title: Direct electron transfer between cytochrome P450scc and gold nanoparticles on screen-printed rhodium-graphite electrodes.
abstract: This paper is concerned with an investigation of electron transfer between cytochrome P450scc (CYP11A1) and gold nanoparticles immobilised on rhodium-graphite electrodes. Thin films of gold nanoparticles were deposited onto the rhodium-graphite electrodes by drop casting. Cytochrome P450scc was deposited onto both gold nanoparticle modified and bare rhodium-graphite electrodes. Cyclic voltammetry indicated enhanced activity of the enzyme at the gold nanoparticle modified surface. The role of the nanoparticles in mediating electron transfer to the cytochrome P450scc was verified using ac impedance spectroscopy. Equivalent circuit analysis of the impedance spectra was performed and the values of the individual components estimated. On addition of aliquots of cholesterol to the electrolyte bioelectrocatalytic reduction currents were obtained. The sensitivity of the nanoparticle modified biosensor to cholesterol was 0.13 microA microM-1 in a detection range between 10 and 70 microM of cholesterol. This confirms that gold nanoparticles enhance electron transfer to the P450scc when present on the rhodium-graphite electrodes.
authors.affiliation: Institute of Biomedical Chemistry, Pogodinskaya st. 10, Moscow 119121, Russia.
authors.forename: Victoria V
authors.initials: VV
authors.lastname: Shumyantseva
authors.forename: Sandro
authors.initials: S
authors.lastname: Carrara
authors.forename: Valter
authors.initials: V
authors.lastname: Bavastrello
authors.forename: D
authors.initials: D
authors.lastname: Jason Riley
authors.forename: Tatiana V
authors.initials: TV
authors.lastname: Bulko
authors.forename: Konstantin G
authors.initials: KG
authors.lastname: Skryabin
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Archakov
authors.forename: Claudio
authors.initials: C
authors.lastname: Nicolini
mesh_terms: D015374:Biosensing Techniques; D002784:Cholesterol / Q000032:analysis; D002786:Cholesterol Side-Chain Cleavage Enzyme; D004566:Electrodes; D004579:Electron Transport; D006046:Gold; D006108:Graphite; D049329:Nanostructures; D012238:Rhodium
chemical_list: D006046:Gold; D006108:Graphite; D002784:Cholesterol; D012238:Rhodium; D002786:Cholesterol Side-Chain Cleavage Enzyme