Enzyme-free glucose sensor based on a three-dimensional gold film electrode

An enzyme-free glucose sensor has been developed using a three-dimensional inverse-opal gold film electrode (3DGFE) obtained by electrochemical deposition of gold in the interspaces of polystyrene templates. The gold films were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV). The electrochemical oxidation of glucose in the presence of interferents (ascorbic acid, and so on) at different operating potentials on the 3DGFE has been investigated in detail. A low operating potential of −0.30 V was chosen for glucose detection, since the interference could be well avoided at this potential, whereas the current response for glucose oxidation was still sensitive. The amperometric response of the sensor increased with the increase of glucose concentration with a linear range of 5 × 10−6 to 10−2 M and a detection limit of 3.2 μM (signal-to-noise ratio of 3). The glucose sensor exhibited a high sensitivity of 46.6 μA mM−1 cm−2, which could be ascribed to the unique surface structure of the three-dimensionally interconnected porous structured gold films. The sensor with high sensitivity, good selectivity and stability is attractive for the practical glucose detection.