The aim of investigation was to develop a system for protein sustained release based on the use of poly(3-hydroxybutyrate) (PHB) microcapsules loaded with bovine serum albumin (BSA).Materials and Methods. To develop microcapsule we used PHB obtained microbiologically by a strain-producer Azotobacter chroococcum 7B. Microcapsules loaded with model protein BSA were produced by double emulsion technique "water/oil/water". Morphology of microcapsules was investigated by methods of confocal and scanning electron microscopy, when the loading and release of BSA was examined spectrophotometrically. In vivo biocompatibility of microcapsules was studied in accordance with intramuscular implantation and histology findings.Results. The study of BSA incorporation and its sustained release from microcapsules for more than 190 h demonstrated the efficacy of proposed system. The mechanism of protein release was found to occur due to the rupture of polymer walls. Moderate tissue response to the implantation of obtained microcapsules was demonstrated.Conclusion. Developed PHB microcapsules loaded with BSA are good model of long acting protein drugs.

Investigations of membrane active peptides can be considerably enhanced using advanced approaches based on the confocal laser scanning microscopy (CLSM). Studies of the latarcin Ltc1 interactions with erythrocytes exemplify this statement. Conventional and time-lapse CLSM analysis reveals the features of Ltc1 binding to erythrocyte membrane, transformations of erythrocytes on the way from discocytes to ghosts, stages and dynamics of the membrane pore formation as well as the pore size and its dependence on the Ltc1 concentration. The obtained results demonstrate that CLSM is a powerful tool to study functional features of membrane active peptides and clarify mechanisms of peptide-cell interactions.

The antimicrobial peptide Ltc1-K and its derivates without one, two, then three N-terminal amino acid residues were studied based on the hypothesis (backed by some experimental data) that the hydrophobic N-terminal moiety of linear cationic antimicrobial peptides defines their haemolytic activity. It was discovered that the excision of three N-terminal amino acid residues considerably decreases the peptide’s toxicity for eukaryotic cells and simultaneously increases the selectivity of antibacterial activity for some bacteria species. Studies performed with the model membrane systems and human erythrocytes revealed that the main reason for the observed effect is a multifold decrease in the peptide’s affinity to an eukaryotic cellular membrane enriched with zwitterionic phospholipids.