A visual detection of bisphenol A based on peroxidase-like activity of hemin-graphene composites and aptamer

Herein, a fast and visible colorimetric method for bisphenol A (BPA) detection was developed using hemin-functionalized reduced graphene oxide (H-rGO) composites and aptamer. The aptamer can be stably adsorbed on the surface of H-rGO, preventing H-rGO from salt-induced aggregation. However, in the presence of BPA, the aptamer can bind with BPA; this results in the aggregation of H-rGO. Consequently, the supernatant contains a little H-rGO and shows light blue color after the chromogenic reaction. The color difference can be used for the quantitative detection of BPA. The designed aptasensor displayed a linear response for BPA in the range from 5 nM to 100 nM with a detection limit of 2 nM. This colorimetric aptasensing platform offered great advantages, including label-free conditions and visible result readout platform, for quick screening of BPA for on-site analysis and in-house diagnosis.