Effect Of Microstructure Of Vascular Tissue Engineering Scaffolds On Cell Migration

With the improvement of people's living quality and the accumulation of bad living habits,cardiovascular disease has gradually become one of the main causes which threatens human health.In order to make this stubborn disease completely eradicated,vascular tissue engineering provides a new way for the removal of diseased organs and vascular tissue reconstruction.An ideal scaffold for vascular tissue engineering should share similar surface topography characteristics,structure,mechanical properties and good biocompatibility with the natural extracellular matrix(ECM).Abundant collagen fibers in ECM provide a suitable mechanical environment and structural support for cells.The "D-banding pattern" structure composed of collagen molecules arranged in spirals on its surface is essential to connect cells and ECM.In this paper,poly(?-caprolactone)(PCL)was applied to fabricate samples with different topologies;the mechanical properties,biocompatibility and cell migration on samples were investigated.The works are listed as below:In Chapter 2,three groups of samples with different surface topologies were obtained by hot pressing,electrospinning fibers received by a plate and a roller collector.Great difference in the topological morphology of the samples was detected: the surface of R-PCL was smooth;the fibers of R-PCL were random deposited while the fibers of A-PCL were aligned.The FFT analysis showed a great difference between R-PCL and A-PCL in the value of peak FFT,which meant the alignment of fibers quantitatively.Cells cultured on A-PCL showed a promoted proliferation and an elongated cell shape.In Chapter 3,the SINSK structure was fabricated on the aligned fibers by selfinduced crystallization and the kebab size was controlled by the PCL concentration.As the PCL concentration increased,kebab size became larger,the hydrophilicity and roughness were promoted.As for the mechanical properties,opposite trends were discovered before and after a strain value of approximately 10%.The ductility and stiffness were improved because of the “tie” sites resulted from SINSK structure.In Chapter 4,the endothelial cells were seeded on the samples mentioned in Chapter 3 to investigate the biocompatibility and cell migration.The results showed that as the kebab size increased,the cell proliferation,adhesion and migration speed were promoted;the migration trajectories were equally distributed directionally consistent with the fiber's alignment;the nuclear shape index increased and cells were less elongated,while the adhesion was more polarized.The results provide a new way to contribute the rapid endothelialization in tissue engineering.