Research Of Drug Nano-carriers And Hydrogels

Polymer science technology has been getting most attention from wide areas such as military,aerospace,medical and so on for a long time.With the development of polymer technology,the requirement for the polymer material and polymer integration technology has been enhanced.High efficiency,controllability,and selectivity are requirements for the integration of polymer.Therefore,click chemistry and controlled free radical polymerization become the essential approach for construct special structure polymer.It provides a platform to manufacture other materials as well.This paper did a research for the aspect of integrate and application of high graft density brush polymer and grafted hydrogel,The main results obtained in this thesis are as followed.1.Using the combination of RAFT polymerization and click chemistry,two stages of grafting side-chains produced brush polymers of PGMA-g-(PEG/PCL)with high grafting density.Firstly,PGMA with appropriate molecular weight and narrow distribute was obtained from RAFT polymerization as the backbone chain.Then azido and hydroxyl groups were introduced by opening epoxy rings of backbone chain with NaN3.Finally,through "graft-to" and "graft-from" methods,two grafting chains of PEG and PCL were introduced in proper order.This route can get a grafting density of almost 100%for the brush polymer.For "graft-to" method,PEG having a alkynyl at one terminal was clicked with N3 group of backbone chain,due to the high efficiency of click chemistry,where the results from NMR and IR analysis confirmed quite high grafting ratio.As for "graft from" method,the hydroxy groups of backbone chain initiated the cation ring-opening polymerization of CL using Sn(Oct)2 as catalyst.Because of the fast initiation and growth of cation ring-opening polymerization,PCL was grafted with the grafting efficiency of 100%based on NMR and FTIR analysis.To load the drug of DOX,brush polymer and DOX were mixed in the hydrophobic solvent with low boiling point.After rapid stirring the obtained solution in water,self-emulsifying latex was formed.After the natural evaporation to remove organic solvent and the dialysis in water to removing the unloaded DOX,the DOX-loading particles were obtained and had small size and narrow diameter distribution.The experiment of drug release found out that the DOX-loading particles released the drug efficiently.Due to the biocompatibility and biodegradability of grafted side chains,this research becomes meaningful for the research of biomedicine area.2.The influence of grafting PNIPAM chains on the thermal responsive behavior of PNIPAM hydrogel was investigated.Through free radical copolymerization with NIPAM as maim monomer,acryloyl-capped PEG at two ends as cross-linking reagent and GMA as functional monomer,PNIPAM hydrogel was obtained.In DMF,the hydrogel was swelled and azido groups were introduced through the ring-opening of epoxy groups by NaN3.After that,linear PNIPAM chains were grafted onto the hydrogel network through click reaction with alkynyl-capped PNIPAM.The thermal response of PNIPAM hydrogel with grafting PNIPAM chains was studied.