title: Au nanoparticle-enhanced surface plasmon resonance sensing of biocatalytic transformations.
abstract: N-(3-Aminopropyl)-N'-methyl-4,4'-bipyridinium is coupled to tiopronin-capped Au nanoparticles (diameter ca. 2 nm) to yield methyl(aminopropyl)viologen-functionalized Au nanoparticles (MPAV(2+)-Au nanoparticles). In situ electrochemical surface plasmon resonance (SPR) measurements are used to follow the electrochemical deposition of the bipyridinium radical cation modified Au nanoparticles on an Au-coated glass surface and the reoxidation and dissolution of the bipyridinium radical cation film. The MPAV(2+)-functionalized Au nanoparticles are also employed for the amplified SPR detection of NAD(+) and NADH cofactors. By SPR monitoring the partial biocatalyzed dissolution of the bipyridinium radical cation film in the presence of diaphorase (DP) NAD(+) is detected in the concentration range of 1x10(-4) M to 2x10(-3) M. Similarly, the diaphorase-mediated formation of the bipyridinium radical cation film on the Au-coated glass surface by the reduction of the MPAV(2+)-functionalized Au nanoparticles by NADH is used for the amplified SPR detection of NADH in the concentration range of 1x10(-4) M to 1x10(-3) M.
authors.affiliation: Institute of Chemistry and The Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Maya
authors.initials: M
authors.lastname: Zayats
authors.forename: Svetlana P
authors.initials: SP
authors.lastname: Pogorelova
authors.forename: Andrei B
authors.initials: AB
authors.lastname: Kharitonov
authors.forename: Oleg
authors.initials: O
authors.lastname: Lioubashevski
authors.forename: Eugenii
authors.initials: E
authors.lastname: Katz
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D001711:Biotransformation; D002384:Catalysis; D002412:Cations / Q000737:chemistry; D004563:Electrochemistry; D005898:Glass / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D009243:NAD / Q000737:chemistry; D036103:Nanotechnology; D010084:Oxidation-Reduction; D010316:Particle Size; D011726:Pyridinium Compounds / Q000737:chemistry; D020349:Surface Plasmon Resonance / Q000379:methods*; D013997:Time Factors; D008625:Tiopronin / Q000737:chemistry
chemical_list: D002412:Cations; D011726:Pyridinium Compounds; D009243:NAD; D006046:Gold; D008625:Tiopronin