title: Ratiometric ultrasensitive electrochemical immunosensor based on redox substrate and immunoprobe.
abstract: In this work, we presented a ratiometric electrochemical immunosensor based on redox substrate and immunoprobe. Carboxymethyl cellulose-Au-Pb2+(CMC-Au-Pb2+) and carbon-Au-Cu2+(C-Au-Cu2+) nanocomposites were firstly synthesized and implemented as redox substrate and immunoprobe with strong current signals at -0.45 V and 0.15 V, respectively. Human immunoglobulin G (IgG) was used as a model analyte to examine the analytical performance of the proposed method. The current signals of CMC-Au-Pb2+(Isubstrate) and C-Au-Cu2+(Iprobe) were monitored. The effect of redox substrate and immunoprobe behaved as a better linear relationship between Iprobe/Isubstrateand Lg CIgG(ng mL-1). By measuring the signal ratio Iprobe/Isubstrate, the sandwich immunosensor for IgG exhibited a wide linear range from 1 fg mL-1to 100 ng mL-1, which was two orders of magnitude higher than other previous works. The limit of detection reached 0.26 fg mL-1. Furthermore, for human serum samples, the results from this method were consistent with those of the enzyme linked immunosorbent assay (ELISA), demonstrating that the proposed immunoassay was of great potential in clinical diagnosis.
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China.
authors.forename: Zhongxue
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China.
authors.forename: Zhanfang
authors.initials: Z
authors.lastname: Ma
mesh_terms: D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods / Q000592:standards; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D007074:Immunoglobulin G / Q000097:blood*; D007854:Lead / Q000737:chemistry; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry; D010084:Oxidation-Reduction
chemical_list: D007074:Immunoglobulin G; D007854:Lead; D006046:Gold; D003300:Copper; D002266:Carboxymethylcellulose Sodium