title: An ultrasensitive label-free immunosensor based on CdS sensitized Fe-TiO2 with high visible-light photoelectrochemical activity.
abstract: An ultrasensitive label-free immunosensor was developed for the detection of squamous cell carcinoma antigen (SCCA) based on CdS sensitized Fe-TiO2 nanocomposites with high visible-light photoelectrochemical (PEC) activity. In this protocol, ascorbic acid was used as an efficient electron donor for scavenging photogenerated holes. The Fe-doped TiO2 improved the absorption of TiO2 in the visible light region and promoted the photocurrent production distinctly. Especially, 0.1% Fe-TiO2 showed the highest photocurrent, which was 7.4 times that of pure TiO2. Carboxyl functionalized CdS nanoparticles (CdS NPs) were bonded onto Fe-TiO2 composite through interactions between carboxyl groups and TiO2, which further enhanced the PEC signal strength by approximately 2.9 fold compared with 0.1% Fe-TiO2. The specific binding between SCCA and antibody resulted in a decrease in photocurrent intensity and the intensity decreased linearly with the logarithm of SCCA concentration in the range of 0.001-75 ng mL(-1) with a detection limit of 0.22 pg mL(-1). The developed CdS enhanced Fe-TiO2 PEC immunosensor exhibited high sensitivity, good reproducibility, and low cost, which may have potential applications in clinical diagnosis of cancers, aptasensors, photocatalysis, and other related fields.
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in University of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Fan
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in University of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in University of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Jiali
authors.initials: J
authors.lastname: Cui
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in University of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in University of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Hongmin
authors.initials: H
authors.lastname: Ma
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in University of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in University of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wei
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in University of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China. Electronic address: dubin61@gmail.com.
authors.forename: Bin
authors.initials: B
authors.lastname: Du
mesh_terms: D000951:Antigens, Neoplasm / Q000737:chemistry / Q000302:isolation & purification*; D015374:Biosensing Techniques; D019187:Cadmium Compounds / Q000737:chemistry; D055664:Electrochemical Techniques; D006801:Humans; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D055668:Photochemical Processes; D045663:Quantum Dots; D015843:Serpins / Q000737:chemistry / Q000302:isolation & purification*; D013431:Sulfates / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D000951:Antigens, Neoplasm; D019187:Cadmium Compounds; D015843:Serpins; D013431:Sulfates; C051072:squamous cell carcinoma-related antigen; C009495:titanium dioxide; C037123:cadmium sulfate; D014025:Titanium
keywords: CdS; Fe–TiO(2); Label-free; Photoelectrochemical sensor; Squamous cell carcinoma antigen