Influence of chitosan modification on self-assembly behavior of Fe3O4 nanoparticles.

Self-assembled Fe₃O₄ nanoparticles are attracting more and more interests in biomedical field, such as dual photoacoustic devices and magnetic resonance imaging. At present, however, the preparation of self-assembled Fe₃O₄ nanoparticles mainly relies on the modifications of some toxic polymers, such as 4-vinylpyridine, polyacrylonitrile, and phenol formaldehyde resin. Additionally, the synthetic methods used were too complicated. The biological toxicity and complex methods significantly limit the biomedical applications of self-assembled Fe₃O₄ nanoparticles. In this work, natural polysaccharide chitosan was used to modify Fe₃O₄ nanoparticles. The self-assembled Fe₃O₄ nanochains were obtained easily by controlling the ratio of chitosan and Fe₃O₄ nanoparticles. The formation mechanism of Fe₃O₄ nanochains was proposed and demonstrated by experiments and numerical simulation. It is found that the thickness of chitosan is a key factor that affects the magnetic field distributions and magnetic attraction of Fe₃O₄ nanoparticles. The prepared chitosan-modified Fe₃O₄ nanochains would be a promising candidate with good biocompatibility for biomedical applications. [ABSTRACT FROM AUTHOR]