Highly sensitive and group-targeting detection of steroid estrogens in water environment using a valid...

Steroid environmental estrogens (SEEs) are often coexist in water, require complex analytical techniques for separation and monitoring. However, aptamer-based chemical detection often only recognizes one of them, and the detection of SEEs is still a huge challenge. Herein, a group-targeting aptamer with the ability to recognize SEEs was constructed using efficient oligonucleotide class-specific editing technology, and a photoelectrochemical aptasensor capable of detecting the class of SEEs was established. A quantitative analysis of highly toxic SEEs in the environment and carrying similar core carbon skeleton, including 17β-estradiol, esterone, estriol and ethinylestradiol, was performed. The detection limit was as low as 0.1 nM with a response time of only 15 min. Specifically, this method exhibited high anti-interference with different complex media existing. Combining the theoretical calculations with a variety of spectral experiments, the Π-Π stacking and hydrogen bond synergistic interactions between the photoelectric interface and the three ring structures on SEEs and the hydroxyl group of ring 1 were analyzed in depth. Besides, the conformational changes of loose base helix structure and the free rotation limitation of oligonucleotides after the recognition of SEEs at the molecular level were also elucidated, facilitating the transfer of electrons on the surface of the photoelectrode.