Aptamer based surface plasmon resonance sensor for aflatoxin B1

The authors describe a surface plasmon resonance (SPR) based aptasensor for the carcinogenic mycotoxin aflatoxin B1 (AFB1) in a direct assay format. The aptamer is immobilized on the surface of a commercial sensor chip, and the SPR signal increases on binding of AFB1. The sensor chip can be fully regenerated by passing a flow of buffer over it upon which bound AFB1 dissociates from the aptamer. The biosensor works in the 0.4 nM to 200 nM AFB1 concentration range and has a 0.4 nM detection limit. It allows AFB1 to be determined in complex samples such as diluted red wine and beer. The assay is sensitive, and the chip is easily regenerated and stable. The method therefore overcomes certain limitations of antibody-based SPR assays and of competitive SPR assays for AFB1.