Investigation of the mechanism of adsorption of β-nicotinamide adenine dinucleotide on single-walled carbon nanotubes

We address in this manuscript the important issue of the stability of single-walledcarbonnanotube(SWCNT)-based electrodes upon oxidation of NADH to NAD⁺. NADH and NAD⁺ play a key role in the development of electrochemical enzyme-based biofuel cells and biosensors. However, most of the electrode materials exhibit strong surface passivation when oxidation of NADH to NAD⁺ occurs. SWCNT-based electrodes are not affected bysuch apassivation effect.In the present work, we address the fundamental question, "why are the single-walled carbon nanotube electrodes prone topassivation?" using electrochemical methods and first-principles molecular dynamics simulations. We found that this is due to the wide exposed surface of SWCNT-based electrodes rather than other "inherent" properties of SWCNTs, such as the electrocatalytic effect and high curvature.