Preparation And Properties Of Thiol-Ene Photopolymerization Hydrogel

"Thiol-ene" photopolymerization of hydrogel refers to the molecules containing double bonds and thiol groups in the ultraviolet or visible light irradiation by intramolecular or intermolecular cross-linking reaction to generate three-dimensional network structure of the hydrogel.Compared with bio-medical hydrogel prepared by traditional methods."Thiol-ene" photopolymerization of hydrogels have the following typical advantages:(1)Which can polymerization fast under the human body temperature and control the structure(3)The polymerization process produces lower heat.which avoid burn tissue(4)Which can improve the strength of hydrogel by forming a dual network structure(5)Which can avoid the oxygen blocking effect in the polymerization process(6)The volume shrinkage is small when polymerization process.These characteristics of the thiol-ene photopolymerization biomedical hydrogel can overcome the problem.Which is traditional medical hydrogel being slow and poor control of structure,weak mechanical strength and poor biocompatibility.So the thiol-ene photopolymerization biomedical hydrogel is expected to be widely used in tissue engineering.In this paper,methylacrylated polyvinyl alcohol,maleated chitosan and maleated hyaluronic acid.That with photoactive groups was designed and synthesized.The methacrylated polyethylene(MPVA)/Thiolated polyvinyl alcohol(HSPVASH)system,Maleated chitosan(MCS)/Thiolated polyvinyl alcohol(HSPVASH)system,Maleic hyaluronic acid(MHA)/ Thiolated polyethylene glycol(HSPEGSH)system.Which three systems belong to "thiol-ene" photopolymerization of hydrogel.The gel kinetics,microstructure,compatibility and mechanical properties and so on of the hydrogels were studied by means of optical rheometer,scanning electron microscope,X-ray diffractometer and universal material testing machine.The swelling kinetics,degradation in vitro were studied by weight method and enzymolysis.In addition,the cytocompatibility of the hydrogels was studied by cytotoxicity and cell culture assays.The main results show that:(1)HSPVASH / PVAGMA system.Which was non-biodegradable hydrogel system.The starting gel point was 17 s of this hydrogel.The compressive strength was as high as 8.0 MPa.Which volume change rate and mass rate of change were less than0.1% under simulated human body environment 7 days.The hydrogel were non-toxic to L-929 cells.(2)HSPVASH/MCS system.Which was partially degradable system.The initial gel point of the hydrogel was 106 s.which was much lower than single gel system of the MCS.The compressive strength was 0.275 MPa.The hydrogel was non-toxic to L929 cells,and benifit to cells adhere,grow and proliferate on their surface.(3)HSPEGSH /MHA system.Which was a fully biodegradable hydrogel system.The initial gel point of the hydrogel was 20 s.The compressive strength could reach1.4 MPa.The degradation rate was 90%.The hydrogel was non-toxic to L929 cells.The above "thiol-ene" photopolymerization hydrogel system has many advantages such as gel fast,structure controllable,high mechanical strength and good cell compatibility.So which is expected to be widely used in tissue engineering.