SINGLET OXYGEN IN BIOLOGICAL SYSTEMS

这笔赠款的主要目标仍然是 分子第一激发单重态的性质 氧-02(1增量g)-在类似和模拟生物的介质中 环境。这一计划的一个组成部分是努力 描述和理解分子的光特性 表现为光动力学感光剂，并检查 这些过程取决于媒介。所使用的方法依赖于 在使用激光器产生各种光脉冲时 光敏剂及其后续的激发波长 产生这些瞬变实体中的02(1增量g 利用计算机控制的动力学吸收和排放 纳秒时间分辨率的分光光度法。这些允许 短分子的光谱和动力学性质的测量 活的光动力中间体。将采用的一种新技术 涉及单个细胞的时间分辨显微荧光测定法。 未来一段时期的调查领域包括： (I)四吡咯(卟啉、酞菁、 和其他增感剂，包括检测 结构的影响，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)DNA插层和包埋的影响 合成聚合物和生物聚合物对敏化剂产率的影响 三重态、单线态氧的产额和单重态的发生 第一类和第二类光动力机制。 (三)单线态氧形成效率的研究 在敏化剂的三重态猝灭过程中。这, 把环境对这一过程的影响结合起来，就会 增强我们对光动力机制的认识。 (四)细胞内单线态氧形成的演示 光动力条件下的种群及其相互关系 会带来损失的产量。

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.