Preparation of superparamagnetic iron oxide nanoparticles and investigation of their interaction with cells

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely studied in biomedical applications such as bioimaging through magnetic resonance imaging and drug delivery. The successful uses of SPIONs depend on nanoparticles stability in biological environment and their interactions with cells. Hence these two factors are crucial for improvement of nanoparticle design in these applications. In this work, SPIONs were synthesized with silica (S-SPIONs) and amine (A-SPIONs) surface modifications providing hydroxyl and amine functionalities, respectively. The colloidal stabilities of SPIONs were evaluated as hydrodynamic size in different biological relevance media. The results showed that bare SPIONs were unstable and highly aggregated when exposed to cell culture media. Coating with silica and amine could effectively stabilized the nanoparticles as evidenced by reduction of hydrodynamic diameters. In addition to surface modification, supplementation of serum proteins to cell culture media also reduced the aggregations. Furthermore, both S-SPIONs and A-SPIONs showed no cytotoxicity effect on human breast cancer cells (MCF-7) with cell viability remained over 80%. Hence this study showed the role of surface modification of bare SPIONs with silica and amine functionalization and serum supplement to stabilize nanoparticle stability in biological environment. These two surface coating SPIONs were not only non-toxic to the cells, but also have surface functionalities that could be further conjugated with desired biomolecules for more specific targeting especially in cancer targeting for diagnosis or therapeutic applications.