Cellular biomolecules near the photosensitizer

The term "cellular biomolecules near the photosensitizer" refers to the collective group of endogenous molecules—including lipids, proteins, and nucleic acids—that are situated within the immediate diffusion radius of a photosensitizing agent during photodynamic therapy (PDT) (Castano et al., 2004). In PDT, a photosensitizer is administered and subsequently activated by a specific wavelength of light, resulting in the generation of reactive oxygen species (ROS), most notably singlet oxygen (Agostinis et al., 2011). Because singlet oxygen is highly reactive and has an extremely short half-life, its diffusion distance is restricted to approximately 10 to 100 nanometers from the site of generation (Moan & Berg, 1991). Consequently, the therapeutic effect is highly localized, causing oxidative damage such as lipid peroxidation and protein denaturation only to those biomolecules in the photosensitizer's immediate subcellular environment, such as the mitochondria or plasma membrane. This localized destruction triggers various cell death pathways, including apoptosis and necrosis, making it an effective strategy for treating localized cancers and dermatological conditions (Dougherty et al., 1998).

Other names

PDT molecular targetsEndogenous substrates of singlet oxygenSubcellular biomoleculesCellular components of photodynamic action

Photosensitizers absorb light energy to produce reactive oxygen species (ROS), primarily singlet oxygen, which oxidatively damage nearby biomolecules within a limited diffusion radius (approx. 20-100 nm), leading to localized cell death.