Ruthenium(II) Polypyridyl Complexes as Photosensitizers for Antibacterial Photodynamic Therapy:A Structure- Activity Study on Clinical Bacterial Strains

摘要

As agrowing public health concern, the worldwide spreadof antimicrobial resistance urges the development of new thera- pies. Antibacterial photodynamic therapy(a-PDT) maybeanal- ternative to conventionalantibiotic therapy.Herein we report the synthesis and characterization of seven originalreactive oxygen species(ROS)-producing ruthenium(II)polypyridyl com- plexes. These are part of acollection of 17 derivativesvarying in terms of the nature of the substituent(s), molecular symme- try,electrical charge, and counterions. They were characterized by considering 1) their physical properties (absorption coefficient at irradiation wavelength, ~1 O2 generation quantum yield, luminescence) and2)their antibacterial activity in aseries of photodynamic assaysusing Gram-positive and Gram-negative bacteria of clinical relevance. The results unveiled somestruc- ture-activity relationships:one derivativethat combines multi- ple beneficial features for a-PDT was effective against all the bacteria considered,regardless of their Gram status,species, or antibiotic resistance profile. This systematic study could guide the design of next-generation ruthenium-basedcomplexes for enhanced antibacterial photodynamic strategies.