Amino acid-capped transition metal ion-doped iron oxide nanoparticles: evaluating drug delivery carrier efficiency and in vitro magnetic resonance image contrasting ability

L-arginine capped and transition metal-doped Ultra-Small Iron Oxide Nanoparticles (USIONs) were synthesized by a wet chemical method. The nanoparticles (NPs) were encapsulated with Pluronic F127((R)) and used as a vehicle (M2+/Fe3O4@L-Arg/P) to load anti-cancer drug. The interaction of ligand molecules with NPs surface was studied by FTIR spectroscopy, while the Vibrating Sample Magnetometry and Mossbauer spectroscopy were used for magnetic properties. In vitro, drug release kinetics showed that Mn2+/Fe3O4@L-Arg/P/bg release 30% drug initially within 5 h and the next 20% in 72 h with an overall 50% release in three days. Approximately, 70% drug was released from Ni2+/Fe3O4@L-Arg/P/bg. The Mn2+/Fe3O4@L-Arg/P/bg took a long time to 70% release rate than Zn2+ and Ni2+-doped vehicles. M2+/Fe3O4@L-Arg/P/bg with 10 mu g/mL dosage can reduce the cell viability to 53, 31, and 94 for Zn2+, Mn2+, and Ni2+, respectively. Contrasting ability of the material was evaluated for Magnetic Resonance Imaging (MRI). The results indicate a shift from inherent T-2 to T-1 contrasting with a lower concentration. The parameters (like t(M,)t(R,)q, etc.) used in Solomon-Bloembergen-Morgan (SBM) theory for paramagnetic relaxation also be applicable to Fe3O4-based NPs system in terms of H-bonding to modulate the T-1 contrasting in MRI. [Graphical Abstract]

Automated summary

L-arginine capped and transition metal-doped Ultra-Small Iron Oxide Nanoparticles (USIONs) were synthesized and encapsulated with Pluronic F127((R)) as a drug delivery vehicle. The drug release kinetics showed significant release in 5 hours and 72 hours, with different release rates for different metal-doped vehicles. The nanoparticles exhibited contrasting ability for Magnetic Resonance Imaging (MRI), with a shift from T-2 to T-1 contrasting at lower concentrations.