Issue 8, 2018, Issue in Progress

Characterization of magnetic relaxation when biofunctionalized magnetic nano-particles are associated with biomarkers in the liquid state in biomedical applications

Abstract

This study determined the characteristics of the time-dependent effective relaxation time τeff and magnetization M when biofunctionalized magnetic nanoparticles (BMNPs) associated with biomarkers in a liquid immunoassay. Carcinoembryonic antigen (CEA) was used as the biomarker. BMNP is an anti-CEA that was coated onto dextran-coated Fe3O4 and labeled as Fe3O4-anti-CEA. The phase lag θ of M with respect to the applied field H was measured using a sensitive homemade alternative-current susceptometer, and θ was measured using lock-in detection. The results were used to estimate τeff using the relationship tan θ(t) = ωτeff(t), where 2πf = ω and f is the excitation frequency. Δτeff increased with ΦCEA, where Δτeff was the increment of τeff after Fe3O4-anti-CEA associated with CEA, and ΦCEA was the concentration of CEA. Additionally, M enhanced when ΦCEA increased. We attributed these enhancements to magnetic dipole–dipole interactions among MNPs that contributed extra M and in turn enhanced τeff. Magnetic clusters after the association were verified using a transmission electron microscope. This study established the relationship between Δτeff/τeff,0 and ΦCEA, where τeff,0 = τeff (ΦCEA = 0), allowing the assay of an unknown amount of CEA molecules.

Graphical abstract: Characterization of magnetic relaxation when biofunctionalized magnetic nano-particles are associated with biomarkers in the liquid state in biomedical applications

Article information

Article type
Paper
Submitted
21 Nov 2017
Accepted
15 Jan 2018
First published
23 Jan 2018
This article is Open Access
Creative Commons BY license

RSC Adv., 2018,8, 4057-4062

Characterization of magnetic relaxation when biofunctionalized magnetic nano-particles are associated with biomarkers in the liquid state in biomedical applications

S. Liao, H. Huang, J. Chen, Y. Su and Y. Tong, RSC Adv., 2018, 8, 4057 DOI: 10.1039/C7RA12634D

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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