Structure and magnetic properties of the ZnxMg1-xFe2O4ferrites

Stealth Magnetoliposomes Based on Calcium-Substituted Magnesium Ferrite Nanoparticles for Curcumin Transport and Release

Despite the promising pharmacological properties of curcumin, the transport and effective release of curcumin is still a challenge. The advances in functionalized nanocarriers for curcumin have also been motivated by the anticancer activity of this natural compound, aiming at targeted therapies. Here, stealth (aqueous and solid) magnetoliposomes containing calcium-substituted magnesium ferrite nanoparticles, Ca_xMg_1−xFe₂O₄ (with x = 0.25, 0.50, 0.75) were developed as nanocarriers for curcumin. The magnetic nanoparticles exhibit superparamagnetic properties and crystalline structure, with sizes below 10 nm. The magnetoliposomes based on these nanoparticles have hydrodynamic diameters around or below 150 nm and a low polydispersity. The influence of an alternating magnetic field (AMF) on drug release over time was evaluated and compared with curcumin release by diffusion. The results suggest the potential of drug-loaded magnetoliposomes as nanocarriers that can be magnetically guided to the tumor sites and act as agents for a synergistic effect combining magnetic hyperthermia and controlled drug release.

Tetracycline-ferrite nanocomposites formed via high-energy ball milling and the influence of milling conditions

High-energy ball milling was used to mediate the formation of nanocomposites containing tetracycline and magnetic nanoparticles. Tetracycline-HCl was ball milled for 1, 3, 5, 15, and 30 h under argon or air atmosphere with preformed Mg 0.5 Zn 0.5 Fe2O4 nanoferrites prepared by glycolthermal method. The structural, thermal, and magnetic properties of these novel materials and the effect of milling atmosphere on composition, crystallinity and cation distribution were then characterized by ICP-OES, DSC/TGA, XRPD, ATR-IR, UV-Vis and Mössbauer spectroscopy. Tetracycline underwent rapid and consecutive metal coordination events in the milling process to yield complexes characterized by bathochromic shifts in its electronic spectra and suppression of electronic absorbance at 365 nm. Changes in stretching vibrations due to the A-ring carbonyl (1616 cm(-1)), amide II nitrogen (1602 cm(-1)), and CO bond (1039 cm(-1)) indicate Mg-type interactions imposed on the metals. Exothermic oxidation of the drug at 235°C disappeared after 5h milling with the nanoferrites, and the composites formed remained thermostable up to 500°C. Tetracycline-nanoferrites (Tet-NF) are magnetic-ordered materials with a well-defined spinel-type structure. Analysis of the Mössbauer data suggests that the milling time and atmosphere have significant influence on cation distributions in Tet-NF composites.