Layer-by-layer self-assembly of glucose oxidase and Os(Bpy)(2)CIPyCH2NH-poly(allylamine) bioelectrode

The uptake of glucose oxidase (GOx) onto a polycationic redox polymer (PAA- Os)-modified surface, by adsorption from dilute aqueous GOx solutions, was followed by the quartz crystal microbalance (QCM) and shows double exponen tial kinetics. The electrochemistry of the layer-by-layer-deposited redox-a ctive polymer was followed by cyclic voltammetry in glucose-free solutions, and the enzyme, catalysis mediated by the redox polymer was studied in P-D -glucose-containing solutions. AFM studies of the different layers showed t he existence of large two dimension enzyme aggregates on the osmium polymer for 1 muM GOx and less aggregation for 50 nM GOx solutions. When the short alkanethiol, 2,2'-diaminoethyldisulfide was preadsorbed onto gold, a monoe xponential adsorption law was observed, and single GOx enzyme molecules cou ld be seen on the surface where the enzyme was adsorbed from 50 nM GOx in w ater.