Step-by-step electrodeposition of a high-performance Prussian blue-gold nanocomposite for H2O2 sensing and glucose biosensing

A Prussian blue (PB)-gold nanocomposite ((PB-Au)x, where x denotes the number of PB-Au bilayer) is prepared, by step-by-step electrodeposition of PB and gold on a glassy carbon electrode (GCE). The optimized (PB-Au)2/GCE exhibits excellent electrocatalytic activity for electroreduction of H2O2, and the cathodic current at − 0.05 V responds linearly to H2O2 concentration up to 3.88 mM with a sensitivity of 1.32 mA mM− 1 cm− 2, which outperforms the gold-PB nanocomposites electrodeposited through other reported protocols. Moreover, a glucose oxidase (GOx)-polydopamine (PDA)-Pt nanoparticles (PtNPs) bionanocomposite is synthesized through chemical oxidation of dopamine by sodium chloroplatinate in the presence of GOx. A chitosan (CS)/GOx-PDA-PtNPs/(PB-Au)2/GCE is fabricated by casting GOx-PDA-PtNPs and then CS on (PB-Au)2/GCE. The cathodic current at − 0.05 V on this enzyme electrode responds linearly to glucose concentration from 5 μM to 0.79 mM with a sensitivity of 114 μA mM− 1 cm− 2 and a LOD of 0.5 μM (S/N = 3). The presented protocol can flexibly balance the high catalytic activity and the poor electron-conductance of PB for improving the electroactivity and electrocatalytic activity of PB-based films, thus yielding high-performance PB-based electrodes for low-potential determination of H2O2 and glucose.