Preparation And Properties Of Injectable Carboxymethyl Chitosan Supramolecular Hydrogels

Injectable supramolecular hydrogel can be injected directly into the designated site by simple in vitro injection,which can better fit irregular wounds,avoid secondary damage of traditional surgical implantation and provide an appropriate micro-environment for wound healing.At the same time,injectable supramolecular hydrogels with biocompatibility are widely used in tissue culture,cell proliferation,drug release and other biomedical fields.However,rapid and continuous preparation of injectable supramolecular hydrogels is still a difficult problem in gel preparation.Biocompatible carboxymethyl chitosan(CMC)was prepared via a substitution reaction by chloroacetic acid and chitosan in alkaline condition.A suitable carboxymethyl chitosan supramolecular hydrogel CMC-Zn was prepared by direct mixing with Zn(N03)2 at suitable pH value-The gelation process was characterized by FT-IR,NMR,UV-vis and XRD.The rheological properties of hydrogels were investigated by rotational rheometer.A two-channel injection system was designed and assembled based on microfluidic technology.CMC solution was used as core fluid,and Zn(N03)2 solution was used as sheath fluid for coaxial core-shell flow.Carboxymethyl chitosan supramolecular hydrogel was injectable in situ by diffusion of zinc ion into core fluid.The morphology of the gel fiber was characterized by optical microscope and SEM.It was found that the concentration of Zn2+,the inj ection velocity and the inner diameter of the collecting tube may influence the diameter of the gel fiber.Finally,the antibacterial properties of injectable carboxymethyl chitosan supramolecular hydrogels were characterized by the method of bacteriostasis circle.