Photodynamic inactivation of Pseudomonas aeruginosa bacterial biofilms using new polycationic photosensitizers

Abstract

The treatment of infected, long-term, non-healing, complicated wounds of the skin and mucosa, trophic ulcers, pressure sores and ulcers of diabetic feet represents a serious problem, especially in the case of resistant and multi-resistant pathogens. Antibacterial photodynamic therapy can be a promising method of local infected foci treatment of such diseases.This work is devoted to the study of the possibility of photodynamic inactivation (PDI) of Pseudomonas aeruginosa bacteria in the form of biofilms with the help of new polycationic photosensitizers (PSs) based on octacationic phthalocyanine and tetra-and octabacteriochlorins (ZnPcChol 8 , (3-PyBrE) 4 BCBr 4 and (3-PyEPy) 4 BCBr 8 ). More specifically, this work aims to clarify the role of light irradiation in PDI with the participation of new PSs, which has not been fully studied, especially with respect to the comparison of different PS types.

Photodynamic Action in Thin Sensitized Layers: Estimating the Utilization of Light Energy

“…Many PDA problems require the PS excitation in thin (≤ 5 mm) layers of sensitized aqueous compositions. Such problems include photodynamic inactivation of pathogens -viruses or bacteria, on various surfaces [8,9], in vitro screening studies of PS properties [10,11]. For small layer thicknesses and low (less than 10 μM) PS concentrations used for such a PDA, a significant part of the light in the spectral range of the PS absorption band can pass through the layer without participating in the PDA process.…”

Photodynamic Inactivation of Opportunistic Premise Plumbing Pathogens and Their Biofilms

“…Finally, a PS with 8 positive charges, octacationic phthalocyanine (ZnPcChol 8 ), and two bacteriochlorins with 4 and 8 positive charges, tetracationic ((3-PyBrE) 4 BCBr 4 ) and octacationic ((3-PyEPy) 4 BCBr 8 ), were all applied on P. aeruginosa in concentration of 250 µM, and tetracationic bacteriochlorin showed the strongest PDI effect (5-log CFU reduction on biofilm) with the smallest dose of light applied (20 J/cm 2 ) [139]. On the other hand, a complete eradication of the biofilms was achieved with phthalocyanine, although a high dose of light was required (100 J/cm 2 ), so the authors concluded that its high photostability contributed to the success of this PS, given that bacteriochlorins, in particular (3-PyBrE) 4 BCBr 4 , showed rapid and significant photodegradation with increased doses of light [139].…”

Photodynamic action of photosensitizers based on polycationic derivatives of synthetic bacteriochlorin against human lung cancer cells A549

“…They have a shortened length of alkylene chains (from 4 to 2 methylene links). These bacteriochlorins easily penetrate the cell wall, providing high photodynamic inactivation of Gram-positive and Gramnegative bacteria, including in the form of biofilms [4]. At the same time, they do not have a pronounced tendency to aggregate in a wide range of concentrations (up to 100 µM).…”