Formation of Hydroxyapatite-Based Hybrid Materials in the Presence of Platelet-Poor Plasma Additive.

Biomaterials based on hydroxyapatite with controllable composition and properties are promising in the field of regenerative bone replacement. One approach to regulate the phase composition of the materials is the introduction of biopolymer-based additives into the synthesis process. The purpose of present study was to investigate the formation of hydroxyapatite-based hybrid materials in the presence of 6-24% platelet-poor plasma (PPP) additive, at a [Ca]/[PO] ratio of 1.

[Biodegradablescaffolds based on chitosan: Preparation, properties, and use for the cultivation of animal cells].

The influence of the conditions of the formation of chitosan hydrogels crosslinked with glutaraldehyde (GA) or genipin (the polysaccharide molecular weight, pH level, and concentration of the chitosan solution) on the gel time and the properties of biopolymer scaffolds for tissue engineering obtained by the freeze-drying of hydrogels was studied. The resulting scaffolds had different structures (morphology, degree of anisotropy, average pore size) and moisture-retaining capacities. The cytotoxicity of biodegradable scaffolds based on chitosan with a low content of genipin and GA was studied for the first time.

[Mechanism of the reaction of glutaraldehyde with chitosan].

The regularities of the reaction of aminopolysaccharide chitosan with glutaraldehyde (GA) have been considered. The equilibrium forms of GA in water have been thoroughly studied by NMR spectroscopy. It has been established that at pH 5.

[Antimicrobial activity of core-sheath surgical sutures modified with poly-3-hydroxybutyrate].

To impart antimicrobial activity to surgical sutures, weaved polyester fibers are coated with poly-3-hydroxybutyrate (PHB), containing the antimicrobial agent furazolidone (FZ). The prolonged FZ effect (7-14 days) is achieved by two-step application of a sheath, constituting 10% of the suture weight and containing 2-6% FZ. The sheath structure and antimicrobial activity of sutures can be modified by the introduction of other biocompatible and biodegradable polymers.

[Preparation of biodegradable porous films for use as wound coverings].

We studied the preparation of polymeric films formed from solutions of poly-3-hydroxybutyrate and poly-epsilon-caprolactone in chloroform and methylene chloride. A morphological study of film chips (electron microscopy) showed that solvent evaporation results in the formation of a heterogeneous structure with interpenetrating pores (1-20 microm). We proposed a new method for introducing the proteolytic enzyme and the aminopolysaccharide chitosan into the composition of polyester films.

[Rational organization of the technological processes of hydrolyzing whey lactose in the presence of a heterogeneous fiber biocatalyzer].

We have studied lactose hydrolysis in whey in the presence of a fibrous biocatalyst containing immobilized beta-galactosidase in a continuous-flow column reactor, and in a reactor unit with substrate recycling in batch and continuous regimes. The comparative study of the efficiency of the reactors allowed us to recommend the reactor unit with substrate recycling for lactose hydrolysis in whey in the batch regime, since it provides both satisfactory hydrodynamic stability and high productivity.

[Effect of the structure of polymeric materials on the properties of immobilized enzymes].

The relationship between the structure of triacetate cellulose fibres and films and properties of enzymes entrapped in these materials was investigated. Trypsin and penicillin amidase were entrapped in triacetate cellulose films and fibres during their formation. The effect of permeability of the films on the catalytic properties of entrapped trypsin was studied.

[Preparation of films and fibers containing proteolytic enzymes].

Immobilization of the proteolytic enzymes trypsin and terrylitin in fluorplastic-42 films and fibers as well as in water-soluble polymeric (polyvinyl alcohol and carboxymethyl cellulose) films was being studied during preparation of the films. The properties of the proteolytic enzymes immobilized in the polymers are dependent on the conditions of preparation of fibers and films.

[Immobilization of modified alpha-chymotrypsin within the structure of cellulose triacetate membranes].

Immobilization of alpha-chymotrypsin on carboxymethyl esters of dextran (mol. weights of 60 000 and 100 000), whose macromolecules contain 2-amino-4-chloro-s-triazine residues, results in water-soluble polymeric derivatives of alpha-chymotrypsin, containing up to 60% of the enzyme. The activity of the immobilized enzyme makes up to 90% of the initial one.