Investigation of isomeric tetra-cationic porphyrin activity with peripheral [Pd(bpy)Cl]+ units by antimicrobial photodynamic therapy.

Abstract In this work, we first report the antimicrobial photoinactivation using tetra-cationic porphyrins with peripheral palladium(II) complexes against bacterial strains. Two different isomeric Pd(II)-porphyrins were used and applied in PDI experiments in the strains Gram negative bacilli Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa and a Gram positive cocci Staphylococcus aureus. All experiments are conducted with adequate concentration (without aggregation) of photosensitizer under white-light irradiation over 2 h showed that the most effective PS caused a significative reduction in the concentration of viable bacteria. The present results show that porphyrin with positively charge at meta position (3-PtTPyP) are more efficient photosensitizer against bacteria strains. In this way, tetra-cationic porphyrins might be promising antibacterial PDI agents with potential applications in medical clinical cases.