title: Ultrasensitive electrochemical immunosensor for carbohydrate antigen 19-9 using Au/porous graphene nanocomposites as platform and Au@Pd core/shell bimetallic functionalized graphene nanocomposites as signal enhancers.
abstract: A facile and feasible sandwich-type electrochemical immunosensor for ultrasensitive determination of Carbohydrate antigen 19-9 (CA19-9) was designed by using Au nanoparticles functionalized porous graphene (Au-PGO) as sensing platform and Au@Pd core/shell bimetallic functionalized graphene nanocomposites (Au@Pd-Gra) as signal enhancers. Herein, Au@Pd-Gra with a large surface area was prepared for immobilizing plentiful of redox probe-thionine (Thi), horseradish peroxidase (HRP) and secondary antibodies (Ab2), leading to the formation of Au@Pd-Gra/Thi-Ab2/HRP bioconjugate which exhibited satisfying electrochemical redox activity, high electrocatalytic activity and friendly biocompatibility. With the synergistic effect between Au@Pd-Gra and HRP, almost triple amplified detection signal was achieved in the presence of H2O2, so as to improve the detection limit of the proposed immunosensor effectively. Furthermore, Au-PGO was utilized as the biosensor platform which could greatly enhance the surface area to immobilize a large amount of captured primary antibodies (Ab1) leading a further enhancement in the sensitivity of immunosensor. Under optimal conditions, the electrochemical immunosensor exhibited desirable performance for determination of CA19-9 with a wide linearity in the range from 0.015 to 150UmL(-1) and a relatively low detection limit of 0.006UmL(-1). Importantly, the resulted immunosensor displayed good specificity and high sensitivity, implying potential applications in clinical research.
authors.affiliation: Key Laboratory of Luminescence and Real-Time Analytical Chemistry, Education Ministry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Key Laboratory of Luminescence and Real-Time Analytical Chemistry, Education Ministry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Zhehan
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Key Laboratory of Luminescence and Real-Time Analytical Chemistry, Education Ministry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.affiliation: Key Laboratory of Luminescence and Real-Time Analytical Chemistry, Education Ministry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yqchai@swu.edu.cn.
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.affiliation: Key Laboratory of Luminescence and Real-Time Analytical Chemistry, Education Ministry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yuanruo@swu.edu.cn.
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation; D018395:CA-19-9 Antigen / Q000097:blood*; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*
chemical_list: D055910:Antibodies, Immobilized; D018395:CA-19-9 Antigen; D010087:Oxides; D010165:Palladium; D006046:Gold; D006108:Graphite
keywords: Au nanoparticles functionalized porous graphene; Au@Pd core/shell bimetallic functionalized graphene; Carbohydrate antigen 19-9.; Immunosensor