Mina Sakuragi

Structural and biological characterization of Fe3O4-loaded spherical and tubular liposomes for use in drug delivery systems

Magnetic liposomes containing Fe3O4 nanoparticles were prepared using colipids [1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC8,9PC)] and mixtures of the colipids with an anionic lipid [1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG)] or a cationic lipid [cetyltrimethylammonium bromide (CTAB)]. Transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) analysis showed that the magnetic liposomes containing DC8,9PC and DOPC were tubular and spherical in structure, respectively. The effects of an external magnetic field and the structure of the liposomes on cellular association were investigated. The external magnetic field increased cellular association and uptake levels independent of the structure both in vitro and in vivo. Although the level of in vitro cellular association for the tubular liposomes was higher than that for the spherical liposomes, there was no significant difference in the level of in vivo uptake of fluorescent Fe3O4 nanoparticles in the mouse liver. Finally, the magnetic liposomes were found to be biocompatible by haematological and serum chemical analyses.

Deep Eutectic Solvent-Induced Structural Transition of Microemulsions Explored with Small-Angle X-ray Scattering

Microemulsions (MEs) containing deep eutectic solvents (DESs) and water in the inner phase for use in transdermal delivery of poorly soluble drugs were prepared using a mixture of polyoxyethylene sorbitan monooleate (Tween-80) and sorbitan laurate (Span-20) as surfactants. We investigated the effects of the ratios of surfactant (Tween-80/Span-20) and solvents (DES components/water) on the ME structure determined by the analysis of small-angle X-ray scattering profiles with the core-corona model. Tween-80 with an unsaturated long alkyl chain induced a structural transition of MEs from a sphere to a cylinder. DESs caused the aggregation of surfactants due to the solvophobic interactions between DESs and the alkyl chains of surfactants. Transmittance electron microscopy images of MEs indicated the presence of aggregates of the dispersed ME particles with each shape.