Functionalization of iron oxide magnetic nanoparticles with targeting ligands: Their physicochemical properties and in vivo behavior

Aim: To develop and evaluate two tumor-specific nanoprobes by functionalization of a polyethylene glycol-immobilized nanoparticle with arginine-glycine-aspartic acid (RGD) or chlorotoxin ligand that targets α_vβ₃ integrin and matrix metalloproteinase-2 receptors, respectively. Materials & methods: The nanoprobes were made of iron oxide cores, biocompatible polymer coating, and surface-conjugated RGD or chlorotoxin peptide. The tumor-targeting specificity of the nanoprobes was evaluated both in vitro and in vivo. Results & discussion: Both nanoprobes were highly dispersive and exhibited excellent long-term stability in cell culture media. The RGD-conjugated nanoprobe displayed a strong initial accumulation near neovasculatures in tumors followed by quick clearance. Conversely, the chlorotoxin-enabled nanoprobe exhibited sustained accumulation throughout the tumor. Conclusion: These findings revealed the influence of the targeting ligands on the intratumoral distribution of the ligand-enabled nanoprobes. With flexible surface chemistry, our nanoparticle platform can be used in a modular fashion to conjugate biomolecules for intended applications.