Fabricationof Multifunctional High Strength Hydrogelsfor Biomedical Applications

In this thesis,ion-responsive hydrogen bonding strengthened hydrogels?termed asPVV?weresynthesizedbyone-potcopolymerizationof2-vinyl-4,6-diamino-1,3,5-triazine?VDT?,1-vinylimidazole?VI?and polyethylene glycol diacrylate.The diaminotriazine-diaminotriazine?DAT-DAT?H-bonding interaction contributed to a notable increase in comprehensive performances.In addition,introducing m M levelof zinc ions could further increase the mechanical properties of PVV hydrogels and thus fix a variety of temporary shapes due to the strong coordination of zinc with imidazole.Remarkably,a multi-walled hydrogel tube?MWHT?fixed with Zn²⁺demonstrated much higher flexural and compressionstrengths than the solid hydrogel cylinder?SHC?.Because of the release of zinc ions,the hydrogel exhibited an effective antibacterial effect in vitro.A Zn²⁺-fixed MWHT was implanted subcutaneously in rats,and it was found that the Zn²⁺-fixed MWHT demonstrated anti-inflammatory and wound healing efficacies.Based on the PVV hydrogelsynthesized above,we also constructed high strength conductivehydrogel?termed as PVV-PANI?by post-coatingwith polyaniline?PANI?.The PVV-PANI hydrogels supported the attachment,proliferation,and differentiationof nerve stem cells?NSCs?,and elictedthe efficientdifferentiation towardneuronand glia via electrical stimulation.In this work,a mineralized high strength and tough hydrogel was synthesized by copolymerization of acrylonitrile,1-vinylimidazole and polyethylene glycol diacrylate,followed by in situ precipitationmineralization.The dipole-dipole pairings combined with the interaction of hydroxyapatite?HAp?nanoparticleswith polymer chains contributed to a tremendous increase of tensile/compressive strength,modulus and fracture energy.The maximum tensile,compressive strengths and fracture energy could reach 6.1 MPa,11.5 MPa,and 7935 kJ/m²,respectively.The mineralized hydrogel was shown to facilitate the attachment and proliferation of C2C12 cells.The mineralized hydrogel was implanted into an 8 mm-diameter critical-size of calvarial defect of rats to evaluate the bone regeneration.12-week postsurgical results revealed that the mineralized hydrogel exhibited the highest bone volume and density within the defect as measured by computed tomography and histology.This work offers a new strategy to fabricate high strength hydrogel.