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dc.contributor.authorCosta, Dora C. S.pt_PT
dc.contributor.authorGomes, Maria Clarapt_PT
dc.contributor.authorFaustino, Maria A. F.pt_PT
dc.contributor.authorNeves, Maria G. P. M. S.pt_PT
dc.contributor.authorCunha, Ângelapt_PT
dc.contributor.authorCavaleiro, José A. S.pt_PT
dc.contributor.authorAlmeida, Adelaidept_PT
dc.contributor.authorTomé, João P. C.pt_PT
dc.description.abstractPhotodynamic inactivation (PDI) is an efficient approach against a wide range of microorganisms and can be viewed as an alternative for the treatment of microbial infections. In this work we synthesized "first" and "second" generation photosensitizers (PSs), the tetra-cationic porphyrin and the new penta-cationic chlorin , respectively, and evaluated their efficiency against two antibiotic resistant bacterial strains, Staphylococcus aureus and Pseudomonas aeruginosa. The PS was obtained in very good yield by an easy synthesis method. The PDI studies were performed in parallel with 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetra-iodide (), a widely studied PS in PDI, and the obtained results were compared. Two different light ranges were used: white light (400-800 nm) and red light (530-800 nm) delivered at a fluence rate of 150 mW cm(-2). The results show that both strains, even though antibiotic resistant, were efficiently inactivated by the three PSs, chlorin being the most effective. For the Gram positive bacterium S. aureus a 7.0 log reduction was observed after 5-10 min of irradiation, at a concentration of 0.5 μM, whereas for the Gram negative P. aeruginosa, similar photoinactivation occurred at a higher PS concentration (10 μM) and after a longer irradiation period (30 min). The synthetic chlorin can be regarded as promising for the treatment of bacterial infections under red light, which penetrates deeper in living tissues. The results of this study open the possibility to prepare a new series of chlorin-type derivatives to efficiently photoinactivate Gram (+) and (-) antibiotic resistant bacteria. The efficient PDI with the chlorin indicates high potential for the use of a scaffold in the preparation of new generation PSs based on cationic chlorin derivatives.pt_PT
dc.description.sponsorshipThanks are due to FCT and FEDER for funding the QOPNA unit (project PEst-C/QUI/UI0062/2011), CESAM and the Portuguese National NMR Network, also supported by funds from FCT. Thanks are also due to Graça Ribeiro from the Microbiology Laboratory of HUC (Hospitals of the University of Coimbra) for providing the clinical bacterial strains. This work had financial support from project PTDC/QUI/65228/2006. D.C.S.C. acknowledges BI grants BI/UI55/5571/2011 and BI/UI55/5471/2012; M.C.G also acknowledges BI grant BI/UI55/4856/2010.pt_PT
dc.publisherRoyal Society of Chemistrypt_PT
dc.titleComparative photodynamic inactivation of antibiotic resistant bacteria by first and second generation cationic photosensitizerspt_PT
degois.publication.titlePhotochemical & photobiological sciencespt_PT
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