Non-Faradaic aptasensor based on NH2-GO/PPy for the detection of 17β-estradiol.

17ß-Estradiol (E2) is an endocrine-disrupting chemical that has become a matter of concern across the globe for more than a decade due to potential health risks. This study reports facile methods to fabricate label-free aptasensor based on the non-Faradaic impedance mode using amine-functionalized graphene oxide polypyrrole (NH2-GO/PPy)-modified gold interdigitated electrode for direct capacitive detection of 17β-estradiol. The as-prepared NH2-GO/PPy nanocomposites have been successfully characterized by field-emission scanning electron microscopy (FESEM), atomic force microscopy, Fourier transform infrared spectroscopy, and electrochemical impedance spectroscopy. The results show that NH2-GO/PPy/IDE was able to detect E2 binding through aptamer conformational change by simply observing the capacitance change before and after immobilization. In addition, the biosensor showed a dynamic range of detection from 100 nM to 1 pM with a low detection limit of about 0.13 pM. The recoveries result also presented in this paper was validated using HPLC exhibited high sensitivity for bisphenol-A (BPA) detection and was successfully applied to detect E2 in real water samples with good recoveries. [ABSTRACT FROM AUTHOR]