Ultrasensitive detection of Bisphenol A based on an aptasensor with DNA amplification

ABSTRACTAn ultrasensitive and selective method for Bisphenol A (BPA) detection using aptamer-BPA and real-time quantitative polymerase chain reaction (RT-qPCR) technology is reported, in which biotin-modified aptamer DNA (BPA) is fixed on the inner wall of a streptavidin-coated PCR tube via biotin–avidin interactions and the template is fixed through the complementary base pairing with aptamer DNA. Upon the addition of BPA, the template DNA could be off from the inner wall of PCR tube, which results from aptamer DNA interacted specifically with BPA. Thus, the number of template DNA change result from the BPA concentration is readily seen by cycle threshold (Ct) values. The sensor exhibited an excellent linear response between Ct values and BPA concentration in the range of 1–500 nM and the detection limit of this method for aqueous BPA was as low as 0.7 nM. In addition, this method showed good selectivity for BPA over its analogues.