title: Enhanced Photoelectrochemical Immunosensing Platform Based on CdSeTe@CdS:Mn Core-Shell Quantum Dots-Sensitized TiO2 Amplified by CuS Nanocrystals Conjugated Signal Antibodies.
abstract: A new, ultrasensitive photoelectrochemical immunosensing platform was established on the basis of CdSeTe@CdS:Mn core-shell quantum dots-sensitized TiO2 coupled with signal amplification of CuS nanocrystals conjugated signal antibodies. In this proposal, carcinoembryonic antigen (CEA, Ag) was selected as an example of target analyte to show the analytical performances of the platform. Specifically, TiO2-modified electrode was first assembled with CdSeTe alloyed quantum dots (AQDs) via electrostatic adsorption assisted by oppositely charged polyelectrolyte, and then further deposited with CdS:Mn shells on the surface of CdSeTe AQDs via successive ionic layer adsorption and reaction strategy, forming TiO2/CdSeTe@CdS:Mn sensitization structure, which was used as photoelectrochemical matrix to immobilize capture CEA antibodies (Ab1); signal CEA antibodies (Ab2) were labeled with CuS nanocrystals (NCs) to form Ab2-CuS conjugates, which were employed as signal amplification elements when specific immunoreaction occurred. The ultrahigh sensitivity of this immunoassay resulted from the following two aspects. Before detection of target Ag, the TiO2/CdSeTe@CdS:Mn sensitization structure could adequately harvest the exciting light with different bands, evidently expedite the electron transfer, and effectively depress the charge recombination, resulting in noticeably increased photocurrent. When target Ag existed, the Ab2-CuS conjugates could dramatically decrease the photocurrent due to competitive absorption of exciting light and consumption of electron donor for CuS NCs coupled with steric hindrance of Ab2 molecules. The fabricated photoelectrochemical immunosensor showed a low limit of detection of 0.16 pg/mL and a wide linear range from 0.5 pg/mL to 100 ng/mL for CEA detection, and it also exhibited good specificity, reproducibility, and stability.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, People's Republic of China.|School of Mechanical and Materials Engineering, Washington State University , Pullman, Washington 99164, United States.
authors.forename: Gao-Chao
authors.initials: GC
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, People's Republic of China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhu
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University , Pullman, Washington 99164, United States.
authors.forename: Dan
authors.initials: D
authors.lastname: Du
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, People's Republic of China.|School of Chemistry and Life Science, Nanjing University Jinling College , Nanjing 210089, People's Republic of China.
authors.forename: Jian-Rong
authors.initials: JR
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, People's Republic of China.
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Zhu
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University , Pullman, Washington 99164, United States.
authors.forename: Yuehe
authors.initials: Y
authors.lastname: Lin
mesh_terms: D000906:Antibodies / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D045663:Quantum Dots; D013440:Sulfides / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D000906:Antibodies; D019187:Cadmium Compounds; D013440:Sulfides; C009495:titanium dioxide; C099343:cuprous sulfide; D003300:Copper; D014025:Titanium