title: Ionic liquid functionalized graphene based immunosensor for sensitive detection of carbohydrate antigen 15-3 integrated with Cd(2+)-functionalized nanoporous TiO2 as labels.
abstract: A novel electrochemical immunosensor for sensitive detection of carbohydrate antigen 15-3 (CA15-3) based on dual signal amplification strategy of ionic liquid functionalized graphene and Cd(2+)-functionalized nanoporous TiO2 (f-TiO2-Cd(2+)) has been developed. Ionic liquid functionalized graphene was used to anchor primary CA15-3 antibody (Ab1). f-TiO2-Cd(2+) was employed to immobilize secondary cancer antigen 15-3 (CA15-3) antibody (Ab2) and the resulting nanocomposite (Ab2-f-TiO2-Cd(2+)) was used as trace tag for signal amplification. The fabricated immumosensor displayed a wide range of linear response (0.02-60 U/mL), ultra-low detection limit (0.008 U/mL), good reproducibility, selectivity and stability towards CA15-3. The good performance of the immunosensor can be attributed to (1) high surface-to-volume ratio of graphene which allows high-level immobilization of Ab1, (2) excellent biocompatibility and electron transfer rate originating from ionic liquid functionalized graphene, (3) a highly specific surface area of nanoporous TiO2 that facilitates the adsorption of high amount of Cd(2+) for signal amplification.
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Lifang
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, 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 Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Wu
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Jinke
authors.initials: J
authors.lastname: Dou
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China; School of Life Science and Biotechnology, University of Jinan, Jinan 250022, China. Electronic address: lihecd@gmail.com.
authors.forename: He
authors.initials: H
authors.lastname: Li
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D002104:Cadmium / Q000737:chemistry*; D004867:Equipment Design; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D052578:Ionic Liquids / Q000737:chemistry*; D057230:Limit of Detection; D018396:Mucin-1 / Q000032:analysis*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D016062:Porosity; D014025:Titanium / Q000737:chemistry*
chemical_list: D055910:Antibodies, Immobilized; D052578:Ionic Liquids; D018396:Mucin-1; D002104:Cadmium; C009495:titanium dioxide; D006108:Graphite; D014025:Titanium
keywords: Carbohydrate antigen 15-3.; Electrochemical immunosensor; Graphene; Ionic liquid; Nanoporous titanium dioxide