Mechanical Reinforcement And Application Of Zwitterionic Hydrogels

As a biomaterial,hydrogels inevitably face the following problems in vivo:1)as a heterogenous material,the efficiency of hydrogels decreases with the immune response proceeding;2)application limitations due to lack of mechanical strength Aiming at immune response,Zwitterionic materials can reduce or even shield the immune recognition of organisms and increase biocompatibility of hydrogels due to their excellent non-specific protein adsorption.In view of the lack of mechanical strength,based on the dissipation of mechanical energy and the conduction of stress,the structures such as double network hydrogels and unfixed crosslinked hydrogels were designed and used in tissue engineering.However,at present,the prepared enhanced hydrogels still have limitations in practical applications.One of the problems is that it is impossible to cover the wide range of modulus required by biological tissues with a single hydrogel structureIn order to improve the mechanical properties of hydrogels while giving them a wide range of modulus,the monomers with intermolecular hydrogen bonding interaction and dipole-dipole interaction were selected to prepare hydrogels with synergistic effect under stress conditions by improving mechanical energy dissipation and stress dispersion.Subsequently,the biological properties of tissue engineering materials were evaluated,and the application of tissue engineering materials was explored.The main contents and conclusions are as follows1.The mechanical strength of hydrogels was enhanced by the synergistic effect between multilayer graphene oxide and hydrogen bonds of molecular chains under stress conditions,using the multilayer graphene oxide as the energy dissipation unit and the intermolecular hydrogen bonds to 2-hydroxyethyl methacrylate(HEMA)and acrylamide(AAm)as the copolymers.Repeated compression experiments confirmed the promotion of hydrogen bond formation by multilayer graphene oxide.A model of synergistic enhancement of hydrogel mechanical strength by flexible crosslinkers was established2.Based on the model of synergistic enhancement of hydrogel mechanical strength by flexible crosslinkers,methacrylated bovine serum albumin(mBSA)was used as energy dissipation unit,sulfobetaine methacrylate(SBMA)as zwitterionic monomer,and small molecule chemical crosslinker N,N-dimethyl bisacrylamide(BIS)as crosslinking agent to immobilize the hydrogel network.SBMA hydrogel with high compressive strength and structural integrity under ultra-high compressive deformation was prepared.The mechanical energy dissipation and elastic resilience of the hydrogel during compression were evaluated.It was confirmed that mBSA could be used as a flexible crosslinker to synergistically strengthen the hydrogel.3.Using mBSA as flexible crosslinker,the tryptase-degradable SBMA hydrogels were prepared by using mBSA with different modification degrees.The density of SBMA network was regulated by changing the concentration of modified protein,which affected the interaction between trypsin and protein crosslinker,thus controlling the degradation rate of hydrogel.The prepared hydrogels also showed excellent biocompatibility and non-cytotoxicity.4.In order to improve the tensile stress of SBMA hydrogels,a scaffold reinforced zwitterionic hydrogel(SRgel)was prepared by electrospun and BIS-crosslinked SBMA hydrogel as filler.SRgel has excellent anti-platelet and cell adhesion ability,which can effectively avoid the coagulation problems faced by small-caliber artificial blood vessel.In addition,electrospun further strengthens the dipole-dipole interaction between the SB units in hydrogel in the stretching process,and the more remarkable increase in modulus and strength can be achieved by stretching-induced SRgel.