A highly sensitive NADH sensor based on a mycelium-like nanocomposite using graphene oxide and multi-walled carbon nanotubes to co-immobilize poly(luminol) and poly(neutral red) hybrid films

Abstract

Hybridization of poly(luminol) (PLM) and poly(neutral red) (PNR) has been successfully performed and further enhanced by a conductive and steric hybrid nanotemplate using graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs). The morphology of the PLM–PNR–MWCNT–GO mycelium-like nanocomposite is studied by SEM and AFM and it is found to be electroactive, pH-dependent, and stable in the electrochemical system. It shows electrocatalytic activity towards NADH with a high current response and low overpotential. Using amperometry, it has been shown to have a high sensitivity of 288.9 μA mM⁻¹ cm⁻² to NADH (E_app. = +0.1 V). Linearity is estimated in a concentration range of 1.33 × 10⁻⁸ to 1.95 × 10⁻⁴ M with a detection limit of 1.33 × 10⁻⁸ M (S/N = 3). Particularly, it also shows another linear range of 2.08 × 10⁻⁴ to 5.81 × 10⁻⁴ M with a sensitivity of 151.3 μA mM⁻¹ cm⁻². The hybridization and activity of PLM and PNR can be effectively enhanced by MWCNTs and GO, resulting in an active hybrid nanocomposite for determination of NADH.