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Photodynamic Therapy Efficacy Enhanced by Dynamics: The Role of Charge Transfer and Photostability in the Selection of Photosensitizers
Author(s) -
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.
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201304202
Subject(s) - photodynamic therapy , selection (genetic algorithm) , photosensitizer , charge (physics) , dynamics (music) , chemistry , photochemistry , computer science , physics , artificial intelligence , organic chemistry , quantum mechanics , acoustics
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–O 2 interaction rate constant ( k D ) and the photosensitizer decomposition rate constant ( k d ), k D / k 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 k D ) must be tempered by photostability (low k 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.