Study On Preparation And Properties Of Composite Fiber Membranes By Electrospinning

The composite fibers prepared by electrospinning have become hot points in the development of modern medical technology.In this paper,different kinds of composite fibers are prepared by electrospinning as tissue engeering and drug delivery.Poly(trimethylene carbonate)(PTMC),gelatin(Gt)and modified hydroxyapatite nanoparticles(OA-HA)are used to fabricate composite fibers to simulate human cartilage tissue.Poly(lactic acid)(PLLA),modified hydroxyapatite nanoparticles(OA-HA)and fluorescent molecular Rhodamine B(RhB)are used to fabricate core-shell structured fibers which can be used to simulate drug controlled release system.Firstly,PTMC/Gt,PTMC/Gt/HA and PTMC/Gt/OA-HA composite fiber scaffolds are prepared by electrospinning.They are applied to simulate the human cartilage tissue and repair the injured condylar chondrocytes.As a component of human bone,HA nanopaticles are good at inducing bone growth and conduction.But due to the interaction between HA nanoparticles,they are easier to agglomerate.When they are blended with polymers,they disperse unevenly and agglomerate easily.The morphology,physicochemical properties and biological properties of PTMC/Gt/HA composite fibers are greatly affected.Therefore,the surface modification of HA nanoparticles is carried out to improve the dispersibility and uniformity of nanoparticles.XRD and FTIR prove that the crystal structure and chemical properties of HA nanoparticles are still maintained after surface modification.The morphology of PTMC/Gt/OA-HA composite fibers is greatly improved,the fiber diameters are uniform and OA-HA nanoparticles are distributed on the fiber surface uniformly.Secondly,some testing methods are used to characterize the physical and chemical properties of these three kinds of composite fibers.It can be seen that the addition of HA nanoparticles and OA-HA nanoparticles can improve the hydrophilicity of PTMC/Gt composite fibers.PTMC/Gt/OA-HA composite fibers have a better mechanical property.Each component in composite fibers keeps their original chemical property.The biological test showed that PTMC/Gt composite fibers have a better cell adhesion in the first day,but PTMC/Gt/HA and PTMC/Gt/OA-HA composite fibers have a better cell proliferation and differentiation in the following days.As tissue repair is a long way,PTMC/Gt/HA and PTMC/Gt/OA-HA composite fibers have more excellent biological properties.Thirdly,the PLLA fibers containing fluorescent molecules RhB are prepared by traditional electrospinning(RhB/PLLA fibers)and emulsion electrospinning(RhB-PLLA fibers)respectively.CLSM shows the distribution of fluorescence molecular RhB in two kinds of fibers.It is showed that RhB distribute in the internal and external RhB/PLLA fibers and RhB only distribute in the RhB-PLLA fibers forming the nuclear layer.It can be concluded that the core-shell structured fibers ca n be prepared by electrospinning,and core-shell structure can be seen in all fibers by CLSM.Fourthly,on the basis of RhB-PLLA core-shell structured fibers,the different contents of OA-HA nanoparticles are added into the shells.Tensile and contact angle test show that the addition of OA-HA nanoparticles could improve the mechanical properties and hydrophilicity of RhB-PLLA fibers.More importantly,the degradation rate of OA-HA nanoparticles is faster than that of PLLA and the degradation of OA-HA nanoparticles can cause the surface defect on the fiber shells,RhB molecules will release from these surface defects.With the content of OA-HA nanoparticles increasing,the release rate of RhB molecules will accelerate.This phenomenon shows that the release rate of RhB can be controlled by the content of OA-HA nanoparticles.