Immobilizing haemoglobin on gold/graphene-chitosan nanocomposite as efficient hydrogen peroxide biosensor

A method is reported for the preparation of novel electrode by layer-by-layer assembly of haemoglobin (Hb), gold (Au) nanoparticles, chitosan (CS) and graphene (GR) onto glassy carbon electrode (GCE). The Au/GR-CS substrate shows an obvious promotion for the direct electron transfer between Hb and GCE. The surface concentration (Gamma*) of Hb on the as-modified electrode can be as high as 4.33 x 10(-9) mol/cm(2), which is 228 times higher than the theoretical value for Hb monolayer on bare GCE. The Au/GR-CS/GCE shows good electrocatalytic performance for the reduction of hydrogen peroxide within a linear range from 2 to 935 mu M, a low detection limit of 0.35 mu M (S/N = 3) and high sensitivity of 347.1 mA cm(-2) M-1. The Au/GR-CS nanocomposite demonstrates as a versatile matrix for immobilizing redox protein to realize direct electrochemistry and hence prepare efficient and robust biosensor. (C) 2014 Elsevier B.V. All rights reserved.