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

A hydrogen peroxide (H2O2) biosensor based on the combination of Au@Ag core-shell nanoparticles with a hemoglobin-chitosan-1-butyl-3-methyl-imidazolium tetrafluoroborate (Hb-CHIT-BMIM center dot BF4) 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-0') of -0.301 V (versus Ag/AgCl reference electrode) and the peak-to-peak separation (Delta 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 center dot BF4, the biosensor exhibited good electrocatalytic activity to the reduction of H2O2 in a linear range from 1.0 x 10(-6) to 1.0 x 10(-3) M with a detection limit of 4 x 10(-7) M (S/N = 3). The apparent Michaelis-Menten constant (K-M) was estimated to be 4.4 x 10(-4) M, showing its high affinity. Thus, the study proved that the combination of Au@Ag core-shell nanoparticles and Hb-CHIT-BMIM center dot BF4 is able to open up new opportunities for the design of enzymatic biosensors.