【摘要】 纳米材料与蛋白质等生物大分子的相互作用是纳米材料生物效应和安全性研究的重要基础。本实验利用荧光光谱、同步荧光光谱、圆二色谱(CD)等方法研究了四种结构特性不同的水溶性羧基化碳纳米管(long-SWCNTs-COOH,short-SWCNTs-COOH,DWCNTs-COOH,MWCNTs-COOH)与人血清白蛋白(human serum albumin,HSA)的相互作用。实验结果显示:四种水溶性羧基碳纳米管均能猝灭HSA的内源荧光,但猝灭能力有所不同,相同浓度下不同水溶性羧基化碳纳米管对HSA的荧光猝灭作用遵循如下规律:DWCNTs-COOH<MWCNTs-COOH<long-SWCTs-COOH<short-SWCNTs-COOH;四种碳纳米管对HSA的同步荧光光谱影响表明,MWCNTs-COOH的作用位点更靠近色氨酸(Trp)残基,而DWCNTs-COOH的作用位点更靠近酪氨酸(Tyr)残基,而long-SWCNTs-COOH和short-SWCNTs-COOH对两种氨基酸残基的作用无明显差别;在碳纳米管作用下,HSA的圆二色谱有微弱的变化,且与α-螺旋、β-折叠含量变化基本一致。结果表明,不同碳纳米管对HSA的荧光猝灭能力与它们的结构特性有关,两者作用过程中HSA构象基本不变,二级结构有微小变化,但无明显的剂量-效应关系。根据实验结果对可能的作用机制进行了讨论。更多还原

【Abstract】 The interaction between nanomaterials and biological macromolecules(including protein)is the important basis of biological safety assessments of nanomaterials.In this paper,the fluorescence spectroscopy,synchronous fluorescence spectroscopy and circular dichroism spectroscopy)were used to analyze the interaction between four water-soluble carboxyl carbon nanotubes(long-SWCNTs-COOH,short-SWCNTs-COOH,DWCNTs-COOH and MWCNTs-COOH)and human serum albumin.Results showed that the four water-soluble carboxylated carbon nanotubes could quench the intrinsic fluorescence of human serum albumin at different extents.Under the same concentration,the quenching ability of four carboxylated carbon nanotubes were in the order of DWCNTs-COOH<MWCNTs-COOH<long-SWCNTs-COOH<short-SWCNTs-COOH.The synchronous fluorescence spectroscopy of human serum albumin in the absence and presence of four carbon nanotubes indicated that the binding location of MWCNTs-COOH was close to tryptophan(Trp)residue and DWCNTs-COOH was close to the tyrosine(Tyr)residues while those of long-SWCNT-COOH and short-SWCNT-COOH have no significant difference to two amino acid residues.The four water-soluble carboxyl carbon nanotubes could cause slight changes of the CD spectra of human serum albumin as well as theα-helix andβ-sheet contents of human serum albumin.The above results indicate the fluorescence quenching effect of carbon nanotubes on human serum albumin was related to their structural properties.During the binding process,the human serum albumin conformation remained unchanged,and there were slight changes as to its secondary structure,but there is no obvious dose-response relationship could be observed.The mechanism was also discussed.更多还原