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

Hemoglobin (Hb) was immobilized on one-dimensional (I D) 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 mu M, 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 mu M and NO2- ranging from 0.4 to 14.8 mu M. The detection limits were 2.4 x 10(-8) and 6.5 x 10(-8) M at 3 sigma. respectively. 1D Au nanoparticles provided a good matrix for protein immobilization and biosensor preparation. (C) 2009 Elsevier B.V. All rights reserved.