Influence Of Oxygen Tension On Singlet Oxygen Luminescence And Photosensitizer Photobleaching

Photodynamic therapy (PDT) utilizes a photosensitizer, light with an appropriate wavelength and tissue oxygen to selectively destroy the target tissue. As an essential component in PDT, the availability of molecular oxygen is extremely important for the generation of singlet oxygen (’02) and other reactive oxygen species, which directly determining the therapeutic outcomes. The paper summaries the current available techniques for measuring tissue oxygen, and the strengths and limitations of each methodology will be discussed in detail. In particular, the recent emerging optical techniques for non-invasively monitoring tissue oxygen are highlighted, which holds the great promise for clinical use. Moreover, time-resolved1O2luminescence and photosensitizer photobleaching have been monitored in solution at different oxygen tension, and the relation between1O2luminescence and photosensitizer photobleaching, and the connection between the rate of photobleaching and the population of cumulative1O2. The obtained results indicate that the oxygen tension during photosensitization has significant impact on the1O2luminescence and the photobleaching of photosensitizer.