LI-COR Biosciences, Biotechnology's video: What is Photodynamic Therapy

Photodynamic therapy (PDT) has been explored extensively in experimental oncology, ophthalmology, and dermatology. The core components of PDT are a prescribed light source, a light-sensitive chemical (photosensitizer), and molecular oxygen. Upon exposure to the prescribed light source, the photosensitizer coverts molecular oxygen into a highly reactive form (singlet oxygen). Watch this video portraying the actions of untargeted and targeted PDT. Left Panel: In untargeted PDT, photosensitizers (yellow circles) can accumulate in diseased as well as healthy tissues. Following light treatment, the photosensitizers can cause undesired off-target damage. Right Panel: In targeted PDT, photosensitizers (orange circles) are stably attached to biomolecules that specifically recognize diseased tissue. The biomolecules enable the photosensitizers to accumulate in diseased tissues and avoid healthy tissues, thereby reducing undesired off-target damage following light treatment. For more information, visit http://www.licor.com/PDT