title: Multiplexed electrochemical immunoassay of biomarkers using chitosan nanocomposites.
abstract: In this work, a novel and sensitive multiplexed immunoassay protocol for simultaneous electrochemical determination of alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) was designed using functionalized chitosan composites. The immunosensing platform was prepared via immobilizing capture anti-AFP and anti-CEA on chitosan-Au nanoparticles (AuNPs) through EDC/NHS linking. The signal tags were fabricated by immobilizing electroactive redox probes - Prussian blue (PB) and ferrocenecarboxylic acid (Fc) on chitosan (CHIT), following by absorbing AuNPs to immobilize labeled anti-AFP and anti-CEA, respectively. A sandwich-type immunoassay format was employed for the simultaneous detection of AFP and CEA. The assay was based on the electrochemical oxidation/reduction of the redox species in signal tags, which has a relationship with the concentration of analytes. Experimental results revealed that the multiplexed electrochemical immunoassay enabled the simultaneous monitoring of AFP and CEA with a wide range of 0.05-100 ng mL(-1) for both AFP and CEA. The detection limits (LOD) was 0.03 ng mL(-1) for AFP and 0.02 ng mL(-1) for CEA (S/N=3). The assay results of serum samples with the proposed method were in a good agreement with the reference values from standard ELISA method. And the negligible cross-reactivity between the two analytes makes it possesses potential promise in clinical diagnosis.
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China. Electronic address: mazhanfang@cnu.edu.cn.
authors.forename: Zhanfang
authors.initials: Z
authors.lastname: Ma
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis* / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation*; D002272:Carcinoembryonic Antigen / Q000032:analysis* / Q000276:immunology; D048271:Chitosan / Q000737:chemistry*; D045424:Complex Mixtures / Q000032:analysis / Q000276:immunology; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D045424:Complex Mixtures; D048271:Chitosan
keywords: Alpha-fetoprotein; Carcinoembryonic antigen; Chitosan-Au nanoparticles; Chitosan-Prussian blue-Au nanoparticles; Chitosan-ferrocenecarboxylic acid-Au nanoparticles