Preparation And Characterization Of Injectable And Multiple-responsive Self-healing Hydrogels

Because of hydrogels,stable structure,high water content and biocompatibility,hydrogels are widely used in cell scaffolds,drug delivery,tissue engineering and so on.On the one hand,as a biomaterial,we hope that hydrogels can present the state of solution in vitro,and can be quickly gelated(injectable)when it was injected into the body;on the other hand,hydrogels can be degraded quickly after their work is completed in the body,so the hydrogels with stimulating response are particularly important.Therefore,this paper mainly introduces the use of biocompatible polymers to construct self-healing hydrogels with multiple responses.The main contents of the article are divided into two aspects as follows:(1)In this paper,an injectable hydrogel with pH and redox response was prepared.A single network hydrogel was formed by the reaction of Schiff base between oxidized sodium alginate(ADA)and double terminal hydrazide modified PEG(PEG-DTP).The hydrogel has the dual degradation and release properties of pH and redox,as well as injectable and self repairing properties.(2)A self repairing hydrogel network is formed by the reaction of PEO-PPO-PEO(F127-CHO)three block polymer with 3,3'-two thiohydrazide(propyl hydrazide)by modifying aldehyde groups at both ends.PEO-PPO-PEO is a thermosensitive polymer(LCST? 37?).The hydrogel system also has an imine bond and a disulfide bond.Multiple interactions give the hydrogel multiple responsiveness.What's more,PEO-PPO-PEO,as a kind of thermosensitive polymer,makes the hydrogel have a good injectable property,that is,the hydrogel presents the state of the sol at low temperature(it can flow),when the hydrogel is injected into the human body(?37 ?),The hydrogel solution changed into gel state and achieved a temperature sensitive controlled sol-gel transition.