title: Amperometric immunosensor for carbofuran detection based on MWCNTs/GS-PEI-Au and AuNPs-antibody conjugate.
abstract: In this paper, an amperometric immunosensor for the detection of carbofuran was developed. Firstly, multiwall carbon nanotubes (MWCNTs) and graphene sheets-ethyleneimine polymer-Au (GS-PEI-Au) nanocomposites were modified onto the surface of a glass carbon electrode (GCE) via self-assembly. The nanocomposites can increase the surface area of the GCE to capture a large amount of antibody, as well as produce a synergistic effect in the electrochemical performance. Then the modified electrode was coated with gold nanoparticles-antibody conjugate (AuNPs-Ab) and blocked with BSA. The monoclonal antibody against carbofuran was covalently immobilized on the AuNPs with glutathione as a spacer arm. The morphologies of the GS-PEI-Au nanocomposites and the fabrication process of the immunosensor were characterized by X-ray diffraction (XRD), ultraviolet and visible absorption spectroscopy (UV-vis) and scanning electron microscopy (SEM), respectively. Under optimal conditions, the immunosensor showed a wide linear range, from 0.5 to 500 ng/mL, with a detection limit of 0.03 ng/mL (S/N = 3). The as-constructed immunosensor exhibited notable performance features such as high specificity, good reproducibility, acceptable stability and regeneration performance. The results are mainly due to the excellent properties of MWCNTs, GS-PEI-Au nanocomposites and the covalent immobilization of Ab with free hapten binding sites for further immunoreaction. It provides a new avenue for amperometric immunosensor fabrication.
authors.affiliation: School of Agriculture and Food Engineering, Shandong University of Technology, Zibo 255049, China. zy_881120@126.com
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhu
authors.forename: Yaoyao
authors.initials: Y
authors.lastname: Cao
authors.forename: Xia
authors.initials: X
authors.lastname: Sun
authors.forename: Xiangyou
authors.initials: X
authors.lastname: Wang
mesh_terms: D000906:Antibodies / Q000378:metabolism*; D015374:Biosensing Techniques / Q000295:instrumentation*; D002235:Carbofuran / Q000032:analysis*; D055664:Electrochemical Techniques / Q000295:instrumentation*; D005638:Fruit / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000648:ultrastructure; D053761:Nanocomposites / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D011094:Polyethyleneimine / Q000737:chemistry*; D015203:Reproducibility of Results; D014675:Vegetables / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000906:Antibodies; D037742:Nanotubes, Carbon; D006046:Gold; D006108:Graphite; D011094:Polyethyleneimine; D002235:Carbofuran