光谱法研究EGCG-Cu(Ⅱ)与ctDNA的相互作用

研究了EGCG-Cu(Ⅱ)-ctDNA系统的荧光光谱，电子吸收光谱和共振光散射光谱(RLS)。与EGCG-Cu(Ⅱ)二元配合物比较，EGCG-Cu(Ⅱ)-ctDNA三元体系光谱显示以下特征：(1)荧光光谱的发射位置没有变，荧光强度显著增强，并且三元体系的荧光强度随着DNA浓度增大而增大。在适宜的条件下，Cu(Ⅱ)-EGCG 配合物有望成为检测ctDNA的荧光探针;(2)电子吸收光谱有明显的增色效应;(3)共振光散射强度也增强。三种光谱的特征显示，EGCG-Cu(Ⅱ)配合物与核酸之间主要依靠插入作用和静电引力结合。由于配合物的插入，使系统的荧光强度增强，而静电作用使其电子吸收光谱和共振光散射光谱产生增色效应。酸度和离子强度对三元系统荧光强度的影响也进行了实验和讨论。

Interaction of ctDNA and EGCG-Cu(Ⅱ) Complex

The fluorescence spectra, absorption spectra and resonance light scattering (RLS) spectra of EGCG-Cu((II) complex with nucleic acid were studied. Compared with the spectrum of EGCG-Cu(II), the spectrum of EGCG-Cu(II)-DNA system showed the following features: (1) in the fluorescence spectra, the peak did not shift, but the fluorescence intensity was enhanced and was proportional to the concentration of DNA. Under suitable conditions, EGCG-Cu(II) promised to be a probe for detecting DNA; (2) Absorption spectra of EGCG-Cu(II)-DNA system showed hyperchromicity; and (3) RLS of EGCG-Cu(II)-DNA system was enhanced also. A mechanism was suggested that the combination of nucleic acid and EGCG-Cu(II) complex was caused by intercalation and electrostatic force. An intercalation interaction between EGCG-Cu(II) and DNA enhanced the fluorescence intensity. Hyperchromicity of absorption spectra and RLS occurred because of electrostatic force. The effects of acid and ionic strength on fluorescence intensity were also discussed.