Correlation of Photosensitization and Binding Mode of Methylene Blue and DNA  

作　　者：LIU Tao ZHANG Feng CHEN Ping TANG Guo-Qing LIN Lie 

机构地区：[1]Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education), Institute of Modern Optics, Nankai University, Tianjin 300071

出　　处：《Chinese Physics Letters》2011年第1期115-118,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant Nos 60508004 and 60778043, and the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No 20060055024.

摘　　要：Binding of methylene blue （MB） and DNA, photosensitization of MB in DNA, and correlation of photosensiti- zation and binding mode are studied at different concentration ratios of DNA and MB. The absorption spectra indicate that the electrostatic binding is the main mode at low γ ratios （γ≤ 2）, while at high γ ratios （γ 〉 2） the intercalative binding is dominated. Mudies on dynamics of photosensitization formation of singlet oxygen （102） for MB in DNA are carried out by using＂ time-resolved technology. There are no obvious changes of the singlet oxygen lifetime and the triplet state MB molecule （MB3＋＊） lifetime at low ratios, they are about 4 μs and 1 μs, respectively. However, we could not obtain the 1 O2 lifetime and MB3＋＊ lifetime due to the great decrease of 1 O2 phosphorescence signals at high ratios. These results show that the photosensitization and binding mode of MB in DNA possess high correlation. When MB binds with DNA by electrostatic interaction, type-lI photosen- sitization of MB plays a major role in photodynamic effect, the damage of DNA probably could be ascribed to 1 O2. However, at high ratios, binding mode between MB and DNA turns to intercalative binding, which greatly weakens the type-Ⅱ photosensitization process. Charge transfer between MB and DNA possibly becomes the main damage mechanism.Binding of methylene blue （MB） and DNA, photosensitization of MB in DNA, and correlation of photosensiti- zation and binding mode are studied at different concentration ratios of DNA and MB. The absorption spectra indicate that the electrostatic binding is the main mode at low γ ratios （γ≤ 2）, while at high γ ratios （γ 〉 2） the intercalative binding is dominated. Mudies on dynamics of photosensitization formation of singlet oxygen （102） for MB in DNA are carried out by using＂ time-resolved technology. There are no obvious changes of the singlet oxygen lifetime and the triplet state MB molecule （MB3＋＊） lifetime at low ratios, they are about 4 μs and 1 μs, respectively. However, we could not obtain the 1 O2 lifetime and MB3＋＊ lifetime due to the great decrease of 1 O2 phosphorescence signals at high ratios. These results show that the photosensitization and binding mode of MB in DNA possess high correlation. When MB binds with DNA by electrostatic interaction, type-lI photosen- sitization of MB plays a major role in photodynamic effect, the damage of DNA probably could be ascribed to 1 O2. However, at high ratios, binding mode between MB and DNA turns to intercalative binding, which greatly weakens the type-Ⅱ photosensitization process. Charge transfer between MB and DNA possibly becomes the main damage mechanism.

关 键 词：Instrumentation and measurement Medical physics Biological physics 

分 类 号：O614.33[理学—无机化学] S511.035.3[理学—化学]