title: A visible light photoelectrochemical sensor for tumor marker detection using tin dioxide quantum dot-graphene as labels.
abstract: In this paper, a simple and sensitive sandwich-type photoelectrochemical (PEC) immunosensor for measurement of biomarkers on a gold nanoparticle-modified indium tin oxide (ITO) electrode through electrodeposition for point-of-care testing was developed by using a tin dioxide quantum dot-graphene nanocomposite (G-SnO2) as an excellent label with amplification techniques. The capture antibody (Ab1) was firstly immobilized on the gold nanoparticle-modified ITO electrode due to the covalent conjugation, then the antigen and the AuNP/PDDA-G-SnO2 nanocomposite nanoparticle labeled signal antibody (Ab2) were conjugated successively to form a sandwich-type immunocomplex through a specific interaction. Under irradiation with a common ultraviolet lamp (∼365 nm, price $50), the SnO2 NPs were excited and underwent charge-separation to yield electrons (e(-)) and holes (h(+)). As the holes were scavenged by ascorbic acid (AA), the electrons were transferred to the ITO electrode through RGO to generate a photocurrent. The photocurrents were proportional to the CEA concentrations, and the linear range of the developed immunosensor was from 0.005 to 10 ng mL(-1) with a detection limit of 0.036 pg mL(-1). The proposed sensor shows high sensitivity, stability, reproducibility, and can become a promising platform for other biomolecular detection.
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P.R. China. ujn.yujh@gmail.com.
authors.forename: Yanhu
authors.initials: Y
authors.lastname: Wang
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.forename: Yuanna
authors.initials: Y
authors.lastname: Zhu
authors.forename: Shenguang
authors.initials: S
authors.lastname: Ge
authors.forename: Jinghua
authors.initials: J
authors.lastname: Yu
authors.forename: Mei
authors.initials: M
authors.lastname: Yan
authors.forename: Xianrang
authors.initials: X
authors.lastname: Song
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D008027:Light; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D009369:Neoplasms / Q000175:diagnosis*; D055668:Photochemical Processes; D045663:Quantum Dots; D017971:Tin Compounds / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D017971:Tin Compounds; D006046:Gold; D006108:Graphite; C045358:stannic oxide; D001205:Ascorbic Acid