A self-powered photoelectrochemical cathodic aptasensor for the detection of 17β-estradiol based on FeOOH/In2S3 photoanode

In this work, a novel self-powered photoelectrochemical (PEC) aptasensor integrated photoanode and photocathode for the accurate and selective detection of 17β-estradiol (E2) was proposed for the first time. FeOOH/In2S3 heterojunction was built initially and used as a substitute for platinum (Pt) counter electrode. The matched band gap edge of FeOOH and In2S3 facilitated the transfer of photo-generate electrons to photoanode, while the holes left in the valence band of photocathode (CuInS2) can be attracted by the electrons flowed from the photoanode, which reduced the recombination of electron-hole pairs and promote the cathodic photocurrent. Under optimal conditions, the constructed cathodic aptasensor of E2 presented linear scope in 10 fg/mL-1 μg/mL with detection limit of 3.65 fg/mL. Besides, the cathodic aptasensor exhibited admiring selectivity, stability and reproducibility. This work verified that the cathodic photocurrent response can be regulated by the corresponding photoanode which provided a new design thought for PEC aptasensor on the basis of p-type semiconductor.