Formulation and evaluation of anise-based bioadhesive vaginal gels.

Various formulations of anise-based bioadhesive gels are prepared. Freeze-drying method was successfully employed and superporous scaffolds were obtained. The resulting porous microarchitectures are strongly influenced by the composition of hydrogel formulations and temperature of freezing. Anise-based hydrogels frozen in liquid nitrogen and lyophilized generate regular assembly of polyhedral pores. For Carbopol 934-based hydrogels it was determined G'>G'' for whole tested strain amplitude range indicating solid-like behaviour due to their dense network and entanglement and interaction through hydrogen bonds and van-der Waals forces. For sodium alginate-based hydrogels it was determined G''>G' for whole tested strain amplitude range accompanied by the extended linear viscoelastic region indicating liquid-like behaviour due to the formation of a stable "pseudo-gel" structure. Biocompatibility features of tested hydrogels were evaluated by contact angle measurements and determination of surface tension parameters. It was found that all anise-based hydrogel formulations manifest modest activity against S. aureus and S. lutea and no activity against tested Gram negative bacteria. Carbopol 934-based hydrogels containing anise exhibit antifungal activity against C. albicans, C. glabrata and C. Parapsilosis.

Imino-chitosan biopolymeric films. Obtaining, self-assembling, surface and antimicrobial properties.

The paper reports the preparation of twelve imino-chitosan biopolymer films by acid condensation of the amino groups of chitosan with various aldehydes, in aqueous medium, followed by slow water removal. FTIR spectroscopy has shown drastic conformation changes of chitosan macromolecular chains­from a stiff coil to a straight one, while wide angle X-ray diffraction evidenced a layered morphology of the biopolymer films. Contact angle and surface free energy determination indicated a higher biocompatibility of the new biopolymers as compared to the chitosan parent, while the microbiological screening demonstrated their self-defense properties against common and virulent pathogen agents. It was concluded that the reversibility of imine forming promotes the self-assembling of imino-chitosan biopolymer films into a lamellar morphology and, on the other hand, the slow release of the antimicrobial aldehyde in the microbiological culture. The obtained results demonstrate that chitosan polyamine is a challenging workbench to functional biodynamic materials.

Immunoglobulin G immobilization on PVDF surface.

Immobilization of antibody molecules onto hydrophobic polymeric surfaces with disordered orientation is something unwanted in many applications. To overcome this drawback, controlled immunoglobulin G (IgG) immobilization onto poly(vinylidene fluoride) surface was investigated in this paper. A two-step process involving radiofrequency plasma pretreatment for polymer surface functionalization, followed by coupling reaction was developed, after which immunoglobulin G was immobilized onto the surface directly or via protein-A. IR and XPS data proved that the process is more efficient when the radiofrequency plasma pretreatment was performed using N2 and N2/H2 as discharge gases. NIR-CI, AFM and XPS surface evaluation revealed that immobilization of IgG onto N2/H2 plasma-treated PVDF via grafted protein-A was achieved with an ends-on orientation, leaving available the antigen binding sites of IgG. This procedure could be a promising route for the preparation of oriented IgG assembly onto PVDF, useful in biomedical, membranes or sensors applications. QCM results showed a better antibody-antigen interaction when IgG immobilization onto PVDF substrate is mediated by protein A.