Enzymatic hydrolysis of native collagen and fibrinogen was carried out under comparable conditions at room temperature. The molecular weight parameters of proteins before and after hydrolysis by thrombin were monitored by gel-penetrating chromatography (GPC). An analysis of the experiment results shows that the molecular weight parameters of the initial fibrinogen (Fn) and cod collagen (CC) are very similar. High molecular CC decays within the first minute, forming two low molecular fractions. The main part (~80%) falls on the fraction with a value of M_w less than 10 kDa. The initial high molecular fraction of Fn with M_w ~320–340 kDa is not completely hydrolyzed even after three days of control. The presence of low molecular fractions with M_w ~17 and M_w ~10 kDa in the solution slightly increases within an hour and noticeably increases for three days. The destruction of macromolecules of high molecular collagen to hydrolysis products appears almost completely within the first minute mainly to the polymer with M_w ~10 kDa, and enzymatic hydrolysis of fibrinogen proceeds slower than that of collagen, but also mainly to the polymer with M_w ~10 kDa. Comparative photos of the surfaces of native collagen, fibrinogen and the scaffold based on them were obtained.

Graft copolymerization of methyl methacrylate onto cod collagen was carried out under visible light irradiation (λ = 400–700 nm) at 20–25 °C using the RbTe_1.5W_0.5O₆, CsTeMoO₆, and RbNbTeO₆ complex oxides with β-pyrochlore structure as photocatalysts. The as-prepared materials were characterized by X-ray diffraction, scanning electron microscopy, and UV-Vis diffuse reflectance spectroscopy. It was also found that RbNbTeO₆ with β-pyrochlore structure was not able to photocatalyze the reaction. Enzymatic hydrolysis of the obtained graft copolymers proceeds with the formation of peptides with a molecular weight (MW) of about 20 and 10 kDa. In contrast to collagen, which decomposes predominantly to peptides with MW of about 10 kDa, the ratio of fractions with MW of about 10 kDa and 20 kDa differs much less, their changes are symbatic, and the content of polymers with MW of more than 20 kDa is about 70% after 1 h in the case of graft copolymers. The data obtained indicate that synthetic fragments grafted to the collagen macromolecule do not prevent the hydrolysis of the peptide bonds but change the rate of polymer degradation. This is important for creating network matrix scaffolds based on graft copolymers by cross-linking peptides, which are products of enzymatic hydrolysis.

This article presents new composite materials with cross-linked structures based on grafted copolymers of collagen with acrylates, which were prepared under photocatalytic conditions using the complex oxide RbTe_1.5W_0.5O₆ and additional modifiers. Cross-linking agents for acrylate fragments were used. Triethylene glycol dimethacrylate (TEDMA) was used in small volumes, and acrylic acid (AA) was used in an amount similar to the MMA concentration. The properties of the obtained graft copolymers were studied. Thus, collagen containing acrylate graft copolymers with cross-linked structures, which are highly soluble in water, was obtained. Addition of the protein substrate modifier (polyethylene glycol (PEG)) in an amount comparable to collagen resulted in a coagulate with a cross-linked structure. The gel easily released water during drying in vacuum and formed a polymer composite film. According to the results, the new polymer materials which were obtained were fungi-resistant. Due to observed properties, the obtained polymer samples could be considered as new materials for medical products, including colloidal solutions, gels, films.

In order to obtain a graft copolymer of polybutyl acrylate (PBA) on the substratum of emulsified fish collagen, RbTe1.5W0.5O6 complex oxide was used as a photocatalyst under visible light irradiation (λ = 400–700 nm). The emulsion was prepared by mixing the monomer and the aqueous collagen solution in a ratio of 1:2. Next, the catalyst was introduced into the resulting mixture, followed by stirring and ultrasound treatment. Before the reaction, the emulsion was bubbled with argon for 15 min. The reaction was carried out in an argon flow with continuous stirring. The radiation source was a 30 W visible light LED lamp placed at a distance of no more than 10 cm from the reaction mixture. At the end of the reaction, the emulsified organic phase was extracted with toluene, followed by phase isolation. In order to isolate the catalyst, the aqueous part of the solution was centrifuged for 30 min. Subsequently, the powder was repeatedly washed in distilled water at a temperature of 50 °C. The washed catalyst was dried, and the surface of the oxide after emulsion polymerization was examined using a scanning electron microscope. For the PBA–collagen graft copolymer emulsion isolated from the aqueous phase, molecular weight characteristics confirming the formation of a graft copolymer were obtained. It was established that the nitrogen content of amino acid residues in the PBA–collagen graft copolymer is significantly lower than in collagen, which indicates the formation of a graft copolymer. An analysis of films and sponges of PBA–collagen graft copolymer samples by scanning electron microscopy (SEM) showed a new structural-relief organization compared to collagen. A SEM analysis of the RbTe1.5W0.5O6 powder surface after the synthesis of the PBA–collagen graft copolymer detected fragments of polymer macromolecules on its surface. This can be explained by the fact that the catalyst used not only is a source of hydroxyl radicals, but сan also participate in the formation of a polymer on the powder surface due to the abstraction of a hydrogen atom from hydroxyl groups on its surface under the action of a hydroxyl radical.

Влияние способа выведения компонента инициатора из комплекса триэтилбор – гексаметилендиамин на молекулярно-массовые характеристики сополимеров бутилакрилат – винилбутиловый эфир при компенсационной сополимеризации в кипящем мономере