| Cell migration is an important biological activity. Regulation of cell migration is critical in tissue regeneration such as angiogenesis, wound healing and bone formation. Among them, the migration of vascular smooth muscle cells (VSMCs) is an important process in therapy of cardiovascular diseases.In this thesis, methoxy poly(ethylene glycol)(mPEG) brushes of different molecular weight (Mw2kDa,5kDa and10kDa) and grafting mass (0-859ng/cm2) were prepared on aldehyde-activated glass slides, and were characterized by X-ray photoelectron spectrometer (XPS) and quartz crystal microbalance with dissipation (QCM-D). Adhesion and migration processes of VSMCs were studied as a function of different mPEG Mw and grafting density. These events were mainly regulated by the grafting mass of mPEG regardless of mPEG Mw and grafting density. The VSMCs migrated on the surfaces randomly without a preferential direction. Their migration rates increased initially and then decreased along with the increase of mPEG grafting mass. The fastest rates (～24μm/h) appeared on the mPEG brushes with grafting mass of300-500ng/cm2depending on the Mw. Cell adhesion strength, arrangement of cytoskeleton, and gene and protein expression levels of adhesion related proteins were studied to unveil the intrinsic mechanism. It was found that the cell-substrate interaction controlled the cell mobility, and the highest migration rate was achieved on the surfaces with appropriate adhesion force.PEG gradient were then fabricated using an injection method and served as a model surface for studying the cell migration behavior in vitro. By constructing patterns on the PEG gradient surface, periodic20μm wide stripes with antifouling and gradient profile were further generated. The VSMCs exhibited better adhesion and spreading on regions with a lower density of PEG and preferential movement toward this region. Although few work has been reported on chemotactic movement of cells on PEG gradients, this phenomenon is attributed to the imbalance of adhesiveness guiding cells transfer to more adhesive region. The directionality and chemotactic index of cell migration was further improved, resulting in values as high as0.7and0.53, respectively. Besides, up to69%cells migrated in the gradient direction. These results confirm that the migration of VSMCs is effectively directed on the patterned PEG gradient surfaces.Basic fibroblast growth factor (bFGF) is a powerful chemoattractant and mitogen. bFGF was conjugated on heparinized-glass slides. Its density was varied between0-295ng/cm2as characterized by XPS and QCM-D. Activity of the conjugated bFGF was confirmed with immunofluorescent staining. The mobility of vascular smooth muscle cells (VSMCs) was largely dominated by the bFGF density, whereas that of mesenchymal stem cells (MSCs) and endothelial cells (ECs) was not influenced. The migration rate of VSMCs increased initially and then decreased along with the increase of bFGF density. The fastest rate (～22μm/h) was found on the bFGF surface with a density of83ng/cm2. Cell number, spreading area, focal adhesion formation, adhesive strength and expression levels of migration-related proteins were studied, revealing that the cell mobility was regulated by intracellular signals especially myosin IIA.The bFGF gradients were finally fabricated using an injection method. The density of bFGF gradually increased from about130ng/cm2to300ng/cm2with a slope of17ng/cm2/mm. At different positions of bFGF gradient, the VSMCs adhesion number and cytoskeleton morphology kept similar. Due to the strong chemoattractive ability of bFGF, about60%cells orientated themselves along the gradient with an angle<30°. In addition, bFGF gradient could effectively induce the directed migration of VSMCs. Up to60%cells tended to migrate towards the region with a higher density of bFGF. The values of directionality and chemotaxis index significantly increased, indicating that a type of gradient materials is successfully prepared, which can effectively induce the directional migration of VSMCs.
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