Effect Of Biomechanical Microenvironment On Collage Molecule Self-Assembly In Vitro

Collagen molecule,one of the main structural protein of vertebrates,is selfassembled to form hierarchical structures,from single molecules tropocollagen to fibrils,fibers and finally constitutes organ and tissue with specific structural characteristics.It is clear that collagen self-assembly are influenced by biomechanical microenvironment,however,how the biomechanical force alters structures of collagen molecules and how the structural alteration affects the processes of selfassembly is not well understood.Therefore,it is of great significance to study the effect of biomechanical microenvironment on collage molecule self-assembly in vitro,which will shed light on tissue regeneration and tissue engineering repair.In this dissertation collagen molecules from both rat tail and bovine are adopted as model,while atomic force microscope is utilized as research tool for biomechanical characterization with nanoscale resolution.The specific research content is as follows,(1)investigate the effect of collagen sources on self-assembly pattern: it was found that collagen from various sources significantly affects the self-assembly pattern even grown on the same substrate,and fascicular pattern showing by bovine collagen molecules while cross-linked network by rat tail;(2)study the impact of substrate on collagen self-assembled fibril: self-assembly of collagen molecules is surfacemediated,showing triangular pattern orientation arrangement on muscovite mica and parallel pattern to each other on phlogopite mica;(3)inquire into the collagen dynamic growth process on muscovite mica substrate: it is concluded radial first and then axial growth when collagen molecules self-assembled into fibril,however,due to the fiber-fiber interaction,the self-assembled structure becomes tighter and diameter of collagen fibril shrinks a little bit after long time of culture;(4)work on the interaction of collagen molecules with hyaluronic acid: it is summarized that hyaluronic acid improves the capability of collagen to absorb additional water molecule and increases the diameter of fibril.The results of this dissertation will provide theoretical and practical reference for collage-based nanomaterials in tissue engineering.