共价功能化对单壁碳纳米管产生DNA损伤和活性氧的影响研究

Effect of Covalent Functionalization on DNA Cleavage Activity and ROS Formation of Single-Walled Carbon Nanotubes

以质粒DNA评价法表征了不同程度共价功能化单壁碳纳米管(SWNTs)的生物毒性,并在近红外-可见光光谱、拉曼光谱和活性氧(ROS)表征的基础上研究了共价功能化对其物理结构和化学活性的影响.结果表明,共价功能化增强了碳纳米管对质粒DNA的损伤程度,3种不同类型的碳纳米管对DNA损伤的强度为羧基功能化SWNTs(SWNT-COOH)>聚乙二醇功能化SWNTs(SWNT-PEG)>非共价功能化SWNTs(uSWNTs).随着共价功能化程度的加深,碳纳米管表面石墨晶格的sp2结构受损程度逐渐增高,以致使其反应活性增大.共价功能化后SWNTs可作为电子转移中间体将NADH中的电子转移至O2并生成ROS从而对DNA造成损伤.

Biotoxicity of selected covalent functionalizaed single-walled carbon nanotubes（SWNTs） was investigated by plasmid DNA cleavage assay.The effect of covalent functionalization on the physical structural and chemical activity of SWNTs was also studied by Vis-NIR spectroscopy,Raman spectroscopy and ROS assay.The DNA cleavage intensity was promoted by covalent functionalization,and the intensity of DNA damage caused by the three types of carbon nanotubes in a descending order was found to be carboxylated SWNTs（SWNT-COOH）〉polyethyleneglycol-lated SWNTs（SWNT-PEG）〉uncovalent functionalized SWNTs（uSWNTs）.SWNTs were efficient intermediate to trigger electron transfer from electron donor to O2 in dark condition which lead to superoxide radical（O·-2） formation.The electron transfer intensity caused by selected SWNTs was also SWNT-COOH〉SWNT-PEG〉SWNTs.The reason is that defect sites which changed from sp2-hybridized carbon atom on the side wall of carbon nanotubes were more reactive than the perfect ones.