Scaffolds For Tissue Engineering Topology And Chemical Composition Of Cell Behavior

Tissue engineering scaffolds is one of the most important issues of tissueengineering. In the recent years nanofibrous scaffolds with 3D structure have attractedintensive interests because of providing the micro-environment mimicking the natureextracellular matrix. Various materials have been tried to fabricate nanofibrousscaffolds for tissue regeneration and repair.Carbon nanotube (CNT) is a new member of carbon family with nano-scale.Researchers have pay increasing attention to carbon nanotubes because the newcarbon material has wonderful mechanical properties and conductive ability, whichallow it to be perfect enhancement element for composites preparation, as well as toimprove the hemocompatibility of polymeric matrice greatly for its pure carboncomposition.In this study, two kinds of biomimetic nanofibrous scaffolds and PU casting filmswith micro- and nano-pattern were fabricated to evaluate the fibroblast cells growthbehaviors. One of the nanofibrous scaffolds is nonwoven single walled carbonnanotubes (nonwoven SWNT) with nanotopographic structure and macroscopicvolume fabricated by the floating chemical vapor deposition method; the second oneis electrospun films of carbon nanotubes/polyurethane composite (MWNT/PU),which called nonwoven MWNT/PU in this dissertation.The morphology of nonwoven SWNT and nonwoven MWNT/PU were observedand characterized through scanning electron microscopy (SEM) and surface chemistryof nonwoven SWNT were analyzed by X-ray photoelectron spectroscopy (XPS). Thecells growth behaviors including adhesion, proliferation, cytoskeletal developmentwas investigated by using cell viability assay and confocal observation respectively.The proteins secreted by the cells growing on nonwoven MWNT/PU were analyzedby SDS polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometryrespectively.The experimental results indicated that the scaffolds with nanotopography andcarbon nanotubes exhibited significant enhancement to the cells adhesion andlong-term proliferation. Numerous and well organized cytoskeletal structures were observed when the cells were cultured in nonwoven SWNT, and long synapse and cellsheets were observed when the cells were cultured on the scaffold after 6h and 2d,implying that the scaffolds encourage cell-cell communication and cell migrationFurthermore, biosynthesis and secretion of collagen of the cells growing on nonwovenMWNT/PU were boosted, which is benefit to extracellular matrix reconstruction.The results obtained in this work are of significance to in vitro cell amplificationin large scale, tissue regeneration or guided repair, as well as biomedical deviceapplication.