New photosensitizers with optimal properties for photodynamic therapy (PDT)
Photosensitizers are used to treat various medical conditions including acne vulgaris, herpes, and cancer through the process of Photodynamic therapy (PDT). Once administered, the infected area is illuminated with a specific wavelength of light. During illumination the photosensitizer produces reactive oxygen species (ROS) which cause damage to any nearby cells in multiple ways including apoptosis and necrosis. An ideal photosensitizer has a high singlet oxygen quantum yield and a low dark toxicity. In order to search for a new photosensitizer with these desirable traits computer-aided molecular design (CAMD) was used. Nine different known photosensitizers were used to create quantitative structure-property relationships (QSPR's) based on their dark toxicity. Linear regression was then used to create correlations for three properties which were molar extinction coefficient, singlet oxygen quantum yield, and dark toxicity. The chemicals were then broken down into moieties and reconstructed using optimization formulation and solved using the Tabu Search algorithm to give new photosensitizer molecules with desired properties.