RESUMEN
A novel flexible electrospun nanofiber/γ-Fe2O3 composite has been obtained from suspension of γ-Fe2O3 nanoparticles in polyvinylpyrolidone solution in dimethylformamide. The impedance spectroscopy of the synthesized nanofiber/γ-Fe2O3 composite was carried out. Negative magnetoresistance and giant magnetocapacitance effects, as well as phenomenon of a "negative capacitance" at room temperature were observed in magnetic field (2.75 κOe) in infra-low frequency range. The polarization properties and volt-ampere characteristics of the nanocomposite in the applied magnetic field indicate the increase in the dielectric permittivity É and the emergence of spin electromotive force, which enables us to accumulate of electric energy at quantum level. A quantum-mechanical model, which explained the non-monotonous behaviour of the volt-ampere characteristic of the novel nanofiber based composite, has been suggested.
RESUMEN
Colloidal-chemical characteristics of block/branched cationic and non-ionic polyamphiphiles containing poly(fluorine-alkyl methacrylate) (poly(FMA)) block and their intermolecular complexes with biopolymers were studied. The dependences of their surface activity and micelle size on the length of hydrophobic and hydrophilic blocks, as well as the length of side fluorine-alkyl branches were established. Poly(FMA)-block-poly(DMAEMA) was used for formation of interpolyelectrolyte complexes with plasmid DNA (pDNA) via their electrostatic interaction. Novel non-viral polyplexes were tested as gene delivery systems for mammalian cells. The results of DLS, TEM and MALDI-ToF studies demonstrated disaggregation of lysozyme (LYZ) aggregates in the presence of poly(FMA)-block-poly(NVP) and formation of the polyamphiphile LYS complex possessing antibacterial action.