Influence of the physical and chemical properties of magnetic nanoparticles on their performance in a chemiluminescence immunoassay

Objectives: Magnetic nanoparticles (MNPs) are important carriers in immunoassays. In this study, we investigated the influence of the physical and chemical properties of MNPs on their performance in a detection process. Design and methods: A comparative study of the properties of two MNPs with sizes of 200 nm and 1 mu m (MNP-200 nm and MNP-1 mu m, respectively) was conducted using the following four aspects: nonspecific adsorption to proteins (IgG was used as a model protein), influence of magnetic nanoparticles on the chemiluminescence signal, response speed to an external magnetic field, and intensity of the detection signal. Results: MNP-1 mu m exhibited lower nonspecific adsorption to IgG in serum, a weaker interference with the chemiluminescence signal, and a higher response speed to the external magnetic field than the same amount of MNP-200 nm. An automated chemiluminescence immunoassay system based on MNP-1 mu m was also established. Conclusions: MNP-1 mu m acts as an excellent carrier in an automated chemiluminescence immunoassay system for the analysis of serum samples from clinical patients. (C) 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.