Photocurrent-polarity-switching photoelectrochemical and electrochemical dual-mode sensing platform for the highly selective detection of trenbolone

As an emerging contaminant in the environment, trenbolone (TBE) has aroused a global health crisis and caused the huge impact on ecosystem. Its sensitive detection is critical to safeguard human health and ecosystem. Herein, a photocurrent polarity switching photoelectrochemical (PEC)-electrochemical (EC) dual-mode sensing platform was presented for highly selective and sensitive detection of TBE by ingeniously tailor signal probe. The tailored Cu2O@CuO-hemin acting as both photocurrent polarity reversal and electroactivity factor were cross-linked with TBE-BSA to obtain competitive conjugates for TBE. When the competitive response was initiated, numerous of Cu2O@CuO-hemin nanocomposites are introduced on the CdS-modified indium tin oxide electrode, serving as the reporting agent of EC/PEC dual-mode assay. The photocurrent polarity of the CdS-modified ITO can be effectively switched, enabling PEC analysis of TBE with distinguishing photocurrent changes. The linear response range is 1 pg/mL to 500 ng/mL, and the detection limit is 15.0 fg/mL. Meanwhile, the Cu2O@CuO could triggered the amplified current variations via effectually catalyzing the H2O2 decomposition compared to the CdS NPs, leading to the sensitive electrochemical detection of TBE with a detection limit 200 fg/mL and a linear response range from1 pg/mL to 500 ng/mL. Additionally, the developed sensing platform enabled mutual authentication of PEC/EC detection results, being conducive to increasing the assay reliability and accuracy. Such the dual-mode sensor has great potential for detecting environmental pollutants due to its improved selectivity and mutual authentication of results.