| Porous nanomaterials have many excellent characteristics,such as high porosity,high adsorption,high surface activity and high specific surface area,due to the structure of channels,holes and gaps on the surface or inside of them.They have shown great application prospects in chemical engineering,electronic engineering,environmental science,biomedicine,energy and so on.In this paper,polylactic acid(PLA)/tea polyphenols(TPs)porous nanofibers with different structures were prepared by different electrospinning methods,and the effects of electrospinning parameters,such as solvent ratio,solute concentration,solution concentration and spinning speed,on the morphologies,adsorption performances,antibacterial and drug release properties of PLA/TPs nanofibers were investigated.Firstly,porous and non-porous PLA/TPs nanofibers were prepared by single-needle electrospinning.The effects of TPs content and solvent ratio on the morphologies of the electrospun PLA/TPs nanofibers were studied,and the nanofibers were used in the adsorption of silver ions in waste water.Through a series of characterizations and analyses for the electrospun PLA/TPs nanofibers before and after adsorption of silver ions,such as scanning electron microscopy(SEM),fourier transform infrared spectroscopy(FTIR),energy dispersive spectrometer test(EDS)and atomic absorption spectrophotometer,the results showed the porous PLA/TPs nanofibers exhibited better adsorption property of silver ions,and the nanofibers with silver ions have good bactericidal and antibacterial properties against Escherichia coli.In addition,the drug release properties of porous PLA/TPs nanofibers without silver ions were investigated.It was found that the release properties of TPs from the nanofibers were not ideal due to burst release over a short period of time.In order to reduce the burst release of drug,the TPs loaded porous core-shell nanofibers were prepared by coaxial electrospinning,and their morphologies,structures and properties were characterized by a combination of SEM,TEM,FTIR,contact angle(CA)measurements and et al.The effects of spinning parameters,such as the concentration of core and shell solution,the solvent ratio of shell solution and the flow rates of core and shell solution,on the morphology and structure of the nanofibers were investigated,and the optimal spinning parameters for the fabrication of TPs loaded porous core-shell nanofibers were determined.PLA shell solutions were prepared with 8 wt%by using mixture of solvents DCM and DMF with weight ratios of 9:1,and the flow rate of shell solution was maintained at a constant rate of 2mL/h.PEO core solutions were prepared with 7 wt%by using DMF as the solvent,and 0.05g TPs were added into lOg core solution,the flow rate of core solution was set to 0.2mL/h.Meanwhile,the obtained nanofibers had obvious porous core-shell structure,and the diameter distribution of the nanofibers was uniform.Finally,the cumulative drug release rate of TPs from the porous core-shell nanofibers were investigated and compared with that of PLA/PEO/TPs porous nanofibers.According to the drug release curve of TPs,after 21 hours the TPs release of porous core-shell,nonporous core-shell,PLA/PEO nanofibers loaded with TPs reached 32%,37%and 66%,respectively.It could be seen that the initial burst release of TPs was prevented by core-shell nnanofibers compared to non-core-shell nanofibers,and the porous structure of the core-shell nanofibers could reduce the burst release and improve the drug slow release property. |
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