title: Displacement-type amperometric immunosensing platform for sensitive determination of tumour markers.
abstract: The sensitive determination of carcino embryonie antigen (CEA)-a set of highly related glycoproteins involved in cell adhesion-is beneficial to the early diagnosis of colorectal cancer. In this study, a novel displacement-type amperometric immunosensing platform, based on the fact that glucose and Alizarin Red S (ARS) compete for phenylboronic acid bindng sites, was projected for sensitive detection of tumour marker (CEA, used as a model) on a PAMAM dendrimer-encapsulated nanogold (PAMAM-Au)-functionlized sensing interface. Firstly, 4(-)mercaptophenylboronic acid (S-PBA) was assembled onto the PAMAM-Au via the S-Au interaction, and then ARS was immobilized by S-PBA binding of cis-diol moieties, which was dropped on the surface of glassy carbon electrode as sensing platform to combine antibody. Meanwhile, amylase modified gold nanoparticles were employed as labels. Accompanying the sandwich immunoassay, the carried amylase could hydrolyze amylose into glucose, and the displacement-type format was triggered due to the stronger adhesion between glucose and PBA, which resulted in the change of electrochemical signals due to the decrease of ARS (as an electron mediator). Under optimal conditions, the SWV signals were related to the concentration of CEA, indicating a certain proportional relation in a range of 0.01~50ngmL(-1) with a detection limit (LOD) of 0.003ngmL(-1). Intra- and inter-assay coefficients of variation were below 10%, respectively. In addition, the methodology showed good accordance with a commercialized enzyme-linked immunosorbent assay (ELISA) method.
authors.affiliation: College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, PR China. Electronic address: zhangbing01@tyut.edu.cn.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, PR China.
authors.forename: Chuanmin
authors.initials: C
authors.lastname: Ding
mesh_terms: D000880:Anthraquinones / Q000737:chemistry; D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood; D015374:Biosensing Techniques / Q000379:methods; D001897:Boronic Acids / Q000737:chemistry; D002272:Carcinoembryonic Antigen / Q000032:analysis / Q000097:blood*; D004396:Coloring Agents / Q000737:chemistry; D050091:Dendrimers / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D005947:Glucose / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D049329:Nanostructures / Q000737:chemistry
chemical_list: D000880:Anthraquinones; D014408:Biomarkers, Tumor; D001897:Boronic Acids; D002272:Carcinoembryonic Antigen; D004396:Coloring Agents; D050091:Dendrimers; C104700:PAMAM Starburst; C004468:Alizarin Red S; D006046:Gold; D005947:Glucose; C010686:benzeneboronic acid
keywords: Alizarin Red S; Carcino Embryonie antigen; Displacement; Electrochemical Immunosensor; Glucose; Phenylboronic acid