In Vitro Safety Evaluation and In Vivo Imaging Studies of Superparamagnetic Iron Oxide Nanoparticles through Biomimetic Modification

Magnetic resonance imaging (MRI) is an advanced medical imaging diagnostic technique that utilizes different resonance signals generated by the signal strength of water content and the relaxation time of protons in water molecules under the influence of an external magnetic field. This technique requires contrast agents, such as Gd-DTPA and Gd-DOTA, which could increase the risk of renal fibrosis in patients with severe renal insufficiency. The magnetic moment or susceptibility of superparamagnetic iron oxide nanoparticle (SPION) is higher than that of other paramagnetic substances and could significantly reduce the dosage of the contrast agent required. In our previous work, the novel magnetic composite nanoparticles (abbreviated as c(RGDyK)-PDA-SPION) had been successfully synthesized by a facile and simple approach. Further evaluation had demonstrated that it had an average particle size of about 50 nm and uniform distribution, superparamagnetic properties, and good dispersion stability in water solution. Animal acute toxicity test also had proved that it had high safety in vivo. In this work, c(RGDyK)-PDA-SPION was further studied for the cell toxicity and effect on HepG2 cells in vitro, and the MRI imaging of this contrast agent in HepG2 tumor-bearing mice was also studied. It is an extension of the published work. The results showed that it possessed high safety and enrichment phenomenon on HepG2 cells in vitro. Animal experimental data preliminarily prove that the contrast agent could enhance the MRI T2 -weighted imaging capability of HepG2 carcinoma in tumor-bearing mice and could be a potential T2 contrast agent.