Aptamer-based fluorescent detection of bisphenol A using nonconjugated gold nanoparticles and CdTe quantum dots

A novel aptamer-based fluorescent method for the analysis of bisphenol A (BPA) has been developed based on the specific recognition of aptamers and the inner filter effect (WE) of gold nanoparticles (AuNPs) on the fluorescence of CdTe quantum dots (CdTe QDs). The fluorescence of CdTe QDs could be significantly quenched by AuNPs via the IFE. The IFE efficiency can be adjusted by BPA in that the specific recognition between BPA and aptamers could show different influences on the salt-induced aggregation of AuNPs, and correspondingly modulate the IFE process. Under optimum conditions, a good linear correlation to BPA concentration was exhibited from 10 ng/mL to 80 ng/mL (R-2=0.99) with the detection limit of 1.86 ng/mL, which was lower than the Maximum Residue Limits of BPA in drinking water. This assay showed excellent selectivity towards BPA over other BPA analogues. The application of this method for tap water samples obtained satisfactory recoveries in accordance with those from HPLC method. The proposed fluorescent method exhibits excellent advantages of high sensitivity, excellent selectivity and simple operation procedure, thus it would be suitable for the on-site and real-time screening of target in real samples. (C) 2015 Elsevier B.V. All rights reserved.