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Antoniya Toncheva,Iliya Rashkov,Dilyana Paneva,Nevena Manolova 한국고분자학회 2011 Macromolecular Research Vol.19 No.12
Micro- and nanofibrous electrospun poly(L-lactide) (PLA) and PLA/poly(ethylene glycol) (PEG)membranes containing diclofenac sodium (DS), lidocaine hydrochloride (LHC), benzalkonium chloride (BC), or combinations thereof (DS/LHC and DS/LHC/BC) have been developed. The addition of low molecular weight organic salts to the spinning PLA and PLA/PEG solutions results in increased conductivity and contributes to the preparation of membranes composed of fibers that are well-aligned with the collector rotation direction. The water contact angle values of the PLA and PLA/PEG membranes are characteristic of hydrophobic surfaces. The incorporation of LHC in the fibers does not lead to membrane hydrophilization. In contrast to LHC, other drugs or combinations thereof have led to the preparation of hydrophilic fibrous materials. The hydrophilization is due to the presence of DS or BC fragments or functional groups on the fibrous membrane surfaces as verified by Xray photoelectron spectroscopy (XPS). As evidenced by the differential scanning calorimetric study and X-ray diffraction analysis data, the drugs incorporated in the fibers are in the amorphous state. The release profiles of DS, LHC, and BC from the PLA/drug and PLA/PEG/drug fibrous membranes depend on the drug nature and, in the case of BC, on the composition of the polymer scaffold as well. The release of DS and LHC from the PLA/DS/LHC and PLA/PEG/DS/LHC membranes is slower compared to that of the single drug-loaded membranes. This phenomenon has been attributed to an ionic interaction between the two drugs. Microbiological studies have demonstrated that the PLA/DS, PLA/BC, PLA/DS/LHC, and PLA/DS/LHC/BC membranes exhibit antibacterial activity against Staphylococcus aureus.
Thermal Imidization Peculiarities of Electrospun BPDA-PDA/ODA Copolyamic Acid Nanofibers
Laura Peciulyte,Ramune Rutkaite,Algirdas Zemaitaitis,Milena Ignatova,Iliya Rashkov,Nevena Manolova 한국고분자학회 2013 Macromolecular Research Vol.21 No.4
Copolyamic acid (coPAA) based on 4,4'-oxydianiline (ODA), p-phenylenediamine (PDA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was synthesized in N,N-dimethylformamide (DMF). The preparation of continuous defect-free nanofibers from BPDA-PDA/ODA coPAA was achieved by electrospinning of its DMF solution. The average fiber diameter significantly increased from 385 to 590 nm on increasing the total polymer concentration of the spinning solutions from 5 to 7 wt%. The addition of dodecylethyldimethylammonium bromide (DEDAB) salt to the spinning solution resulted in the procurement of coPAA nanofibers with a much smaller (more than 3 times) average diameter. The coPAA imidization process was investigated through FTIR spectroscopy. The chemical composition and morphology of coPI nanofibers were assessed by X-ray photoelectron spectroscopy and scanning electron microscopy. Imidization under isothermal conditions proceeded faster in the first stage. Activation energies in the first and second imidization stages were similar when DEDAB had been added into the electrospinning solution. Cylindrical or crimped defect-free nanofibers of BPDA-PDA/ODA copolyimide (coPI) were obtained by the stepped thermal imidization of coPAA. The morphology of coPI nanofibers depends on the curing temperature. The crimped coPI nanofibers were most probably due to the relief of residual stress when the curing temperature was higher than the polymer glass transition temperature.
Curcumin-PVP Loaded Electrospun Membranes with Conferred Antibacterial and Antitumoral Activities
Gyuldzhan Yakub,Antoniya Toncheva,Veselin Kussovski,Reneta Toshkova,Ani Georgieva,Elena Nikolova,Nevena Manolova,Iliya Rashkov 한국섬유공학회 2020 Fibers and polymers Vol.21 No.1
Electrospun membranes containing curcumin were prepared from poly(L-co-D,L-lactic) acid and polyvinylpyrrolidone. The effect of curcumin concentration on the solution viscosity and the morphology of fiber was studied. Curcumin solubility in aqueous solutions was enhanced by the formation of curcumin/polyvinylpyrrolidone watersoluble complex. Curcumin physico-chemical and therapeutic properties within the membranes were preserved upon UV-Vislight irradiation, as a part of the membranes sterilization. The biomaterials showed antibacterial activity against pathogenic microorganisms such as Staphylococcus aureus and Candida albicans. In-vitro experiments against HeLa and Graffi tumor cells and white blood cells (peritoneal macrophages and spleen lymphocytes) revealed potential biomedical application of the membranes.
Ecaterina Stela Dragan,Marcela Mihai,Gabriela Hitruc,Dilyana Paneva,Nevena Manolova,Iliya Rashkov 한국고분자학회 2011 Macromolecular Research Vol.19 No.10
Composite multilayer thin films have been constructed on planar substrates by the layer-by-layer deposition of chitosan (CS) and two strong polyanions different by the density of sulfonic groups, i.e., poly(sodium 2-acrylamido-2-methylpropanesulfonate) (PAMPS) and a random copolymer of AMPS with acrylic acid, P(AMPS_55-co-AA_45); all deposition steps being performed at pH 5.5. The effect of the polyanion structure and number of adsorbed layers on the film morphology was examined by atomic force microscopy and contact angle measurements. The polyanion structure strongly affected the multilayer morphology, more swollen and less dense films being formed when P(AMPS_55-co-AA_45) was used compared to PAMPS. The sorption of two proteins, human serum albumin and bovine serum albumin, on the film surface with CS as the last layer adsorbed, as a function of the polyanion structure,indicates that a higher amount of protein had been sorbed mainly on the film surface when PAMPS was used as a polyanion in the film construction.