脱氧核糖核酸（DNA）激发态动力学的实时探测与超快宽带光谱研究

项目名称： 脱氧核糖核酸（DNA）激发态动力学的实时探测与超快宽带光谱研究

项目编号： No.21473114

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 马晨生

作者单位： 深圳大学

项目金额： 84万元

中文摘要： 脱氧核糖核酸(DNA)激发态动力学是目前光物理、光化学研究领域中的热点和极具挑战性的课题。本项目拟结合超快宽带时间分辨荧光和超快宽带瞬态吸收并配合稳态光谱，对一系列具代表性的DNA模型聚体及天然DNA进行深入而系统的研究。通过直接捕捉激发态的特征指纹光谱，实时跟踪激发态光谱随时间的变化, 全面探测激发态的动态演化过程, 以确定各种可能弛豫通道的相互转换及对整个动力学过程的权重贡献; 通过比较，阐明碱基堆积、配对、DNA构型、组成、长度等因素对激发态的影响, 为指认激发态电子性质, 揭示激发态能量传递、电荷传递、质子传递及DNA结构对这些过程的调控与影响提供直接的实验证据，以澄清目前对DNA激发态的争论, 并丰富人们对DNA光物理及光化学过程的认识, 为从分子层面上揭示DNA的光稳定性、潜在光损伤及DNA在材料等方面的实际应用，提供直接的实验证据和坚实的基础。

中文关键词： 脱氧核糖核酸；激发态动力学；超快时间分辨光谱；瞬态吸收；时间分辨荧光

英文摘要： Excited state dynamics of deoxyribonucleic acid (DNA) represents a challenging area and one of the key research subjects in photophysics and photochemistry. In this proposal, we will use a combined ultrafast broadband spectroscopy of time-resolved fluorescence and transient absorption in conjunction with steady state methods to perform a systematic study on series of representative single-stranded and double-stranded DNA model compounds as well as natural DNAs. The broadband spectroscopic capacity joint with ultrafast time resolution serves as an ideal tool for revealing comprehensively spectral fingerprints of the involved transient excited state species. It also provides a direct way for real time monitoring temporal evolution of the excited state spectra, thereby enables a direct probe of various nonradiative channels, including excited state energy transfer, charge transfer, and proton transfer, that may possibly participate in the excited state deactivation. Comparison of results obtained for the selected systems will provide direct and explicit information for deciphering timescale and elementary steps of the excited state processes; allowing to access the structure-property relationship, in particular the sequence, composition, conformation and size dependence of the excited state dynamics, as well as to evaluate the role of inter-base interactions (i.e., stacking and pairing) in modulating dynamics of the varied decay channels. The successful implementation and accomplishment of this research will afford vitally important new experimental insights that should significantly enrich our knowledge of photo-excited DNAs, revealing at molecular level the origin of DNA photostability and possible cause of photodamage. The results of proposed work will enable to elucidate the current controversies on the nature and dynamics of DNA excited-states and also contribute to potential application of DNA in the area of functional biomaterials.

英文关键词： DNA;excited state dynamics;ultrafast time-resolved spectroscopy;transient absorption;time-resolved fluorescence