Kourosh Motevalli - Applied Chemistry Department, Fundamental Sciences Faculty, Islamic Azad University, South Tehran Branch
Zahra Yaghoubi - Industrial Faculty, Islamic Azad University, South Tehran Branch, Tehran, Iran

A new amperometric biosensor for hydrogen peroxide (H2O2) has been developed that is based on direct electrochemistry and electrocatalysis of hemoglobin (Hb) in a multilayer inorganic–organic hybrid film. o-Phenylenediamine (PDA) was electro- polymerized onto a glassy carbon electrode (GCE), and then negatively charged nanosilver particles and positively charged poly (diallyldimethylammonium chloride) (PDDA) were alternately assembled on the PDA=GCE surface. Finally, Hb was electrostatically adsorbed on the surface of silver nanoparticles. The electrochemical behavior of the resulting biosensor (Hb={nanosilver=PDDA}n=PDA=GCE) was assessed and optimized. The performance and factors influencing the biosensor were studied in detail. Under optimal conditions, the immobilized Hb displayed good electrocatalytic response to the H2O2 reduction ranging from 1.3 mM to 1.4 mM with a detection limit of 0.8 mM. In addition, the biosensor exhibited rapid response, good reproducibility, and long-term stability

Direct electrochemistry; silver nanoparticles; hemoglobin biosensor; multilayer inorganic–organic hybrid film