Preparation And Properties Of 3D Printable Hyaluronic Acid Double Network Hydroge

The hydrogel is a kind of soft and wet polymer material composed of hydrophilic three-dimensional polymer network and a large amount of water.Hydrogels are widely used in many fields due to their good swelling property,biocompatibility,reversible large deformation and intelligent response to various chemical or physical stimuli.The mechanical properties of traditional single-network hydrogels are weak.In order to improve the mechanical strength,a physical-chemical cross-linked double-network hydrogel based on hyaluronic acid was designed.The synthetic hydrogel is safe and non-toxic,has good mechanical properties,and has the characteristics of water-holding,biocompatibility,bacterial barrier,and slow-release capacity of drugs.It can be used as3D printing material and applied in wound dressings and drug carriers.The specific research contents are as follows:（1）Hyaluronic acid double-network hydrogels were synthesized by physical-chemical crosslinking.The structure of hydrogels were characterized by SEM,FT-IR,XRD and XPS.The results show that acrylamide（AM）is completely polymerized into PAM.And there is a coordination effect of the metal ligands in the hydrogel.The hydrogel has uniform and compact pore structure with pore diameter of 10～20μm.In addition,the hydrogel is amorphous.（2）The properties of hydrogels were studied by thermogravimetric analysis,tensile property test and rheological property test.The results show that hydrogels have good thermal stability,mechanical properties and shear thinning properties.Moreover,these properties are affected by Zn²⁺.The dissipation mechanism of the hydrogel is mainly realized through the synergistic action of dynamic physical cross-linking network and PAM network to bear large stress and deformation.（3）The swelling capacity and environmental sensitivity of hydrogels were studied by measuring swelling performance of water content and p H sensitivity.The results show that hydrogels have good hydrophilicity and can absorb more than 10 times of their own weight of water and keep the water in the range of 30～50 h.The water content and water retention rate are negatively correlated with Zn²⁺.Hydrogels have a good swelling capacity,and the swelling process is controlled by both diffusion and relaxation.In addition,the hydrogel has a certain p H sensitivity,in an alkaline environment,swelling is hindered.（4）Acetylsalicylic acid（ASA）was used as a model drug to evaluate the potential of hydrogels as drug carriers.Finally,the antibacterial performance of hydrogels containing plant essential oil were tested.The results show that hydrogels have certain slow-release ability for ASA,and the drug release time is controlled at about 120h.The drug release behavior is pseudo-Fickian diffusion.Hydrogels can improve the inhibitory effect of plant essential oil on E.coli by embedding plant essential oil.Meanwhile,due to the presence of Zn²⁺,the hydrogel itself also has certain antibacterial activity.