Pyranose oxidase and Pt–MnOx bionanocomposite electrode bridged by ionic liquid for biosensing applications

Abstract Present study reports the use of a glassy carbon electrode modified with manganese oxide decorated with platinum nanoparticles (Pt–MnO x /GCE) for electrocatalytic reduction of oxygen dissolved in buffer solution. The electrode exhibits better electrocatalytic activity toward oxygen reduction than bulk platinum due to larger surface area of manganese oxide which also prevents agglomeration of platinum nanoparticles. Best results were obtained with the electrode modified by cycling the potential in a range of −0.25–1.05 V for five times in a cell containing 1.0 mM K 2 PtCl 6 and 0.1 M MnSO 4 in 0.01 M H 2 SO 4 solution. Then, the electrode developed was utilized as a biosensing platform for the monitoring of oxygen consumption due to the bio-catalytic activity of pyranose oxidase. In the pursuit of a stable and rapid response the biocomponent was bridged with an ionic liquid namely 1-butyl-3-methyl imidazolium hexaflourophosphate. Chronoamperometric measurement of oxygen at 0.2 V gave 0.010–0.100 mM linear range with a detection limit of 2.0 μM and sensitivity of 6.1 nA μM −1 under optimized conditions. In addition, ionic liquid provides a conductive environment which shortens the response time to 3 s for low concentrations. Overall results indicated that fabricated biosensor is a good candidate for automated systems.