Simple and rapid detection of bisphenol A using a gold nanoparticle-based colorimetric aptasensor

A colorimetric aptasensor was developed for the simple and rapid detection of bisphenol A (BPA). The aptasensor was designed to consist of colloidal gold nanoparticles (AuNPs) and a BPA-specific 24-bp aptamer. The AuNP-aptamer conjugates underwent an electrolyte-induced aggregation in the presence of sub-ppb levels of BPA. The surface plasmon resonance shift of AuNPs facilitated a color change from red to blue upon aggregation, which was visually observed by the naked eye. The corresponding visual limit of detection of BPA was as low as 1 pg/mL (0.004 nM). The aptasensor also achieved a selective detection of BPA over a variety of BPA analogs. The applicability of the aptasensor was verified via a successful detection of BPA in a single grain of rice. This result indicates that the colorimetric aptasensor can be used in a screening procedure for food and environmental monitoring, with reliable performance to sub-ppb levels of BPA detection.