| The use of the physical and mechanical properties of materials to regulate the biological functions of cells and tissues is a leading issue in the field of biomedical materials.Self-healing materials,as a new type of functional materials,can adapt to the dynamic environment changes in the body,self-heal the damage and possess dynamic controllability.It has broad applied prospects in three-dimensional cell culture,tissue engineering,drug delivery,etc.However,the regulation of the dynamic micro-nano structure on the surface of the self-healing material and its effect on cell adhesion and proliferation need to be further established and clarified.Based on above,an intrinsic self-healing material-methyl methacrylate-n-butyl acrylate copolymer[p(MMA/nBA)]is synthesized in present thesis,and the surface construction and microstructure and regulation to cell behavior of this self-healing material are explored,expanding the application of such self-healing materials and providing theoretical guidance for dynamic cell regulation and tissue regeneration.The main research work is as follows:(1)A series of self-healing and non self-healing p(MMA/nBA)copolymers were synthesized by radical polymerization technology,followed which the structure and properties of polymers were analyzed by nuclear magnetic hydrogen spectroscopy(~1H NMR),gel permeation chromatography(GPC),and differential scanning Calorimetry(DSC)and other methods.The self-healing property of p(MMA/nBA)copolymer membrane was investigated by mechanical tensile test.When the MMA/NBA molar ratio is 48/52 and 63/37 respectively,the tensile strain of the p(MMA/nBA)copolymer membrane recovered to 90%and 5%respectively,which is due to the bond lock interaction of adjacent chains.The existence of directional van der Waals force due to dipole interaction during chain separation will enhance the cohesive energy of chain entanglement or side-by-side chains,which is conducive to the self-healing of materials.Then,electrospinning method was used to construct p(MMA/nBA)micro/nano fiber structure,and its self-healing ability was consistent with that of p(MMA/nBA)membrane;cytotoxicity and proliferation experiments showed that the micro/nano fiber had good biocompatibility.(2)A PAAm molecular brush was grafted on the surface of p(MMA/nBA)membrane by UV initiated surface grafting technology,obtaining the p(MMA/nBA)-PAAm film surface with good hydrophilicity.The graft-modified membrane has good blood compatibility,which is manifested in anti-platelet adhesion,activation and low hemolysis rate.Based on this chemical grafting technology,the positive and negative patterns of PAAm molecular brush were successfully constructed on the surface of p(MMA/nBA)film by combining ultraviolet photolithography and photomask,realizing the controllable capture and adhesion of platelets and L929 mouse fibroblasts and the array capture of different cells.(3)The micro-pattern surface of p(MMA/nBA)film was constructed by physical imprinting using micron-copper mesh as the template and the morphology of the self-healing p(MMA/nBA)film before and after the recovery of the initial pattern was measured by the probe profilometer.It was found that the 9?m-deep groove in the self-healing p(MMA/nBA)film was almost flat after 12 hours.Meanwhile,dynamic micro-pattern can affect L929 cell proliferation and morphology,thus realizing the dynamic spatiotemporal regulation of cells.In summary,we explored the dynamic regulation of micro-nano structure of self-healing p(MMA/nBA)material on cells,which is expected to be used in the field of tissue regenerative medicine. |
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