Preparation Of Modified Polylactic Acid Nanofibrous Scaffolds And Microsphere Scaffolds Using Amino Alcohols As Modifiers

In this paper,the hydrophilia of the polylactic acid(PLLA)was enhanced by ammonolysis reaction,and the modified polylactide nano-fiber scaffold and nano-fiber microsphere stent-graft were prepared by the thermally induced phase separation method.The influence of the concentration of modifier on the morphology and properties of the scaffold was investigated.First,ethanol amine aqueous solution was usd as modifier to enhance the hydrophilia of the polylactic acid.By adjusting the amount of the modifier and controlling the conditions of the process,ethanol amine modified polylactic acid nano fiber scaffold was successfully prepared.The effects of the reaction conditions,such as the concentration of ethanolamine,the time of ammonia reaction,the temperature of gelation and the proportion of solvent,on the structure of the modified polylactic acid nanofibers were discussed.By SEM analysis,modified polylactic acid fiber scaffold with excellent microstructure and good performance can be formed under the appropriate conditions of the process.The gelling temperature is an important factor that affect the formation of fibrous structure.With the increase of the gelling temperature,the scaffolds of nanofibers is more thin and the network structure is more uniform.The hydrophilia of the scaffold is enhanced with the increase of the concentration of modifier,which is in benefit to the adhesion of the cells.Second,3-amino-1,2 propylene glycol aqueous solution was usd as modifier to enhance the hydrophilia of the polylactic acid.By adjusting the amount of the modifier and controlling the conditions of the process,3-amino-1,2 propylene glycol modified polylactic acid nano fiber scaffold was successfully prepared.The effects of the reaction conditions,such as the concentration of 3-amino-1,2 propylene glycol,the time of ammonia reaction,the temperature of gelation and the proportion of solvent,on the structure of the modified polylactic acid nanofibers were discussed.By SEM analysis,modified polylactic acid fiber scaffold with excellent microstructure and good performance can also be formed under the appropriate conditions of the process.The hydrophilia of the scaffold is also enhanced with the increase of the concentration of modifier.Comparing with the first chapter,we found that the introduction of polyhydroxyl can further increase the hydrophilicity of nanofiber scaffolds.Finally,use ethanol amine aqueous solution as modifier,by adjusting the amount of the modifier and controlling the conditions of the process,modified polylactic acid nano fiber microsphere stent-graft was successfully prepared.The effects of the reaction conditions,such as the concentration of ethanolamine,the time of ammonia reaction,the temperature of gelation and the proportion of solvent,on the structure of the modified fiber microsphere scaffolds were discussed.By SEM analysis,modified polylactic acid microsphere scaffold with excellent microstructure and good performance can be formed under the appropriate conditions of the process.The drug loading performance of the microsphere scaffolds was studied,in which the loading of the hydrophilic drugs was increased.This further demonstrated the enhanced hydrophilia of the modified polylactic acid.