A simple, competitive biosensor for rapid detection of aflatoxin B1 based on aggregation of gold nanorods

A novel optical biosensor based on gold nanorods (GNRs) was designed and fabricated for simple, sensitive and competitive detection of aflatoxin B1 (AFB1). Free AFB1 target interacted with capture antibodies, competing with AFB1-BSA (Bovine serum albumin) conjugate modified GNRs. Aggregation of GNRs was observed if the amount of AFB1 target was not enough. As a result, an associated decrease in the absorbance of the GNRs was induced, which served as the sensing indicator. It was illustrated that a linear correlation existed between the absorbance of GNRs and the logarithmic value of AFB1 concentrations from 0.1 to 20 ppb (ng·mL^-1). And the limit of detection reached as low as 0.04 ppb.