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Updated: Feb 26, 2026
A Method for Selecting Structure-switching Aptamers Applied to a Colorimetric Gold Nanoparticle Assay
Published on: February 28, 2015
An enzyme-mediated competitive colorimetric sensor based on Au@Ag bimetallic nanoparticles for highly sensitive
Binfeng Yin1, Wenshu Zheng, Mingling Dong
1Beijing Engineering Research Center for BioNanotechnology and CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for NanoScience and Technology, Beijing 100190, P. R. China. chenyp@nanoctr.cn xingyujiang@nanoctr.cn.
Abstract:
We developed a competitive colorimetric nanosensor based on Au@Ag bimetallic nanoparticles for the detection of interleukin-6 (IL-6) in clinical samples. Antibody-conjugated magnetic nanoparticles (MNPs) and polystyrene (PS) microparticles conjugated with both catalase and a secondary antibody can form sandwich structures that enable one-step target enrichment and separation. The catalase on the surface of the PS can catalyze the hydrolysis of hydrogen peroxide (H2O2) to regulate the deposition of Ag+ on the surface of gold nanoparticles (AuNPs), and forms different sizes and amounts of Au@Ag bimetallic nanoparticles (Au@AgNPs) which produce a distinct color signal for readout with the naked eye. Our sensor features high sensitivity, selectivity, reproducibility and anti-interference property as a result of comprehensive parameter optimization. The limit of detection of IL-6 can reach 11 pg mL-1 with the naked eye and 1.2 pg mL-1 by quantitative instrumental analysis. The whole analysis can be finished within 1 h. More importantly, we successfully apply our platform or the detection of IL-6 in clinical samples with better accuracy than conventional enzyme-linked immunosorbent assay (ELISA).
