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1、多壁碳纳米管论文：可降解高分子-碳纳米管复合电纺纤维的制备及其性能研究 作者： 日期：多壁碳纳米管论文：可降解高分子/碳纳米管复合电纺纤维的制备及其性能研究【中文摘要】本论文使用静电纺丝法制备了无规取向和定向导电聚乳酸碳纳米管(PLA/MWCNTs)复合纤维支架和载药(茶多酚)的聚己内酯碳纳米管(PCL/MWCNTs)复合纤维支架。其中,所采用的聚乳酸和聚己内酯高分子可生物降解,无毒,具有良好的生物相容性；多壁碳纳米管(MWCNTs)具有优异的力学性能、导电性及良好的生物相容性。因此,可以预见,我们制备的纤维支架在组织工程和药物控制释放方面具有广阔的应用前景。首先,对于PLA/MWCNTs导电
2、复合电纺纤维支架,我们使用扫描电子显微镜(SEM),透射电子显微镜(TEM),万能材料力学实验机,超高阻微电流测量仪,材料体外降解等手段进展表征。结果说明：PLA/MWCNTs导电复合纤维直径均匀、形貌良好；MWCNTs在复合纤维内局部散均匀；复合纤维力学性能得到大幅提高,且定向纤维支架比无规取向纤维支架力学性能强；在MWCNTs含量为3%时,有电渗阈值现象；PLA/MWCNTs导电复合电纺纤维体外降解速度受MWCNTs含量的影响显著。其次,我们使用自制装置对成骨细胞在导电PLA/MWCNTs纤维支架上的生长进展了不同大小的微直流电刺激(50,100,200A),以研究导电复合纤维的形貌特征和
3、电刺激对成骨细胞体外生长的协同影响。我们分别使用Alamar blue法,普通光学显微镜,荧光显微镜和扫描电子显微镜对细胞的生长进展了表征。结果说明：没有电刺激时,成骨细胞在无规取向纤维支架上向四周均匀生长,在定向纤维支架上沿纤维取向生长,且细胞在定向纤维支架上增殖数量要好于无规取向纤维支架,且MWCNTs含量为3%时,细胞生长情况最好；50,100A电刺激都能促进成骨细胞的生长,100A电刺激最有利于细胞生长,200A电刺激导致成骨细胞大量死亡；成骨细胞在电刺激作用下,沿电流方向生长(100A电刺激效果最好),无规取向导电纤维支架上的细胞在电刺激作用下形貌变得狭长,定向纤维支架上细胞长宽比也
4、有所提高。最后,对于载药(茶多酚)PCL/MWCNTs复合电纺纤维支架,首先采用傅里叶转换红外分析仪(FTIR)对MWCNTs/GTP进展表征,然后采用扫描电子显微镜(SEM),透射电子显微镜(TEM),激光共聚焦显微镜,万能力学测试仪,体外降解,体外药物控制释放,细胞实验(OB, A549, Hep G2)等手段进展了表征。结果说明：茶多酚(GTP)成功粘附在了MWCNTs外表;PCL/MWCNTs复合电纺纤维直径分别较宽,形貌良好,MWCNTs在纤维内局部散均匀；复合纤维支架力学性能由于MWCNTs而增强,由于小分子药物GTP而下降；载药PCL/MWCNTs复合纤维支架体外降解速度受MWC
5、NTs和GTP含量的影响较大；载药PCL/MWCNTs复合纤维支架相对于纯PCL载药支架来说,能有效降低GTP的突释现象,且对正常细胞毒性较小,对肿瘤细胞生长有一定的抑制作用。【英文摘要】In this paper, the conductive poly(d,l-lactide)/multi-walled carbon nanotubes (PLA/MWCNTs) composite fibrous scaffolds with two morphologies (random oriented and aligned fiber) and polycaprolactone/multi-wa
6、lled carbon nanotubes (PCL/MWCNTs) composite fibrous scaffold containing green tea polyphenols (GTP) were successfully fabricated by electrospinning. The biodegradable materials we selected PLA and PCL are non-toxic and have excellent biocompatibility; MWCNTs has excellent mechanical properties, ele
7、ctrical conductivity and good biocompatibility. Therefore, it is foreseeable that the fibrous scaffolds we prepared have broad application in tissue engineering and drug controlled release.Firstly, the characterization of scanning electron microscopy (SEM), transmission electron microscopy (TEM), un
8、iversal mechanical testing machine, surface resistivity testing, materials degradation in vitro were given to conductive PLA/MWCNTs composite fibrous scaffold. Results showed that:the conductive PLA/MWCNTs composite fiber had uniform diameter and good morphology; MWCNTs dispersed well within the com
9、posite fiber; mechanical properties of composite PLA/MWCNTs fibers increased significantly compared with pure PLA fibers, and the mechanical properties of aligned composite fibrous scaffold were better than random oriented fibrous scaffold when content of MWCNTs was the same; electrical percolation
10、threshold was existed when content of MWCNTs was 3%; in vitro degradation of PLA/MWCNTs composite fibrous scaffold was affected significantly by MWCNTs.Secondly, in order to study the coordinate effect of micro-current stimulation and morphology of scaffold on the growth of obsteoblast, three differ
11、ent sizes of direct current stimulation (50,100,200A) was applied to the obsteoblast through conductive PLA/MWCNTs fibrous scaffold by a home-made device. The characterization of alamar blue, optical microscope, fluorescence microscope and scanning electron microscopy were executed. Results showed t
12、hat: without electrical stimulation, obsteoblast on random oriented fibrous scaffold grew surroundly, while obsteoblast on aligned fibrous scaffold grew along the orientation of aligned fibers and the cell proliferation was better especially when content of MWCNTs was 3%; additionally, electrical st
13、imulation of 50 and 100A can promote the growth of osteoblasts, especially for 100A, while electrical stimulation of 200A led to massive death for osteoblasts; at last, the electrical stimulation caused obsteoblast grown along the direction of the direct current (the effect of 100A was best of all)
14、no matter for random oriented or aligned fibrous scaffold.Finally, the characterization of fourier transform infrared analyzer (FTIR), scanning electron microscopy (SEM), laser scanning confocal microscope, universal mechanical testing machine, materials degradationin vitro, drug controlled release
15、in vitro and cell experiment (OB, A549, Hep G2) were applied to PCL/MWCNTs composite electrospun fibrous scaffold containing GTP. Results showed that:GTP successful adhere to the surface of MWCNTs by noncovalent interactions; PCL/MWCNTs composite electrospun fibrous scaffold had wide distribution of
16、 diameter and good morphology, MWCNTs dispersed well within the fiber; PCL/MWCNTs composite fibrous scaffold possessed enhanced mechanical properties due to MWCNTs although it was weaken by GTP; in vitro degradation of PCL/MWCNTs composite fibrous scaffold was affected by MWCNTs and the content of GTP; the PCL/MWCNTs
