Preparation And Performance Of Chitosan Modified PLGA Nanofibers Based On Electrospinning

Electrospining is an effective method to yield continues fiber of nanometer tomicrometer scale. The fibrous membrane with large surface to volume ratio, interconnectedpores and high porosity, is similar to extracellular matrix and, thus has broad application inbiomedical fields. In this paper, the PLGA entrapped chitosan electrospun nanofibers,electrospun chitosan grafted PLGA nanofibers and coaxial PLGA/CS electrospun nanofibersare investigated systematically in tissue engineering and drug release. The main contents areas followed:Firstly, the entrapment technology is used for surface modification of PLGA electrospunnanofibers with chitosan. The influence of concentration of2,2,2-thifluoroethanol aqueoussolution, swelling time and concentration of entrapment polymer on entrapment areinvestigated to confirm the best conditions and obtain the chitosan entrapment PLGAnanofibers. The water contact angle and protein absorption test shows the higherhydrophilicity of modified PLGA nanofibers and controlled the protein absorption onto thenanofibres. The mechanical property of PLGA nanofibers is improved through entrapment.Secondly, chitosan grafted PLGA (CS-graft-PLGA) nanofibres produced via theelectrospinning technique. CS was grafted onto the surface of PLGA using the cross-linkagents reacted with the reactive carboxyl group of PLGA after the alkali treatment. The CSgrafting ratios of the electrospun CS-graft-PLGA nanofibers were about2.43%,4.34%,16.97%and39.40%after cross-linked for12h,16h,20h and24h, respectively. Theelectrospun CS-graft-PLGA nanofibres were significantly uniform and highly smooth withoutthe occurrence of bead defects, even at high CS grafting ratio. The grafted CS improved thehydrophilicity and controlled the protein absorption onto the nanofibres. Moreover, theelectrospun CS-graft-PLGA nanofibres maintained the good mechanical property of the purePLGA nanofibres. The CS grafting can be conducive to induce higher degradation rate ofPLGA.Finally, the different shell thickness coaxial PLGA/chitosan nanofibers were fabricatedby the coaxial electrospinning technique via changing the shell solution feed rate. TEMstudies indicated the core/shell structure of the composite nanofibers fabricated. SEM andFT-IR studies shows the morphology and chemical structure of the coaxial nanofibers. Thewater contact angle and protein absorption test shows the higher hydrophilicity of coaxialPLGA/chitosan nanofibers and controlled the protein absorption onto the nanofibres. Meanwhile coaxial electrospun fenbufen (FBF)-loaded PLGA/CS nanofibrous are producedand their drug release characteristics are further investigated. The further investigation findsthat coaxial FBF-loaded PLGA/CS nanofibrous could control the process of drug release andinhibit the burst release of the drug effectively.