Development of a tyrosinase-based biosensor for bisphenol A detection using gold leaf-like microstructures

A simple one-step electrodeposition without template allowed the synthesis of gold microstructures on a screen-printed carbon electrode. Chloroauric ions were reduced by applying a constant potential of -0.6V during 600s. A preferential growth along the <111> directions produced leaf-like structures as confirmed by scanning electron microscopy and X-ray diffraction. The as-prepared Au microstructures worked as a support for tyrosinase immobilization allowing the preparation of a highly selective and sensitive biosensor for bisphenol A (BPA) detection. The cyclic voltammograms exhibit a well-defined anodic peak at 0.24V in phosphate buffer solution (0.1molL(-1), pH7.0). The enzyme creates favorable conditions for the adsorption of BPA, and after 10min of accumulation time, the calibration curve was linear in the range of 0.5-50molL(-1) with a detection limit of 77nmolL(-1) (S/N=3) and a relative standard deviation (RSD%) of 0.54% (n=10). Furthermore, the proposed biosensor displayed long-term stability and was successfully applied to determine BPA in spiked water samples.