Structure and properties of fibrin/polyvinyl alcohol interpenetrating polymer network hydrogel as a modifying coating for small-diameter vascular grafts

Background: Interpenetrating polymer network (IPN) hybrid hydrogels enable regulating their properties by varying the composition and concentration of their components. Fibrin is an available natural polymer with ideal biological properties but low strength and tendency to retraction. Polyvinyl alcohol hydrogels are stable, comparable in strength to biological tissues but bioinert. Fibrin/polyvinyl alcohol (F/PVA) IPN can overcome the shortcomings of each component and create an improved material for tissue engineering. Objective: To assess the possibility of and conditions for obtaining a homogeneous IPN by subsequent fibrin polymerization and polyvinyl alcohol cryostructuring while preserving as much as possible mechanical and biological properties beneficial for tissue engineering. Methods: F/PVA IPN was obtained by subsequent fibrin polymerization (30 mg/mL) and polyvinyl alcohol cryostructuring (15, 30, and 60 mg/mL). We studied the structure using a scanning electron microscope, histology, infrared spectroscopy, and X-ray diffraction analysis. We tested mechanical properties and shrinkage of the samples. Biological features were assessed in vitro in terms of viability, cell count, proliferative and metabolic activity of EA.hy926 endothelial cell culture. Results: Our study found the maximum amount of fibrin on the surface of F30PVA15 IPN and its minimum amount on the surface of F30PVA60. These results were supported by the high biological appeal of F30PVA15 compared with F30PVA30 and F30PVA60. F30PVA60 hydrogels demonstrated shrinkage resistance compared to the template; F30PVA30 and F30PVA15 samples decreased by 1.4 and 2.5 times, respectively. Although the mechanical strength of all monocomponent hydrogels and IPN samples did not compare to that of the internal thoracic vein, F30PVA30 and F30PVA60 demonstrated better results than F30PVA15 and fibrin alone. Conclusion: Our method allows obtaining shrink-resistant IPN hydrogels with improved mechanical and tolerable biological properties at polyvinyl alcohol concentrations of > 15 mg/mL and function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }