span style="font-size:15.0pt;mso-bidi-font-size:11.0pt" lang="EN-US"A superoxide anion electrochemical sensor based on the direct electrochemistry of superoxide dismutase assembled layer-by-layer at the L-cysteine modified gold electrode /span

摘要

A superoxide anion (O2?–) biosensor has been developed based on layer-by-layer assembled poly-(diallyldimethylammonium) (PDDA) and superoxide dismutase (SOD) on the L-cysteine (Cys) modified gold (Au) electrode. In 25 mM phosphate buffer solution (pH 7.2), the {SOD/PDDA}n/Cys/Au electrode shows a pair of well-defined and nearly reversible peak at ~ 84 mV vs SCE, confirming the direct electrochemistry of SOD. Based on the bifunctional enzymatic catalytic activities of SOD to the oxidation and reduction of O2?–, the developed {SOD/PDDA}5/Cys/Au electrode exhibits good analytical characteristics in the detection of O2?–, such as low detection limit, good stability, reproducibility, selectivity and particularly a wide linear range (0.5 ~ 546 mM).