| An injectable thermo-sensitive double crosslinking hydrogel based on thiolatedchitosan （CS-TGA）/beta-glycerophosphate （β-GP） was prepared by combiningphysical and chemical crosslinking. The effect of the concentrations of CS-TGA andβ-GP on gelation temperature of CTG hydrogel was investigated. The gelation andmechanical properties of CTG in situ gel system were studied by oscillatory rheologyand unconfined compression testing. CTG system undergoes a fast gelation at bodytemperature within2minutes, and the gel is durable and its mechanical strength isstronger than CS-TGA hydrogel’s. The integrity of CTG hydrogel maintains for morethan30days both in vitro and in vivo, and the interior morphology by scanningelectron microscopy （SEM） reveals that the gel has interconnected porous networkstructure. In vitro release behavior of protein from CTG hydrogel was investigated.There is a sustained protein release from the gel without any initial burst. In vitrocytotoxicity, hemolysis and histopathological analysis reveal that the gel isbiocompatible.An injectable triple cross-linking network hydrogel （CTGP） is also prepared byphysical interaction, Michael addition and disulfide bond formation based on thiolatedchitosan （CS-TGA）, β-glycerophosphate （β-GP） and poly（ethylene glycol） diacrylate（PEGDA） without the addition of cytotoxic cross-linkers and catalysts. CTGPhydrogel containing a relatively low amount of β-GP (0.1mol·L-1) exhibits acontrollable gelation behavior under physiological conditions. Further, thecompressive modulus is improved differently by introducing PEGDA into the system.The presence of PEGDA in CTGP hydrogel imparts better swelling property, andthere is a sustained protein release from the hydrogel without any initial burst. In vitrocytotoxicity and hemolysis reveal that the gel is biocompatible. In vivo subdermalinjection into mice models further confirms the non-cytotoxicity of the hydrogel andthe hydrogel is highly resistant to degradation. |
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