Fabrication of layer-by-layer deposited multilayer films containing DNA and gold nanoparticle for norepinephrine biosensor

The present work describes the preparation and characterization of an electrodeposited DNA membrane (loped with gold nanoparticles for the design of biosensors. The gold nanoparticles were deposited on the surface of DNA layer to build a hybrid device of nanoscale electrode array. The gold nanoparticles -doped DNA composite electrode was characterized by atomic force microscopy, scanning electron microscope, and electrochemistry involving electrochemical impedance spectroscopy. This electrode was successfully used for selective determination of norepinephrine (NE) in the presence of ascorbic acid (AA). The reversibility of the electrode oxidation reaction of NE is significantly improved in result of 200 mV negative shift of the voltammetric peak potential on the electrode, and a large increase in the peak current. A detection limit of 5 nM NE is obtained by using DPV in static solutions. The co-existence of a large excess of AA does not interfere with the detection. This electrode shows excellent sensitivity, good selectivity and antifouling properties. (C) 2004 Elsevier B.V. All rights reserved.