A simple one-step pretreatment, highly sensitive and selective sensing of 17β-estradiol in environmental water samples using surface-enhanced Raman spectroscopy

A highly sensitive and selective aptamer-based surface-enhanced Raman spectroscopic biosensing system was established for detecting trace amount of 17 beta-estradiol (E2) for the first time, and applied in the environmental samples based on a simple one-step pretreatment. Raman reporter molecule 4-mercaptobenzoic acid labelled gold-silver core-shell nanoparticles (Au@Ag CS NPs) and E2-aptamer endowed SERS with high sensitivity and selectivity. A wide linear range from 0.1 pM to 10 nM was obtained for the detection of E2, with a low detection limit of 0.05 pM. Additionally, this system showed excellent selectivity for E2, where the Raman intensity of E2 was greater than 3.97-fold that of 100-fold concentration of other interfering substances. The high binding affinity of the E2-aptamer towards E2 was further investigated by the UV-vis absorption measurements, whereas E2-aptamer showed no binding affinity to other interferents. Finally, E2 in the environmental water samples collected from the sewer and nearby river of local obstetric hospital were successfully determined by this system, which exhibited superior sensitivity. This work has provided a new detection biosensing system for trace determination of typical contaminants in the environment. (C) 2017 Elsevier B.V. All rights reserved.