STUDY OF STRUCTURAL, PHYSICAL AND MECHANICAL FEATURES OF COMPOSITE MATRICES BASED ON SILK FIBROIN AND POLYURETHANE

Highlights The study included the analysis of structural, physical and mechanical properties of composite matrices based on silk fibroin (SF) and polyurethane (PU) with different component ratios. Abstract Background. SF is a polymer of natural origin, suitable for tissue engineering. Combining it with elastic polymers can improve the physical and mechanical properties of the material, making it a promising material for vascular patches in cardiovascular surgery. Aim. To study the structural, physical and mechanical features, as well as to evaluate the hydrophilicity and adsorption of proteins by the surface of composite matrices based on SF and PU with different ratios of components. Methods. Matrices were manufactured by electrospinning at a ratio of SF and PU of 3:1, 2:1, 1:1, 1:2, 1:3. Matrices of 10% SF and 10% PU served as controls. The ultrastructure of the composites (fiber thickness, pore size, and material porosity) was studied using SEM-images. The following physical and mechanical parameters of the matrices were measured: tensile strength, relative elongation, and Young's modulus. The hydrophilic properties of the matrix surface were estimated by measuring the contact wetting angle. The adsorption of albumin and fibrinogen by the matrix surface was studied. Results. All scaffolds produced by electrospinning had a porous-fibrous structure. Increasing the PU content resulted in the presence of adhesions and isolated cracks of fibers on the inner surface of the scaffolds after steam crosslinking of the polymers. The combination of SF and PU increased the strength and elasticity of the scaffolds compared to pure SF and brought them closer to native human a. mammaria in their ability to resist stretching. Adding PU to the SF composite reduced its initial hydrophilicity compared to pure 10% SF. Albumin adsorption was the same for all scaffolds; fibrinogen was adsorbed to a greater extent on scaffolds with a predominance of SF in the composition. Conclusion. Addition of PU to the composition of the SF composite does not disrupt the porous-fibrous structure of the matrix, increases its strength and elasticity, brings its properties closer to those of the native human artery, and also reduces the adsorption of fibrinogen, which expands the possibilities of this material for use in cardiovascular surgery as vascular patches.