An Ultrasensitive and Highly Selective Electrochemical Aptasensor for Environmental Endocrine Disrupter Bisphenol A Determination Using Gold Nanoparticles/Nitrogen, Sulfur, and Phosphorus Co-Doped Carbon Dots as Signal Enhancer and Its Electrochemical Kinetic Research

Abstract

Electrochemistry will bring revolutionary detection methods for bisphenol A (BPA) which is a endocrine disrupter. Electrochemical aptasensor appears to be a promising approach to this end because of its brilliant specificity, high affinity, low cost and rapid response time. However, electrochemical aptasensor suffers from reducing signal when anti-BPA aptamers are modified on electrode surface. In response, we report an electrochemical aptasensor based on gold nanoparticles (AuNPs) and nitrogen, sulfur, and phosphorus co-doped carbon dots (N,S,P-CDs) modified glassy carbon electrode(GCE) for amplified signal detection of BPA. The thiol-gold (S-Au) bonds between the AuNPs and the thiol termini on anti-BPA aptamers anchor the anti-BPA aptamers to the GCE. N,S,P-CDs as electrode modifications are applied to expand the active area and enhance electron-transport ability. In this work, the presences of N,S,P-CDs and the AuNPs were assessed via Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD), etc. The sensing scheme and electrochemical response of the proposed sensor were investigated by chronocoulometry (CC), cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and differential pulse voltammetry (DPV). Meanwhile, we focused on discussing the kinetic parameters of [Fe(CN)6]3−/4− on the composite electrode that had reacted with BPA, such as active surface areas (A), surface concentration (Г0), the standard rate constant (k) and electron transfer coefficient (α). Aptasensor revealed a high sensitivity and had a linear electrochemical response to BPA in the concentration range of 0.01 μM–120 μM, with a low detection limit of 5.273 × 10−10 M. Moreover, the proposed aptasensor could be applied for the detection of BPA in real samples with great precision, high sensitivity, excellent selectivity, brilliant reproducibility and satisfactory results. Therefore, this convenient and sensitive aptasensor is proved to a promising and reliable tool for detecting BPA in food and environmental pollution.