Nanocomposite biomimetic vesicles based on interfacial complexes of polyelectrolytes and colloid magnetic nanoparticles

Development and study of novel biomimetic and biocompatible functional nanofilm structures, surfaces and colloid membranous vesicles are currently important from fundamental and applied viewpoints. They can serve as model systems for insight into the basic structural-functional interconnections and physicochemical mechanisms at the nano-scale in biomembranous systems, and are useful for development of engineering solutions efficient for bio-medical applications including controlled drug delivery. We present here the results of a study of novel nanofilm composite structures (Langmuir monolayers, Langmuir-Blodgett films and liposomes) based on the interfacial complexes formed by biogenic lipid phosphatidylcholine, synthetic amphiphilic water-insoluble polyamine stearoylspermine (a derivative of biogenic polyamine spermine and stearic acid), colloid cationic ligand-free magnetite nanoparticles and polyanions (DNA, Poly(styrenesulfonate)). It was found that stearoylspermine molecules formed stable Langmuir monolayer on an aqueous subphase surface and that monolayer compression isotherm changed as a result of interactions of the stearoylspermine monolayer with aqueous subphase components (colloid cationic magnetite nanoparticles and polyanions). Monolayer Langmuir-Blodgett films of interfacial polycomplexes formed by stearoylspermine and magnetite nanoparticles or DNA molecules were deposited onto the mica substrate surface and the structure of polycomplex films was investigated using AFM. The data obtained using Langmuir monolayer technique were further used in formation of new composite nanofilm magnetic colloidal membranous vesicles based on the interfacial polycomplexes of phosphatidylcholine, stearoylspermine, magnetite nanoparticles and polyanions. The nanocomposite membranous vesicles were prepared successfully by sequential adsorption of colloid cationic ligand-free magnetite nanoparticles and polyanions onto the cationic surface of mixed phosphatidylcholine/stearoylspermine liposomes preliminarily formed using conventional ultrasound method. The formed vesicles were characterized by transmission electron microscopy, AFM, electron magnetic resonance technique, laser light scattering and electrophoresis techniques. The synthesized stable biocompatible nanocomposite magnetic liposomal vesicles can be useful in development of novel efficient systems for capsulation, targeted transport, controlled spatial localization and physical stimuli-addressed drug and DNA delivery.