Antimicrobial Photodynamic Therapy and Photodynamic Inactivation, or Killing Bugs with Dyes and Light—A Symposium‐in‐Print

In antimicrobial photodynamic therapy, the photosensitizer (PS) in its ground singlet state absorbs light to give the excited singlet state that can transition to the long-lived triplet state. This PS triplet may undergo energy transfer (Type 2) or electron transfer (Type 1) to oxygen to form reactive oxygen species (singlet oxygen and/or hydroxyl radicals) that can kill both Gram-positive and Gram-negative bacteria and fungi. Infections in animal models can also be treated.