DNA-based biosensors with polyvinyl alcohol external membrane as a tool for the evaluation of antioxidant activity of white wines

Electrochemical DNA-based biosensors with external protective membranes were prepared for the evaluation of antioxidant properties of white wines against pro-oxidant hydroxyl radicals. A glassy carbon working electrode (GCE) was modified using a layer-by-layer deposition technique with low molecular weight double stranded DNA and an outer sphere polymer film membrane of Nafion, chitosan or polyvinylalcohol. The composition of a working procedure with membrane-covered DNA biosensors were optimized with respect to their voltammetric response in solution of the DNA redox indicator [Fe(CN)₆]^3-/^4- after the incubation in white wines. Polyvinylalcohol (PVA) film was proved to be the suitable membrane. The PVA/DNA/GCE biosensor was used for the detection of a deep degradation of the surface-attached DNA at the incubation in the cleavage agent and for the evaluation of antioxidant properties of white wines at the incubation in mixtures of cleavage agent and wine. The investigation of the biosensors with protective membranes represents a significant contribution to utilization of the electrochemical DNA based biosensors for practical purposes.