Amine intercalated clay surfaces for microbial cell immobilization and biosensing applications

WOS: 000318302900050Trimethylamine (TM) intercalated montmorillonite (Mont) clay was prepared and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential and thermal gravimetric measurements. Gluconobacter oxydans cells were immobilized on the micro-structured matrix and used in microbial sensor applications. Sensor responses were based on the respiratory activity of the cells and the consumption of oxygen was monitored at 20.7 V (vs. Ag/AgCl and platinum electrodes) by using glucose as a substrate. Stabilization of the bacteria was performed on the Mont using glutaraldehyde. Optimization of the TM-Mont/G. oxydans sensor and examination of the electrochemical mechanism were carried out in a batch system. Measurements concerning analytical characteristics, operational stability, repeatability and substrate specificity depending on the carbon source in the culture were investigated in a flow injection analysis (FIA) system. Linear ranges were found between 0.15 and 5.0 mM for the batch mode and 0.1 and 5.0 mM for the FIA system, respectively. Finally, real samples were analyzed and were compared with the results of a spectrophotometric method as reference

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

WOS: 000334753200017Present study reports the use of a glassy carbon electrode modified with manganese oxide decorated with platinum nanoparticles (Pt-MnOx/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 K2PtCl6 and 0.1 M MnSO4 in 0.01 M H2SO4 solution. Then, the electrode developed was utilized as a biosensing platform for the monitoring of oxygen consumption due to the bie-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 mu M and sensitivity of 6.1 nA mu M-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. (C) 2014 Elsevier B.V. All rights reserved.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); Ege University Research FoundationEge University [2013/FEN/060]This study was supported by TUBITAK 2209 program and Ege University Research Foundation (Project no: 2013/FEN/060)