title: Using silver nanocluster/graphene nanocomposite to enhance photoelectrochemical activity of CdS:Mn/TiO2 for highly sensitive signal-on immunoassay.
abstract: A highly sensitive signal-on photoelectrochemical (PEC) immunosensor was fabricated here using CdS:Mn/TiO2 as photoelectrochemical sensing platform, and silver nanoclusters and graphene naocomposites (AgNCs-GR) as signal amplification tags. The immunosensor was constructed based on the specific sandwich immunoreaction, and the photo-to-current conversion efficiency of the isolated protein modified CdS:Mn/TiO2 matrix was improved based on the synergistic effect of AgNCs-GR. Under irradiation, the photogenerated electrons from the AgNCs at a higher conduction band edge level could be transport to the CdS:Mn/TiO2 matrix with the assistance of highly conductive graphene nanosheets, as well as recycle the trapped excitons in the defects-rich CdS:Mn/TiO2 interface. The electron transport and exciton recycle reduced the possibility of electron-hole recombination and greatly improved the photo-to-current conversion efficiency of the sensing matrix. Based on the signal enhancement, a signal-on PEC immunosensors was fabricated for the detection of carcinoembryonic antigen (CEA), a model analyte related to many malignant diseases. Under optimal conditions, the as-prepared immunosensor showed excellent analytical performance, with a wide linear range from 1.0 pg/mL to 100 ng/mL and a low limit of detection of 1.0 pg/mL. The signal-on mode provided 2.48 times higher sensitivity compared with signal-off mode. This strategy demonstrated good accuracy and high selectivity for practical sample analysis, thus may have great application prospective in the prediction and early diagnosis of diseases.
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Song
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China.
authors.forename: Jiamian
authors.initials: J
authors.lastname: Wang
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China.
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China. Electronic address: wushuo@dlut.edu.cn.
authors.forename: Shuo
authors.initials: S
authors.lastname: Wu
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China.
authors.forename: Zhanming
authors.initials: Z
authors.lastname: Gao
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China.
authors.forename: Jingli
authors.initials: J
authors.lastname: Yuan
authors.affiliation: School of Chemistry, Dalian University of Technology, Dalian 116023, PR China.
authors.forename: Changgong
authors.initials: C
authors.lastname: Meng
mesh_terms: D015374:Biosensing Techniques; D002272:Carcinoembryonic Antigen / Q000302:isolation & purification*; D055664:Electrochemical Techniques; D006108:Graphite / Q000737:chemistry; D006801:Humans; D007118:Immunoassay; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D014025:Titanium / Q000737:chemistry
chemical_list: D002272:Carcinoembryonic Antigen; C009495:titanium dioxide; D012834:Silver; D006108:Graphite; D014025:Titanium
keywords: CdS:Mn/TiO(2); Enhanced photo-to-current conversion efficiency; Photoelectrochemical immunoassay; Signal-on; Silver nanocluster and graphene nanocomposite