Adsorption of Laccase on Multi-walled Carbon Nanotubes

Controlling redox enzyme adsorption on an electrode surface is a key feature for designing efficient and stable bioelectrodes for biofuel cell applications. Here, we report an analysis of the adsorption mechanism of laccase, which catalyzes the 4-electron reduction reaction of oxygen, on multi-walled carbon nanotubes (MWCNTs). The adsorption of laccase on the surface of MWCNTs can be explained by the Langmuir model with a pseudo-first-order kinetics. We found that laccase adsorption is an exothermic process, mainly driven by hydrophobic interactions between laccase and the MWCNTs. Our investigation also revealed that electrostatic interactions are not the main driving forces and play a small role in laccase adsorption. A clear understanding and devising an efficient method of enzyme adsorption will provide important guidelines for optimizing, not only the surface material design but also the adsorption method for high-performance electrodes.