David Kessel

David Kessel has defined the subcellular mechanisms of photodynamic therapy, demonstrating that photosensitizer localization to mitochondria, endoplasmic reticulum, or lysosomes determines the mode of cell death through distinct apoptotic, necrotic, or autophagic pathways. His work on autophagy as both a survival and death mechanism in PDT-treated cells has identified combination strategies that enhance PDT efficacy. He is a foundational figure in understanding PDT photobiology at the cellular level.