Enhanced electron transfer for hemoglobin entrapped in a cationic gemini surfactant films on electrode and the fabrication of nitric oxide biosensor

The direct electrical communication between hemoglobin (Hb) and GCE surface was achieved based on the immobilization of Hb in a cationic gemini surfactant film and characterized by electrochemical techniques. The cyclic voltammograms showed that direct electron transfer between Hb and electrode surface was obviously promoted and then a novel unmediated nitric oxide (NO) biosensor was constructed in view of this protein-based electrode. This modified electrode showed an enzyme-like activity towards the reduction of NO and its amperometric response to NO was well-behaved with a rapid response time and displaying Michaelis-Menten kinetics with a calculated K-m(app) value of 84.37 mu mol L-1. The detection limit was estimated to be 2.00 x 10(-8) mol L-1. This biosensor was behaving as expected that it had a good stability and reproducibility, a higher sensitivity and selectivity and should has a potential application in monitoring NO released from biologic samples. (C) 2007 Elsevier B.V. All rights reserved.