title: An ultrasensitive sandwich-type electrochemical immunosensor based on signal amplification strategy of gold nanoparticles functionalized magnetic multi-walled carbon nanotubes loaded with lead ions.
abstract: In this study, a novel and ultrasensitive sandwich-type electrochemical immunosensor was prepared for the quantitative detection of alpha fetoprotein (AFP), a well-known hepatocellular carcinoma biomarker. Gold nanoparticles (Au NPs) functionalized magnetic multi-walled carbon nanotubes (MWCNTs-Fe3O4) were prepared and utilized for the adsorption of lead ions (Pb(2+)) and the secondary antibodies (Ab2). The resultant nanocomposites (Pb(2+)@Au@MWCNTs-Fe3O4) were used as the label for signal amplification, showing better electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) than MWCNTs, MWCNTs-Fe3O4 or Au@MWCNTs-Fe3O4 due to the synergetic effect presented in Pb(2+)@Au@MWCNTs-Fe3O4. Moreover, Au NPs were electrodeposited on the surface of glassy carbon electrode (GCE) for the effective immobilization of primary antibodies (Ab1). Under the optimal conditions, a linear range from 10 fg/mL to 100 ng/mL and a detection limit of 3.33 fg/mL were obtained. The proposed electrochemical sandwich-type immunosensor shows high sensitivity, good selectivity and stability for the quantitative detection of AFP, holding a great potential in clinical and diagnostic applications.
authors: School of Chemical Engineering, Shandong University of Technology, Zibo 255049, PR China.
authors: Faying
authors: F
authors: Li
authors: School of Chemical Engineering, Shandong University of Technology, Zibo 255049, PR China.
authors: Jian
authors: J
authors: Han
authors: School of Chemical Engineering, Shandong University of Technology, Zibo 255049, PR China.
authors: Liping
authors: L
authors: Jiang
authors: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors: Yulan
authors: Y
authors: Wang
authors: School of Chemical Engineering, Shandong University of Technology, Zibo 255049, PR China. Electronic address: liyueyun71@163.com.
authors: Yueyun
authors: Y
authors: Li
authors: School of Chemical Engineering, Shandong University of Technology, Zibo 255049, PR China.
authors: Yunhui
authors: Y
authors: Dong
authors: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors: Qin
authors: Q
authors: Wei
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D000509:alpha-Fetoproteins / Q000302:isolation & purification*
chemical_list: D055910:Antibodies, Immobilized; D037742:Nanotubes, Carbon; D000509:alpha-Fetoproteins; D006046:Gold; D006861:Hydrogen Peroxide
keywords: Alpha fetoprotein; Gold nanoparticles; Lead ions; Multi-walled carbon nanotubes; Sandwich-type immunosensor