Developing a molecular level understanding of photodynamic therapy using femtosecond pump-probe spectroscopy

光动力疗法（PDT）使用光激活药物来治疗从癌症到年龄相关性黄斑变性和细菌感染等疾病。它基于这样一个概念：一种被称为光敏剂的无毒化学物质优先定位于目标部位，然后被通常由光纤传递的光激活，因此对周围健康组织的损害最小。光的吸收触发一系列光物理和光化学过程，产生活性氧，破坏癌细胞、新生血管或细菌。光敏剂的选择、药物-光时间间隔、药物剂量和光通量可以作为可调参数，针对特定的PDT进行优化。本提案的目的是在分子水平上详细了解PDT的基本光物理、光化学和光生物学。如果我们要发展从第一性原理出发设计用于特定治疗的高效光敏剂的能力，这种理解是必不可少的。

Photodynamic therapy (PDT) uses light-activated drugs to treat diseases ranging from cancer to age-related macular degeneration and bacterial infections. It is based on the concept that a non-toxic chemical, referred to as a photosensitiser, is localised preferentially in the target site and is then activated by light, usually delivered by fibre-optics, so that there is minimal damage to surrounding healthy tissue. The absorption of light triggers a sequence of photophysical and photochemical processes that generate reactive oxygen species which destroy cancer cells, neovasculature or bacteria.The choice of photosensitiser, the drug-light time interval, drug dose and light flux can be treated as adjustable parameters, to be optimised for a particular PDT. The objective of this proposal is to develop a detailed understanding of the fundamental photophysics, photochemistry and photobiology of PDT at the molecular level. Such understanding is essential if we are to develop the capability to design efficient photosensitisers for specific treatments from first principles.