Flow Injection Amperometric Detection at Enzyme‐Modified Gold Nanoelectrodes

Abstract

Gold nanotubular electrode ensembles were prepared by using electroless deposition of the metal within the pores of polycarbonate particle track-etched membranes. Glucose oxidase (Gox), used as a model enzyme, has been immobilized onto preformed self-assembled monolayers (mercaptoethylamine or mercaptopropionic acid) on electroless gold via cross-linking with glutaraldehyde or covalent attachment by carbodiimide coupling. Flowinjection analysis systems in flow-through or wall-jet configurations using these Gox-modified nanoelectrodes are described. The influence of different experimental parameters (i.e., applied potential, flow rate, interferents...) on the analytical response of the sensor to glucose has been evaluated. Under optimized conditions, very reproducible results (standard deviations < 4%, n 38) were obtained, linear calibration was achieved in the 2 Â 10 À4 M to 3 Â 10 À2 M concentration range and the detection limit was 2 Â 10 À4 M. Moreover, no significant interferences from species like ascorbic and uric acids were observed at a potential of 0.9 V.

3D‐Ensembles of Gold Nanowires: Preparation, Characterization and Electroanalytical Peculiarities

“…For many electroanalytical applications the surface of electrodes in general, and NEEs in particular [19,20] can be modified either with catalysts, mediators or molecular recognition elements. Therefore the electrochemical behavior of surface-confined redox species was also examined here on the etched NEEs.…”

Gold nanoelectrode ensembles for direct trace electroanalysis of iodide

“…NEEs are useful electrochemical tools for biosensors development [40,41], for the measurement of (high) charge transfer rate constants [35] and for solving adsorption related problems [36]. With respect to the latter issue, it was shown that operating in very diluted solutions of the analytes (thanks to the very low detection limits achievable at NEEs) it was possible to obtain diffusion-controlled responses even for molecules such as some phenothiazines [35] or redox proteins such as cytochrome c [36], which can adsorb on electrode surfaces.…”

Development of Low Cost Rapid Fabrication of Sharp Polymer Microneedles for In Vivo Glucose Biosensing Applications

“…33,34 However, a key limitation in this approach is the requirement for molecular oxygen as an oxidising agent. Further to this, relatively high overpotentials are required to reduce oxygen or oxidize the enzymatic product H 2 O 2 , is also sufficient to reduce or oxidize common interferents normally present in biological fluids.…”