title: A competitive photoelectrochemical assay for estradiol based on in situ generated CdS-enhanced TiO2.
abstract: A novel and simple photoelectrochemical (PEC) bioassay protocol for estradiol was proposed based on in situ generated CdS-enhanced TiO2 film via competitive strategy. The CdS was generated in situ by immediately dropping S(2-) onto the Cd(2+)-functionalized titanium phosphate nanoparticles (TiP@Cd(2+)). The TiO2 photoactive sensing film with countless active sites was obtained by calcination and further explored for estradiol (E2) capture. The TiP@Cd(2+) was used as labels and immobilized through affinity-specific binding with E2 on the surface of the electrode. Greatly enhanced sensitivity was achieved by using porous TiP nanoparticles as carriers to load a large amount of Cd(2+) and further for more CdS production through the S(2-) deposition. What's more, the photocurrent of CdS generated on the electrode surface could be significantly amplified by the coupling of CdS and TiO2, which could enhance the excitation and photo-to-electric conversion efficiency. Through the application of a competitive binding assay, the proposed biosensor showed high sensitivity with a detection limit down to 2pg/mL. This simple and fast PEC E2-sensing approach offers great promise to extend its application for the assay of small molecules of biomedical, food and environmental interest. Additionally, the strategy of employing in situ generated narrow-band gap semiconductors paves a new way for PEC sensing.
authors.affiliation: School of Resources and Environment, University of Jinan, Jinan 250022, PR China.
authors.forename: Rongxia
authors.initials: R
authors.lastname: Li
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yan
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Yueyun
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wei
authors.affiliation: School of Resources and Environment, University of Jinan, Jinan 250022, PR China. Electronic address: dubin61@gmail.com.
authors.forename: Bin
authors.initials: B
authors.lastname: Du
mesh_terms: D001667:Binding, Competitive; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D019187:Cadmium Compounds; D055664:Electrochemical Techniques; D004958:Estradiol / Q000032:analysis*; D006801:Humans; D053768:Metal Nanoparticles / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D015203:Reproducibility of Results; D013440:Sulfides; D017971:Tin Compounds; D014025:Titanium
chemical_list: D019187:Cadmium Compounds; D013440:Sulfides; D017971:Tin Compounds; C034939:cadmium sulfide; C009495:titanium dioxide; D004958:Estradiol; C109984:indium tin oxide; D014025:Titanium
keywords: Competitive bioassay; In situ; Photoelectrochemical; Small molecules