Square Wave Voltammetric Detection of Chemical DNA Damage with Catalytic Poly(4-Vinylpyridine)−Ru(bpy)₂²⁺ Films

Abstract

Reversible, catalytic films of poly(4-vinylpyridine)-Ru(bpy)2(2+) [PVP-Ru(bpy)2(2+), bpy = 2,2'-bipyridine] on pyrolytic graphite (PG) electrodes were evaluated for the detection of damage to double-stranded (ds) DNA by using square wave voltammetry (SWV). Damage of both calf thymus and salmon testes ds-DNA in solution was induced by incubation of DNA at 37 degrees C with styrene oxide, the liver metabolite of styrene, and a suspected carcinogen. Both types of ds-DNA incubated in solution with saturated styrene oxide gave a linear increase in catalytic peak current up to 30 min, and an estimate of two damaged DNA bases in one thousand could be detected. The increase in catalytic current is attributed to better access of the catalyst redox sites to oxidizable bases in the damaged, partly unwound DNA. A self-contained "toxicity sensor" was also evaluated, which consisted of films of [PVP-Ru(bpy)2(2+)] on PG electrodes coated with films of ds-DNA and polydiallyldimethylammonium polycations assembled layer-by-layer. These films also gave an increase in catalytic peak current upon incubation in saturated styrene oxide, and an estimate of 1 damaged base in 1000 could be detected. Control films or solutions of ds-DNA treated in buffer or buffer containing unreactive toluene resulted in no significant changes in the catalytic peak current with incubation time.

Studies of DNA Damage Inhibition by Dietary Antioxidants Using Metallopolyion/DNA Sensors

“…An increase in current occurred for the Ru peak with a small but reproducible increase in current at the Os peak. This is consistent with the oxidation of styrene to the epoxide which reacts with DNA, leading to detection of the resulting damaged DNA by the catalytic Ru peak increase [23,24].…”

“…Because of this disruption, remaining undamaged guanines become more accessible to the catalyst, and are more easily oxidized. For this reason, the formation of nucleobase adducts in DNA can be detected by catalytic voltammetry using the ClRuPVP films [23,24]. Figure 3a shows SWV of the ClRu-PVP/PSS/ClOs-PVP/DNA/PDDA/DNA sensor before and after incubation for 8 minutes in buffer saturated with styrene oxide.…”

Recent Updates of Chemically Modified Electrodes in Analytical Chemistry

“…Kimura et al rationalized the pH-sensing electrode using a sol gel-based ionomeric system (tretradecyldimethyl(3-rimethoxysilylproyl)ammonium chloride) and crown ether derivative (bis(12-crown-4-methyl)dodecylmethylmalonate) for simultaneous potentiometric sensing of Na and Cl À ions [84]. Rusling and co-workers introduce polymer pendant type of modified electrode by coating PVP as the underlying support to anchor Ru(bpy) 2 Cl 2 complex [85]. Such studies were well established in polymer supported solution phase catalytic system [86].…”

A Novel Electrochemical Sensor Based on [Ru(NH3)6]Cl3 as a Redox Indicator for the Detection of G-G Mismatched DNA

“…Electrochemical detection platforms have been widely applied, which benefit from a fast response, reliable, simple instrumentation, ease of miniaturization, high sensitivity and selectivity. [4][5][6][7] Various electrochemical measurement protocols have been used, including square-wave voltammetry, 8,9 differential pulse voltammetry (DPV), 10 cyclic voltammetry (CV) 11 and electrochemical impedance spectroscopy (EIS). 12 DPV exhibited the new prospect because of its high sensitivity, high accuracy, easy operation, and wide applicable range.…”