Synthesis And Characterization Of UV Crosslinked Chitosan/Hyaluronic Acid Hydrogel

Skin wound healing has always been a difficult problem in the medical field.Hydrogel skin wound dressing is a kind of wound dressing with good application prospect.In this paper,chitosan（CS）and hyaluronic acid（HA）are two kinds of natural biomaterials used to prepare hydrogels.By modifying CS and HA,three series of hydrogels are prepared.The physicochemical properties of the prepared hydrogels are investigated.Methacrylic anhydride（MA）was used to modify CS to prepare two kinds of methylacrylated chitosan（CSMA）hydrogels,and then UV crosslinking CSMA was used to form the light-induced crosslinking methylacrylated chitosan（LCSMA）hydrogels.The chemical structure of CSMA was characterized by Hydrogen nuclear magnetic spectra and Fourier-infrared spectroscopy.Water solubility and Zeta potential of CSMA were also determined.The microstructure of LCSMA hydrogel was observed by scanning electron microscope（SEM）.The structure of LCSMA hydrogel was porous and loose.The thermodynamic properties of CSMA and LCSMA hydrogels were determined by differential scanning calorimetry（DSC）.LCSMA hydrogels have good thermal stability.The relationship between CSMA double bond substitution degree and mechanical properties,swelling properties and degradation properties of hydrogels was also studied.The hydrogel with high double bond substitution degree had better mechanical properties,higher water contact angle,lower swelling rate and slower degradation rate.On the basis of LCSMA hydrogel,the biocompatibility,mechanical strength and water absorption of hydrogel were improved.Methylacrylated hyaluronic acid（HAMA）was synthesized.Then HAMA and CSMA were mixed and irradiated with ultraviolet light to form the photocrosslinked CSMA/HAMA（CM/HM）hydrogel.The thermodynamic properties of HAMA and CM/HM hydrogels were determined by DSC.The CM/HM hydrogels showed good thermal stability after the photocrosslinking of HAMA and CSMA.The relationship between the degree of double bond substitution of HAMA and CSMA and the mechanical properties,water contact angle,swelling property and degradation property of CM/HM series hydrogels was also studied.The hydrogel with high double bond substitution degree CSMA-2has better mechanical properties and higher water contact angle.The hydrogels with high double bond substitution degree HAMA-2 have lower equilibrium swelling rate and slower degradation rate.On the basis of CM/HM hydrogel,in order to improve the tissue adhesion and antibacterial activity of CM/HM hydrogel,catecholylated chitosan（CSDA）was introduced into CM/HM polymer system.CSMA/HAMA/CSDA（CM/HM/CSD）hydrogel with interpenetrating network was synthesized by mixing CSDA,HAMA and CSMA with UV crosslinking and oxidizing crosslinking of Na IO₄.The properties of CM/HM/CSD hydrogels were studied.The CM/HM/CSD hydrogels with interpenetrating network had better mechanical properties,higher water contact angle,lower swelling rate and slower degradation rate than the hydrogels with only optical cross-linking network.