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

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【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

2、力学实验机,超高阻微电流测量仪,材料体外降解等手段进行表征。结果表明：PLA/MWCNTs导电复合纤维直径均匀、形貌良好；MWCNTs在复合纤维内部分散均匀；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行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

3、镜,荧光显微镜和扫描电子显微镜对细胞的生长进行了表征。结果表明：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

4、转换红外分析仪(FTIR)对MWCNTs/GTP进行表征,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)等手段进行了表征。结果表明：茶多酚(GTP)成功粘附在了MWCNTs表面;PCL/MWCNTs复合电纺纤维直径分别较宽,形貌良好,MWCNTs在纤维内部分散均匀；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MWCNTs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

5、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-walled carbon nanotubes (PCL/MWCNTs) composit

6、e 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, electrical conductivity and good biocompatibil

7、ity. 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), universal mechanical testing machine, surface

8、 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 composite fiber; mechanical properties of comp

9、osite 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 threshold was existed when content of MWCNT

10、s 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 different sizes of direct current stimulation (50

11、,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 that: without electrical stimulation, obsteo

12、blast 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 stimulation of 50 and 100A can promote the gr

13、owth 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) no matter for random oriented or aligned fi

14、brous 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 in vitro and cell experiment (OB, A549, Hep

15、 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 diameter and good morphology, MWCNTs dispe

16、rsed 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 composite fibrous scaffo

17、ld containing GTP could effectively control the burst release of GTP compared to pure PCL scaffold with GTP, and they had minor cytotoxic to normal obsteoblast and inhibition to tumor cells (A549 and Hep G2).【关键词】多壁碳纳米管 聚乳酸 聚己内酯 静电纺丝 组织工程支架 药物控制释放【英文关键词】MWCNTs PLA PCL electrospinning tissue engineer

18、ing scaffold drug controlled release【目录】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摘要7-9Abstract9-10第1章 绪论15-261.1 前言151.2 静电纺丝体系15-171.2.1 静电纺丝体系的历史15-161.2.2 静电纺丝原理及影响因素16-171.3 电纺纤维的材料及结构17-221.3.1 电纺纤维的材料17-191.3.2 电纺纤维的结构19-221.4 电纺纤维与组织工程支架22-231.5 电纺纤维与药物控制释放231.6 电纺纤维的其他应用23-241.7 本文研究目的、主要内容与创新点24-261.7.1 本

19、文研究目的24-251.7.2 本文研究主要内容251.7.3 本文研究主要创新点25-26第2章 导电PLA/MWCNTs复合纤维的制备与表征26-382.1 前言262.2 实验材料及设备26-272.2.1 实验材料26-272.2.2 实验设备272.3 导电PLA/MWCNTs复合纤维膜制备27-282.3.1 MWCNTs酸化与纺丝液27-282.3.2 静电纺丝282.4 导电PLA/MWCNTs复合纤维膜表征28-292.4.1 SEM282.4.2 TEM282.4.3 拉伸力学测试28-292.4.4 表面电阻率测试292.4.5 体外降解表征292.5 数据统计学处理29

20、-302.6 结果与分析30-372.6.1 表面形貌分析30-322.6.2 内部结构分析32-332.6.3 力学特征分析33-342.6.4 表面电阻率分析34-352.6.5 体外降解分析35-372.7 本章小结37-38第3章 微电流刺激对导电PLA/MWCNTs纤维上成骨细胞生长影响38-473.1 前言383.2 实验材料及设备38-393.2.1 实验材料383.2.2 实验设备38-393.3 成骨细胞体外培养39-403.3.1 器材及细胞专用液体393.3.2 材料灭菌和预处理39-403.3.3 细胞接种与微电流刺激实验403.4 成骨细胞体外表征40-413.4.1 Alamar blue40-413.4.2 光学显微镜413.4.3 荧光显微镜413.4.4 扫描电子显微镜(SEM)413.5 结果与分析41-463.5.1 细胞增殖结果分析41