Mo-doped porous BiVO4/Bi2S3 nanoarray to enhance photoelectrochemical efficiency for quantitative detection of 17β-estradiol

A new porous nanoarray is constructed as sensing platform of photoelectrochemical (PEC) biosensor for detection of 17 beta-estradiol (E2) by using aptamer. The molybdenum (Mo) ions doped into porous bismuth vanadate (Mo-p BiVO4) nanoarray by electrodeposition of BiOI nanoarray. Then, the bismuth sulfide (Bi2S3) nanoparticles are grown in-situ on the surface of Mo-p BiVO4 by the self-sacrificial synthesis method to form novel Mo-p BiVO4/Bi2S3 heterojunction. Herein, the Mo-p BiVO4/Bi2S3 heterojunction presents a high PEC signal because of Mo-p BiVO4 could increase electron-hole separation yield by supplying additional free electrons, furthermore the heterojunction of Mo-p BiVO4/Bi2S3 could promote ultrafast transfer of charge and inhibit the recombination of e(-)/h(+) pairs by presenting cascade band-edge levels under irradiation of the visible light. Moreover, the nanoarray structure has large specific surface area, which could accelerate electron transfer and provide large number of binding sites to immobilize aptamer. This PEC aptamer sensor exhibits high sensitivity with a detection limit 3.2x10(-4) pM and a good photocurrent response toward target E2 in the range of 1x10(-3) - 5x10(2) pM. Good specificity and stability are acquired for analysis of E2 in human urine. Importantly, this designed sensor platform of Mo-p BiVO4/Bi2S3 heterojunction provides a new promising application for other environmental estrogen analysis.