Immobilization of L-lysine alpha-oxidase on gold-mercaptopropionic acid self-assembled monolayer: preparation and electrochemical characterization.

Immobilization of L-lysine alpha-oxidase on gold-mercaptopropionic acid self-assembled monolayer (Au-MPA-LOx SAM) electrode is verified experimentally in the present work. Fabrication steps and electrochemical interaction of Au-MPA-LOx with L-lysine were monitored by general electrochemical methods like cyclic voltammetry (CV) and chronoamperometry (CA), and by a more advanced method, electrochemical impedance spectroscopy (EIS) in the presence of parabenzoquinone (PBQ) redox probe. The data was analyzed from which quantitative kinetic parameters were extracted. The results confirmed successful immobilization of LOx, and thus, fabrication of Au-MPA-LOx SAM electrode. Our initial tests revealed a linear response for Au-MPA-LOx SAM electrode toward L-lysine concentration in solution at biological conditions, pH 7.4. The experimental data will be presented and discussed from which the Au-MPA-LOx SAM electrode is characterized, and the kinetic merits of the interface interactions are introduced.