Electrochemical impedance spectroscopy characterization of nanoporous alumina dengue virus biosensor

The Faradaic electrochemical impedance technique is employed to characterize the impedance change of a nanoporous alumina biosensor in response towards the specific binding of dengue serotype 2 (Denv2) viral particles to its serotype 2-specific immunoglobulin G antibody within the thin alumina layer. The optimal equivalent circuit model that matches the impedimetric responses of the sensor describes three distinct regions: the electrolyte solution (R-s), the porous alumina channels (including biomaterials) (Q(1), R-1) and the conductive electrode substrate layer (Q(2), R-2). Both channel resistance R-1 and capacitance Q(1) change in response to the increase of the Denv2 virus concentration. A linear relationship between R-1 and Denv2 concentration from 1 to 900 plaque forming unit per mL (pfu mL(-1)) can be derived using Langmuir-Freundlich isotherm model. At 1 pfu mL(-1) Denv2 concentration, R-1 can be distinguished from that of the cell culture control sample. Moreover, Q(1) doubles when Denv2 is added but remains unchanged in the presence of two other nonspecific viruses - West Nile virus and Chikungunya virus indicates biosensor specificity can be quantitatively measured using channel capacitance. (C) 2012 Elsevier B.V. All rights reserved.