Photodynamic Therapy Efficacy Enhanced by Dynamics: The Role of Charge Transfer and Photostability in the Selection of Photosensitizers. Issue 18 (18th March 2014)

• Record Type: Journal Article
• Authors: Arnaut, Luis G.; Pereira, Mariette M.; Dąbrowski, Janusz M.; Silva, Elsa F. F.; Schaberle, Fábio A.; Abreu, Artur R.; Rocha, Luís B.; Barsan, Madalina M.; Urbańska, Krystyna; Stochel, Grażyna; Brett, Christopher M. A.
• Is Part Of: Chemistry. Volume 20:Issue 18(2014)
• Page Start: 5346
• Page End: 5357
• Publication Date: 2014-03-18
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201304202
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Progress in the photodynamic therapy (PDT) of cancer should benefit from a rationale to predict the most efficient of a series of photosensitizers that strongly absorb light in the phototherapeutic window (650–800 nm) and efficiently generate reactive oxygen species (ROS=singlet oxygen and oxygen‐centered radicals). We show that the ratios between the triplet photosensitizer–O₂ interaction rate constant (<italic>k</italic>_D) and the photosensitizer decomposition rate constant (<italic>k</italic>_d), <italic>k</italic>_D/<italic>k</italic>_d, determine the relative photodynamic activities of photosensitizers against various cancer cells. The same efficacy trend is observed in vivo with DBA/2 mice bearing S91 melanoma tumors. The PDT efficacy intimately depends on the dynamics of photosensitizer–oxygen interactions: charge transfer to molecular oxygen with generation of both singlet oxygen and superoxide ion (high <italic>k</italic>_D) must be tempered by photostability (low <italic>k</italic>_d). These properties depend on the oxidation potential of the photosensitizer and are suitably combined in a new fluorinated sulfonamide bacteriochlorin, motivated by the rationale.</p> </abstract>