In2O3/AgBiS2 heterojunction – gated organic photoelectrochemical transistor with DNAzyme-mediated reaction for sensitive detection of bisphenol A

Abstract

In recent years, organic photoelectrochemical transistor (OPECT) sensors have attracted growing attention in various fields. Nevertheless, their potential remains far from being fully exploited, and these systems still face substantial challenges. In this work, a novel OPECT aptamer biosensor is rationally designed and fabricated by integrating photoelectrochemical analysis with organic electrochemical transistor technology. In this sensor, In₂O₃/AgBiS₂ is employed as the photoactive material, and target-specific DNA strand displacement hybridization is utilized as the signal amplification strategy. Specifically, for bisphenol A (BPA) detection, DNAzyme (G-quadruplex/hemin) acts as a horseradish peroxidase (HRP) mimic to catalyze H₂O₂-mediated oxidation reactions, generating insoluble precipitation, which markedly decreases ΔI_DS. Experimental verification shows that the developed sensor exhibits excellent analytical performance. Its linear detection range can cover from 1 fg mL⁻¹ to 0.1 ng mL⁻¹, and the limit of detection is as low as 0.29 fg mL⁻¹. This innovative biosensing platform not only provides a highly potential solution for the accurate detection of BPA but also shows broad application prospects and great development potential in the future expansion of the analysis and detection of other pollutants.