SINGLET OXYGEN IN BIOLOGICAL SYSTEMS

这项赠款的主要目标仍然是确定 分子第一激发单重态的性质 氧气-02（1 delta g）-在类似和模拟生物的介质中 环境. 该计划的组成部分是努力 表征和理解分子的光特性， 表现为光动力敏化剂，并检查的方式， 这些过程取决于介质。 使用的方法依赖于 在使用激光器产生各种光脉冲时， 激发光敏剂的波长和随后的 产生这些瞬态实体的O2（1 Δ g 利用计算机控制的动态吸收和排放 具有纳秒时间分辨率的分光光度法。 这些允许 测量的光谱和动力学特性的短- 活的光动力中间体。 一项新技术将被采用 涉及单个细胞中的时间分辨显微荧光光谱法。 下一阶段的调查领域包括： (i)四吡咯（卟啉，酞菁， 萘菁）和其他致敏剂，包括检查 结构，配位金属离子的存在， 聚集态、溶剂性质和介质 微观异质性 (ii)研究了DNA的嵌入作用和包封作用对DNA的影响。 合成聚合物和生物聚合物对敏化剂产率的影响 三重态，单线态氧的产率和发生 I型和II型光动力机制。 (iii)单线态氧生成效率的研究 在敏化剂的三重态猝灭期间。 这个， 环境对生产过程的影响， 提高我们对光动力学机制的认识。 (iv)细胞中单线态氧形成的演示 种群的光动力条件下和相关性的 屈服于破坏。

The major objective for this grant continues to be to characterize the properties of the first excited singlet state of molecular oxygen -02(1 delta g) - in media that resemble and model biological environments. Integral to this program are endeavors to characterize and understand the photoproperties of molecules that behave as photodynamic sensitizers and to examine the ways in which such processes depend upon the medium. The methodology used relies upon using lasers for producing pulses of light of various wavelengths for excitation of photosensitizers and subsequent generation of 02(1 delta g) of these transient entities are made using computer-controlled kinetic absorption and emission spectrophotometry with nanosecond time resolution. These allow measurements of the spectral and kinetic properties of the short- lived photo-dynamic intermediates. A new technique to be employed involves time resolved microspectrofluorimetry in individual cells. Investigative areas for the coming period include: (i) Photoproperties of tetrapyrrole (porphyrins, phthalocyanines, naphthalocyanines) and other sensitizers including examination of the effects of structure, presence of co-ordinated metal ion, aggregation state, solvent properties and medium microheterogeneity. (ii) The effects of intercalation by DNA and encapsulation with synthetic polymers and biopolymers upon the yields of sensitizer triplet state, the yields of singlet oxygen and the occurrence of Types I and II photodynamic mechanisms. (iii) A study of the efficiency with which singlet oxygen is formed during the quenching of triplet states of sensitizers. This, together vita the influence of environment on the process, will enhance our knowledge of photodynamic mechanisms. (iv) Demonstrations of the formation of singlet oxygen in cellular populations under photodynamic conditions and correlations of the yields with damage.