Synthesizing and Optimizing Rutile TiO₂ Nanoparticles for Magnetically Guided Drug Delivery

Titanium dioxide nanoparticles (TiO₂ NPs) have shown tremendous potential in targeted drug-delivery applications. Among various mechanisms, magnetically guided transport of drugs is one such technique for the said purpose. TiO₂ NPs being diamagnetic or sometimes exhibiting very weak ferromagnetism can be modified by treating them with suitable magnetic materials.

Rutile TiO₂ NPs were synthesized and doped with Iron Supplement FericipXT and rare-earth metals like cerium, erbium and neodymium via sol-gel technique. FericipXT-coated rutile TiO₂ NPs were synthesized in three different core-shell ratios (1:3, 1:1 and 3:1). The resulting samples were characterized via X-ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM) and High-Resolution Transmission Electron Microscopy (HR-TEM).

XRD of FericipXT-doped TiO₂ NPs showed a rutile phase for 1% and 3% doping; however, only a small fraction of the maghemite phase was obtained for 5% doping. The XRD plots of Ce-doped, Er-doped and Nd-doped TiO₂ NPs showed a variety of phases of TiO₂ NPs (such as anatase/rutile/mixed) along with the oxide phases of the corresponding rare-earth metal. The presence of various iron titanium oxides and iron oxides was found in core-shell NPs. HR-TEM images confirmed the formation of 1:3, 1:1 and 3:1 core-shell TiO₂ NPs. VSM studies showed that the resulting NPs depicted magnetism in the form of superparamagnetism, ferromagnetism and even paramagnetism.

The doping to 3% does not affect the original phase of the resulting TiO₂ NPs as depicted from the XRD; however, a doping of 5% and more resulted in extra phases corresponding to the dopant added. FericipXT was loaded over TiO₂ NPs in amorphous form. Among all the samples synthesized, FericipXT-coated TiO₂ NPs demonstrated the best magnetic ability. It was deduced that coating with a magnetic material drastically improves the magnetic character of the host NPs.