Photokinetics and subcellular localizations of porphyrin sensitizers used in photodynamic therapy

Porphyrin photosensitizers (used in Photodynamic Therapy) were studied to investigate their photokinetics and subcellular localization. Verteporfin photobleaching kinetics were examined via optical trapping of sensitizer loaded DOPC (dioleoyl phosphatidylcholine) liposomes to determine oxygen dependency, size and cholesterol/sphingomyelin effects. Intracellular sensitizer localization was studied through fluorescent imaging of Lemuteporfin and Verteporfin introduced to red fluorescent protein (RFP) transfected fibroblast cells (CV-1). FRET images were examined to determine preferential localization to RFP targeted organelles (mitochondria and endoplasmic reticulum). Apoptosis assays were implemented after irradiation thereby examining the effectiveness of sensitizers to cause cell death through 1O2 generation.;Verteporfin photobleaching kinetics were found to be fastest in DOPC/cholesterol/sphingomyelin vesicles and CV-1 cells. FRET studies showed apparent co-localization of RFP and either sensitizer. Subcellular sensitizer seemed to localize more readily in mitochondria targeted cells to result in brighter images. Apoptotic activity was confirmed through apoptosis assays with no indication of superior apoptosis causing sensitizer.