Study On The Aptamer-Based Novel Methods For The Detection Of Bisphenol A

A large number of studies have found that Bisphenol A (BPA) is an environmental endocrine disrupting compound with carcinogenic, teratogenic and mutagenic effects on humans and can affect the growth and development of infants and young children. Traditional methods for BPA detection have the advantages of high sensitivity, good repeatability, and so on. However, they also have the disadvantages of high cost, needing sophisticated instruments and complex pretreatment. Aptamer has been widely used in the area of detection for its selective binding with targets. Therefore, three different colorimetric assays were developed for rapid BPA detection based on BPA-specific aptamers in this paper:(1) A method for the detection of BPA that is based on the use of AuNPs functionalized with an aptamer labeled with a horseradish peroxidase mimick was developed. The assay is based on the high affinity between aptamer and BPA, and on the finding that AuNPs display HRP-like properties in catalyzing the oxidation of 3,3,5,5-tetramethylbenzidine to give a blue reaction product with a maximum absorption at 652 nm. The limit of detection for thrombin is as low as 6.79 nM, and the analytical range extends from 6.79 to 1500 nM BPA.(2) A colorimetric method based on BPA-specific aptamer, surfactant CTAB and AuNPs for the detection of BPA was developed. CTAB can (a) react with BPA-specific aptamer forming the super molecular and (b) induce the aggregation of AuNPs leading the color changes. Under the optimal condition, the limit of detection (LOD) of the method was 3.2 nM and the detection range was 0.032 ?M?2.0 uM. In addition, this colorimetric method was applied to determine spiked BPA in water samples with mean recovery of 100.1%?108.5%.(3) A colorimetric method was exploited to detect BPA based on aptamer and cationic polymer and AuNPs. The key to this method was that PDDA can (a) react with aptamer to form a "duplex" structure and (b) break the electrostatic equilibrium of AuNPs and make the aggregation of AuNPs. This method can be used to detect BPA with good selectivity and the detection range and limit of detection were 1.50?500 nM and 1.50 nM, respectively. In addition, it was successfully used to determine spiked BPA concentrations with recoveries between 100.9 and 112.7% and the relative standard deviations in the range of 6.72-13.10%.