Layer-by-Layer Assembly of Carbon Nanotubes Modified with Invertase/Glucose Dehydrogenase Cascade for Sucrose/O 2 Biofuel Cell

Abstract

© The Author(s) 2016. A layer-by-layer (LbL) assembly technique was employed to modify glassy carbon electrodes (GCEs) and screen printed electrodes (SPEs) utilizing multiwalled carbon nanotubes (MWCNTs)/polyelectrolyte binary composites and an enzyme cascade to facilitate efficient electron transfer in sucrose/O 2 biofuel cell. In this study, MWCNTs immobilized invertase (INV) and glucose dehydrogenase (GDH) were alternatively assembled upon polyethyleneimine (PEI) and DNA nanocomposites to construct a bioanode. [Ni(phendion)(phen)]Cl 2 complex and methylene green (MG) were investigated as redox mediators for electrocatalytic oxidation of NADH at reduced overpotentials. The LbL architecture showed advantages for sequential enzymatic reaction that favored the efficient penetration of substrate and products in a cascade system while MWCNTs facilitated the efficient electron transfer from sucrose oxidation and enhancement of the current density. With a GCE bioanode modified with a MG or Ni complex, the biofuel cell produced a higher power density (μW/cm 2 ) with 145.8% and 130.11% enhancement comparing to a SPE bioanode, respectively. Moreover, the Ni complex modified GCEs and SPEs produced power densities (μW/cm 2 ) 93.7% and 107.0% higher compared to MG modified bioanodes, respectively. The maximum current density of 1400 ± 46 μA/cm 2 was obtained with the Ni complex on GCE at an OCP of 604 ± 17 mV with a maximum power density of 405 ± 6 μW/cm 2 . The LbL assembly showed great feasibility as a simple and efficient way to construct controlled MWCNT-multi-enzyme modified electrodes for biofuel cell applications.