Influence of chitosan modification on self-assembly behavior of FeO nanoparticles

Self-assembled FeO 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 FeO 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 FeO nanoparticles. In this work, natural polysaccharide chitosan was used to modify FeO nanoparticles. The self-assembled FeO nanochains were obtained easily by controlling the ratio of chitosan and FeO nanoparticles. The formation mechanism of FeO 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 FeO nanoparticles. The prepared chitosan-modified FeO nanochains would be a promising candidate with good biocompatibility for biomedical applications.