mediator concentration in the polymer film and an effective electron transfer.
authors.affiliation: Institute of Biochemistry, Mokslininku 12, LT-2600 Vilnius, Lithuania.
authors.forename: Aiste
authors.initials: A
authors.lastname: Vilkanauskyte
authors.forename: Thomas
authors.initials: T
authors.lastname: Erichsen
authors.forename: Liucija
authors.initials: L
authors.lastname: Marcinkeviciene
authors.forename: Valdas
authors.initials: V
authors.lastname: Laurinavicius
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schuhmann
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry*; D000438:Alcohols / Q000032:analysis / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002138:Calibration; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004800:Enzymes, Immobilized / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D000431:Ethanol / Q000032:analysis* / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry; D007202:Indicators and Reagents; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012995:Solubility
chemical_list: D000438:Alcohols; D004800:Enzymes, Immobilized; D020100:Hydrogels; D007202:Indicators and Reagents; D011108:Polymers; D000431:Ethanol; D000429:Alcohol Oxidoreductases; C019641:alcohol dehydrogenase (acceptor)