Aptamer-based impedimetric label-free detection of bisphenol A from water samples using a gold nanoparticle-modified electrochemical nanofilm platform

A label-free impedimetric aptasensor for bisphenol A (BPA) was developed based on a novel method. Initially, gold nanoparticle-based nanoplatforms were prepared using a 4-mercaptophenyl (4MP) electrochemical nanofilm. Then, the BPA-selective aptamer (antiBPA) was immobilized on this platform for the sensitive and selective detection of BPA. The characterizations of the electrode preparation steps were performed using a transmission electron microscope, X-ray photoelectron spectroscopy, electrochemical methods, and atomic force microscopy. The aptamer immobilization concentration, immobilization time, and incubation time of BPA were optimized to get the best sensor response. The calibration curve exhibited good linearity between 10 fM and 10 nM with a correlation coefficient of 0.9963 and a limit of detection and limit of quantification values of 8.6 and 25.8 fM (S/N = 3), respectively. The developed aptasensor showed good reproducibility (RSD 2.55%), high sensitivity, specificity, and stability. The developed sensor was validated using real samples of tap water, lake water, and wastewater demonstrating promising performance. [GRAPHICS]

Automated summary

A label-free impedimetric aptasensor for bisphenol A (BPA) was developed based on a novel method, using gold nanoparticle-based nanoplatforms and BPA-selective aptamer immobilization. The sensor showed good linearity, sensitivity, specificity, and stability, with a limit of detection of 8.6 fM and limit of quantification of 25.8 fM.