聚酰胺-胺功能化修饰多壁碳纳米管及作为神经生长因子载体的性能

Functional modifications of multi-walled carbon nanotubes with polyamidoamine dendrimer and the properties for nerve growth factor vectors

目的:聚酰胺-胺(PAMAM)功能化修饰的多壁碳纳米管(MWCNTs)非共价接枝神经生长因子(NGF)制备碳纳米管神经生长因子(MWCNTs-NGF)复合物,考察复合物体外促进神经生长的活性。方法:羧基化碳纳米管(MWCNTs-COOH)和4代聚酰胺-胺(PAMAM-G4)通过共价交联法制备得到碳纳米管聚酰胺-胺(MWCNTs-PAMAM)复合物,利用扫描电镜(SEM)、透射电镜(TEM)、红外光谱(IR)、热失重分析(TG)对复合物进行表征,采用MTT法研究其对嗜铬细胞瘤细胞(PC12细胞)的毒性,以MWCNTs-COOH作对照。以MWCNTs-PAMAM作为载体,通过非共价接枝NGF制备MWCNTs-NGF复合物,采用TEM进行表征,研究MWCNTs-NGF对PC12细胞及鸡胚背根神经节(DRG)的作用评价其生物活性。结果:SEM、TEM、FTIR、TG结果证实PAMAM成功接到了MWCNTs上;分散性试验结果表明MWCNTs-PAMAM在水和PBS中具有更好的分散稳定性,细胞毒性试验结果表明PAMAM功能化修饰MWCNTs大大降低了MWCNTs的细胞毒性;TEM图表明NGF修饰到了MWCNTs-PAMAM表面;生物活性试验表明MWCNTs-NGF具有明显的促进PC12细胞细胞分化及促进DRG神经生长的作用。结论:PAMAM功能化修饰的MWCNTs具有更好的生物相容性;与MWCNTs-COOH-NGF复合物相比,MWCNTs-PAMAM-NGF复合物在促进PC12细胞细胞分化及促进DRG神经生长方面的作用更加明显。

OBJECTIVE To prepare the complex of the carbon nanotube nerve growth factor（MWCNTs-NGF）,multi-walled carbon nanotubes（MWCNTs） functionalized by polyamide-amine（PAMAM） non-covalent grafting of the nerve growth factor（NGF）,and to observe the activity of the complex to promote nerve growth in vitro.METHODS Carbon nanotubes of polyamic-amine（MWCNTs-PAMAM） complexes were prepared by covalent crosslinking with carboxylated carbon nanotubes（MWCNTs-COOH） and 4 generations of polyamic-amine（PAMAM-G4）,Scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,infrared spectroscopy（IR） and thermal gravimetric analysis（TG） were used to characterize the complexes,MTT assay was used to study the toxicity of complexes on pheochromocytoma cells（PC12 cells）,Taking MWCNTs-COOH controls.MWCNTs-PAMAM as a carrier,preparation MWCNTs-NGF complex was prepared through non-covalent grafting NGF,and characterized by TEM,research MWCNTs-NGF was studied on PC12 cells and chicken embryo dorsal root ganglion（DRG） to evaluate its biological activity.RESULTS The results of SEM,TEM,FTIR and TG confirmed that the PAMAM successfully received the MWCNTs;The dispersibility test results showed that MWCNTs-PAMAM had better dispersion stability in water and PBS;The results of cytotoxicity experiments showed that PAMAM functionalization of MWCNTs greatly reduced the cytotoxicity of MWCNTs;TEM images showed that NGF modification to the surface of MWCNTs-PAMAM;Biological tests showed that MWCNTs-NGF significantly promoted cell differentiation of PC12 cells and the growth of DRG neurons.CONCLUSION The modified PAMAM functionalized MWCNTs has better biocompatibility;Compared with MWCNTs-COOH-NGF complex,MWCNTs-PAMAM-NGF complex exerts more pronounced role in promoting cell differentiation of PC12 cells and in the promotion of growth of DRG neurons.