Multilayer hemin/G-quadruplex wrapped gold nanoparticles as tag for ultrasensitive multiplex immunoassay by chemiluminescence imaging.

Abstract

A multilayer hemin/G-quadruplex DNAzyme wrapped gold nanoparticle (M-DNAzyme/AuNP) tag was designed for ultrasensitive chemiluminescence (CL) imaging. By combining with a disposable protein array, an ultrasensitive and high-throughput multiplex CL immunoassay method was proposed for simultaneous detection of four cancer biomarkers. The M-DNAzyme/AuNP tag was prepared by assembling high ratio of alkylthiol-capped signal DNA containing multiple G-quadruplex sequences to biotinylated DNA on AuNPs and then reacting with hemin to form multilayer hemin/G-quadruplex DNAzyme units. It could be bound to the biotinylated secondary antibody of sandwich immunocomplex by biotin-streptavidin conjugation to catalyze a CL reaction on a protein array, which produced strong CL emission. Under optimal conditions, the CL signals could be simultaneously collected by a charge-coupled device for ultrasensitive multiplex CL imaging of cancer biomarkers. Using α-fetoprotein, human chorionic gonadotrophin-β, carcinoma antigen 125, and carcinoembryonic antigen as model analytes, the proposed immunoassay method showed high sensitivities and wide linear ranges in a simple, cheap and high throughput way. The M-DNAzyme/AuNP as a universal signal tag as well as the protein chip could be suitable for mass production for economical, portable and multianalyte assay, showing a promising potential in application to clinic and other relative fields.

• Authors: Chen Zong, Jie Wu, Jie Xu, Huangxian Ju, Feng Yan
• Journal: Biosensors & bioelectronics (Biosens Bioelectron) Vol. 43 Pg. 372-8 (May 15 2013) ISSN: 1873-4235 [Electronic] England
• PMID: 23356995 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Elsevier B.V. All rights reserved.

Chemical References

• Biomarkers, Tumor
• DNA, Catalytic
• Hemin
• Gold

Topics

• Biomarkers, Tumor (analysis)
• Biosensing Techniques (instrumentation)
• DNA, Catalytic (chemistry)
• Equipment Design
• Equipment Failure Analysis
• G-Quadruplexes
• Gold (chemistry)
• Hemin (chemistry)
• Humans
• Immunoassay (instrumentation)
• Luminescent Measurements (instrumentation)
• Metal Nanoparticles (analysis)