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Updated: Feb 11, 2026

Rapid Homogeneous Detection of Biological Assays Using Magnetic Modulation Biosensing System
Published on: June 13, 2010
Cascade Reaction-Mediated Assembly of Magnetic/Silver Nanoparticles for Amplified Magnetic Biosensing
Yiping Chen1, Yunlei Xianyu1, Mingling Dong1,2
1Beijing Engineering Research Center for BioNanotechnology and CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience , National Center for NanoScience and Technology , No. 11 Zhongguancun Beiyitiao , Beijing 100190 , P. R. China.
Abstract:
Conventional magnetic relaxation switching (MRS) sensor suffers from its relatively low sensitivity when it comes to the analysis of trace small molecules in complicated samples. To meet this challenge, we develop a cascade reaction-mediated magnetic relaxation switching (CR-MRS) sensor, based on the assembly of silver nanoparticles (Ag NPs) and magnetic nanoparticles (MNPs) to improve the sensitivity of conventional MRS. The cascade reaction triggered by alkaline phosphatase generates ascorbic acid, which reduces Ag+ to Ag NPs that can assemble the initially dispersed MNPs to form magnetic/silver nanoassemblies, thus modulating the state of MNPs to result in the change of transverse relaxation time. The formed magnetic/silver nanoassemblies can greatly enhance the state change of MNPs (from dispersed to aggregated) and dramatically improve the sensitivity of traditional MRS sensor, which makes this CR-MRS sensor a promising platform for highly sensitive detection of small molecules in complicated samples.
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