Dependence of Catalytic Dynamics on Structural and Operational Parameters of Enzymatic Electrodes Based on Nano-composite

Abstract Dependences of structural parameters and operational conditions on enzymatic catalysis of substrates (glucose and oxygen) for basal electrodes over-coated by composite consisting of nano-gold particle and polymer, were investigated systematically by the means of electrochemistry and spectrometry. Rate constants of steps involved in the whole catalytic cycle were estimated under the same dimension and were compared to confirm the limiting factor in the whole catalytic cycle. Results from experiments indicated that nano-gold particle surface anchored with aromatic ring as conductive support played the important role in achieving direct electron transfer between cofactors in redox protein molecules and electrical wired matrix. Complexations between components of nano-composite and redox sites within incorporated enzyme molecules acted as the paradoxical role in promoting the catalytic efficiency in the long term. Electrochemical conversion of substrates into product was identified to be the rate limiting step in the whole catalytic cycle for both enzyme based electrodes. Other parameters such as enzyme loading amounts in matrix, size of nano-particle and proportion of component in nano-composite only posed impact on magnitude of catalytic effect rather than the mechanism of catalysis. Graphical Abstract Transformation of substrate into product was ascribed to the limiting step in the whole catalysis for enzyme-based electrodes which resulted from great impact of interactions between enzyme carrier and redox protein on configuration of cofactors in enzyme molecules and binding ability to substrate for proteins.