A photoelectrochemical aptasensor for the detection of 17β-estradiol based on In2S3 and CdS co-sensitized cerium doped TiO2

Abstract

In this work, a photoelectrochemical (PEC) aptasensor for the detection of 17β-estradiol (E2) based on an In₂S₃ and CdS co-sensitized cerium (Ce) doped TiO₂ (Ce:TiO₂) electrode was constructed successfully. In₂S₃ with superior properties, such as narrow band gap, attractive photoelectric conversion efficiency, hypotoxicity and low pollution, could act as a promising material in the PEC sensing detection field. Here, a PEC aptasensor based on In₂S₃ was fabricated for the detection of E2. Besides, Ce doped into TiO₂ introduced a new intrinsic energy band into TiO₂, which created an easier electron transfer path. In₂S₃ and CdS co-loaded on Ce:TiO₂ not only improved the photocurrent response but also expanded the light absorption range. Meanwhile, an aptamer with a specific sequence, serving as a recognition unit, was used to specifically bind with E2 to enable detection. Under optimal conditions, the as-prepared aptasensor exhibited a linearity range of 10⁻⁵–100 ng mL⁻¹ with a detection limit of 4.0 fg mL⁻¹. The aptasensor also showed satisfactory selectivity, stability and acceptable reproducibility.