Amperometric biosensor for hydrogen peroxide and nitrite based on hemoglobin immobilized on one-dimensional gold nanoparticle

Hemoglobin (Hb) was immobilized on one-dimensional (1D) gold (Au) nanoparticles to construct a novel amperometric biosensor for hydrogen peroxide (H₂O₂) and nitrite (NO₂^-). 1D Au nanoparticles were prepared by electrodepositon in the pores of an alumina template and were characterized by XRD and TEM. The immobilized Hb retained its biological activity well and displayed a good response to the reduction of both H₂O₂ and NO₂^-. Its apparent Michaelis-Menten constants for H₂O₂ and NO₂^- were 10.8 and 35.3 μM, respectively, showing a good affinity. Under optimal conditions, the biosensors could be used for the determination of H₂O₂ ranging from 0.6 to 12.4 μM and NO₂^- ranging from 0.4 to 14.8 μM. The detection limits were 2.4 × 10^-8 and 6.5 × 10^-8 M at 3σ, respectively. 1D Au nanoparticles provided a good matrix for protein immobilization and biosensor preparation.