Development of electrochemical sensors based on plasma-treated polymeric nanostructures for sensitive and reproducible detection of bisphenol A

Significant public health concerns have been raised regarding humans' ubiquitous exposure to bisphenol A (BPA), an endocrine-disrupting chemical, through dietary and environmental pathways. In this study, for the sensitive detection of BPA, we developed three different electrochemical sensors (i.e., Au film, Au nanodimple (AuND), and Au nanopillar (AuNP)) and investigated the influence of electroactive surface area on electrochemical sensing performance. The supporting polymeric nanostructures (i.e., NDs and NPs) were developed using facile plasma treatment processes. Cyclic voltammetry and electrochemical impedance spectroscopy were used to evaluate the electrodes' electroactivity. Compared with the other electrode materials (i.e., Au film and AuNDs), the AuNPs, which exhibited a high density and high aspect ratio, showed excellent redox behaviors and low charge transfer resistance. A quantitative investigation of BPA was conducted using differential pulse voltammetry. Under optimal experimental conditions, the AuNP sensors demonstrated a linear response (R² = 0.98), nanomolar sensitivity, and high reproducibility (relative standard deviation ≤ 3.1 %) in the dynamic BPA concentration range from 2 to 1000 nM. The viability of the AuNP sensors in practical applications was also examined with BPA-spiked artificial tear and urine samples. The results highlight that the electrochemical sensors implanted with AuNP platforms are suitable for monitoring BPA in contaminated water and biofluids.