Hydrogen Peroxide Biosensor Based on Immobilization of Hemoglobin on Au@Ag Nanoparticles Modified Carbon Ionic Liquid Electrode

Abstract

Abstract A hydrogen peroxide (H 2 O 2 ) biosensor based on the combination of Au@Ag core‐shell nanoparticles with a hemoglobin‐chitosan‐1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate (Hb‐CHIT‐BMIM×BF 4 ) composite film was prepared. UV‐vis spectroscopy and transmission electron microscopy confirmed a core‐shell nanostructure of Au@Ag nanoparticle was successfully obtained. Cyclic voltammetric results showed a pair of well‐defined redox peaks appeared with the formal potential ( E O′ ) of ‐0.301 V (versus Ag/AgCl reference electrode) and the peak‐to‐peak separation (Δ E p ) was 84 mV in 0.1 M phosphate buffer solutions. Due to the synergetic effect of Au@Ag core‐shell nanoparticles and Hb‐CHIT‐BMIM×BF 4 , the biosensor exhibited good electrocatalytic activity to the reduction of H 2 O 2 in a linear range from 1.0 × 10 −6 to 1.0 × 10 −3 M with a detection limit of 4 × 10 −7 M (S/N = 3). The apparent Michaelis‐Menten constant ( K M ) was estimated to be 4.4 × 10 −4 M, showing its high affinity. Thus, the study proved that the combination of Au@Ag core‐shell nanoparticles and Hb‐CHIT‐BMIM×BF 4 is able to open up new opportunities for the design of enzymatic biosensors.