Layered vascular grafts - mechanical properties and hemocompatibility

Jun 28, 2022, 2:10 PM
10m
Room: S4 A

Room: S4 A

Speaker

Łopianiak, Iwona (Doctoral School No 1, Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland)

Description

Cardiovascular diseases are the major cause of death worldwide. The lack of autologous vessels that can be used in cardiovascular surgeries compel engineers to look for nowel solutions. The main assumption of vascular tissue engineering is to design and produce functional materials that replace damaged blood vessels and restore their proper functions. Tissue-engineered vascular grafts with diameters >6mm are available on the market. However, the design and manufacture of prostheses with diameters ≤6mm is still a challenge for scientists due to their low hemocompatibility and thrombogenicity.

In this study two types of cylindrical layered structures with internal diameters ≤6mm were produced by the solution blow spinning method. The prostheses differed in the morphology of the internal surface. The first type of prostheses was characterized by a nanofiber inner surface, and the second was characterized by a solid one with small fibrous areas. The mechanical properties of the manufactured dentures were tested and compared. Then the surfaces of the prostheses were coated with polydopamine and biomolecules such as amino acids, short peptide sequences or polysaccharides were attached. The influence of the morphology of the internal surface and the presence of biomolecules on the hemocompatibility of the structures was investigated.

SEM analysis of grafts cross-sections has shown that manipulation of the solution blow spinning process parameters allows for the production of layered structures with differentiated morphologies of layers. Designed prostheses show high flexibility (Young’s modulus value of about 2.5MPa) and tensile strength (maximum load value of about 60N). Grafts produced of medical-grade polyurethanes do not cause hemolysis. Activation and adhesion of blood elements to the inner surface of the prosthesis depend on its morphology. Fewer platelets were observed on nano-fibrous surfaces than on microfibrous/compact surfaces. Modification of the surface of prostheses with biomolecules also reduced the number of attached platelets.

In conclusion, the solution blow spinning method allows the production of layered cylindrical structures with internal diameters ≤6mm and desired mechanical properties, while the surface morphology and attached biomolecules affect the number of attached and activated platelets.

This project was funded in part by National Science Centre, Poland, grant number: 2020/39/I/ST5/01131.

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