Studies On The Preparation And Application As Drug Delivery Carrier Of PLA-PEG-PLA/SF Hydrogels

Hydrogel is an important format of silk fibroin (SF), which has been studied for manybiomedical applications, such as drug/growth factor sustained delivery systems, bonefilling materials and three-dimensional cell culture carriers. SF aqueous solution undergoesself-assembly into hydrogel, but the rate of gelation is too slow under physiologicallyrelevant solution conditions, greatly limiting its biomedical application. PLA/PEG blockcopolymers due to their thermo-sensitive sol-gel transition, controllable hydrophobicityand degradability, gain exceptional superiority in tissue engineering, especially in bonetissue engineering and growth factor release.PLA-PEG-PLA triblock copolymer solution was blended with SF solution toaccelerate the sol-gel transition of SF through the hydrophilic and hydrophobic interaction.The main goal of our article was to study this acceleration and the gelation mechanism.Then due to the advantages of triblock copolymer, the gelation time of PLA-PEG-PLA/SFblend hydrogel could be controlled by changing the blend ratio, the molecular weight andother influencing factors, which could be further applied as drug delivery carrier.In this article, we firstly synthesized and characterized three types of PLA-PEG-PLAtriblock copolymers; Through the studies on gelation kinetics and rheological properties,we analysed the controllable gelation time of PLA-PEG-PLA/SF blend solutions; Thenthrough the studies of structural and morphological changes in the process of gelation, wecombined the experimental results with the Gibbs free energy to explain the gelationmechanism; Finally, we studied the degradation of blend hydrogels in vitro, and itsapplication as two model drug (aspirin and indometacin) delivery carrier, providing theexperimental basis for its further study as in situ-forming hydrogels for drug/growth factorrelease in tissue engineering.