Photodynamic inactivation of bacteria: Why it is not enough to excite a photosensitizer

Meerovich, Gennady A.; Akhlyustina, Ekaterina V.; Romanishkin, Igor D.; Makarova, Elena A.; Tiganova, Irina G.; Zhukhovitsky, Vladimir G.; Kholina, Ekaterina G.; Kovalenko, Ilya B.; Romanova, Yulia M.; Loschenov, Victor B.; Strakhovskaya, Marina G.

doi:10.1016/j.pdpdt.2023.103853

Cited by 7 publications

(6 citation statements)

References 106 publications

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“…These vesicles are capable of binding biocide molecules at a distance from the parent cell, protecting them from damage. Previously, we created models of flat bilayer membranes containing LPSs of P. aeruginosa either with negatively charged O5 O-antigens or with neutral polyrhamnose antigens [60]. Using these models, we showed that the photosensitizer octakis(cholinyl)zinc phthalocyanine, when interacting with a membrane containing negatively charged antigens, electrostatically binds to antigenic chains and does not reach the core region of LPS molecules.…”

Section: Discussionmentioning

confidence: 99%

“…Given that in our previous study [60], small molecules such as methylene blue reached the core region of LPSs, it was interesting to study the contribution of the core region and lipid A in forming a barrier to the penetration of cationic biocides. To this end, we compared the translocation of the photosensitizer octakis(cholinyl) zinc phthalocyanine, the antiseptic octenidine, and the dye methylene blue into the model OMV.…”

Section: Discussionmentioning

confidence: 99%

“…The value of the harmonic spring of the force constant was 10.000 kJ mol -1 nm -2 . Coarsegrained molecular dynamics models of octakis(cholinyl)zinc phthalocyanine, octenidine, and methylene blue have been created earlier [58][59][60]. Details of the molecular dynamics systems are presented in Table 1.…”

Section: Methodsmentioning

confidence: 99%

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Cationic Biocides Tend to Embed into the Inner Layer of the Model Outer Membrane Vesicles of Gram-negative Bacteria: Computational Insights

Kholina,

Kovalenko,

Strakhovskaya

2024

Math.Biol.Bioinf.

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The outer membrane vesicles (OMVs), produced by many pathogenic bacteria, play a significant role in bacterial pathogenesis. They promote bacterial resistance to antibiotics and act as natural protective barriers. The study of OMVs is essential both for understanding the general mechanisms of bacterial pathogenicity and for the development of the antibacterial drugs. In this paper, we created model vesicle that imitate the OMVs of Gram-negative bacteria using molecular modeling techniques. To investigate the interaction of the cationic antimicrobial compounds with the outer lipopolysaccharide (LPS) monolayer and the inner phospholipid monolayer of the OMV membrane, we performed molecular dynamics simulations by placing molecules of the cationic antiseptic octenidine on the outside or inside of model vesicles. The interaction of octenidine with the outer and inner monolayer was significantly different: octenidine interacted weakly with the outer LPS surface of the model OMV, but exhibited high affinity for the phospholipids of the inner monolayer. To study the translocation of cationic antimicrobial molecules within model OMV, we performed steered molecular dynamics simulations. For all three cationic biocide molecules, antiseptic octenidine, photosensitizer octakis(cholinyl)zinc phthalocyanine, and dye methylene blue, it turned out that, along with the LPS of the outer membrane of the OMV, the phosphates of lipid A molecules represent the final barrier to their penetration into the model OMV.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Cationic Biocides Tend to Embed into the Inner Layer of the Model Outer Membrane Vesicles of Gram-negative Bacteria: Computational Insights

Kholina,

Kovalenko,

Strakhovskaya

2024

Math.Biol.Bioinf.

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“…The synthesis details of the used PS are described in [10]. This PS is known to efficiently bind to these bacteria and inactivate them [8].…”

Section: Methodsmentioning

confidence: 99%

“…The Coulombic electrostatic repulsion between PS molecules with the same charge prevents their aggregation in aqueous solutions, resulting in sustained high quantum yields of ROS of polycationic PSs based on phthalocyanines across a broad range of concentrations [7]. Polycationic photosensitizers effectively bind to Gram-negative bacteria, which are in general more resistant to photodynamic effects, and effectively inactivate them [8]. At the same time, fluorescence correlation spectroscopy findings [7] indicate that due to the high local concentration of polycationic PS molecules near Gram-negative bacteria, local aggregation of PS molecules can occur there.…”

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confidence: 99%

Оn the aggregation of polycationic photosensitizer upon binding to Gram-negative bacteria

Romanishkin,

Akhlyustina,

Meerovich

et al. 2024

Methods Appl. Fluoresc.

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Polycationic photosensitizers (PS) are not susceptible to aggregation in solutions, but their high local concentrations in Gram-negative bacteria can be sufficient for aggregation and reduced effectiveness of antibacterial photodynamic treatment. By measuring fluorescence spectra and kinetics we were able to evaluate the degree of aggregation of polycationic PS ZnPcChol8 in Gram‑negative bacteria E. coli K12 TG1. Binding of ZnPcChol8 to E. coli K12 TG1 leads to an appearance of groups of molecules with shorter PS fluorescence lifetime, a decrease in fluorescence intensity and a shift in the fluorescence spectral maximum. However, we evaluated that about 88% of the fluorescing PS molecules in the bacteria were in an unaggregated state, which indicates only a small reduction in the generation of reactive oxygen species.

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Potential of photodynamic therapy using polycationic photosensitizers in the treatment of lung cancer patients with SARS-CoV-2 infection and bacterial complications: Our recent experience

Meerovich,

Kogan,

Romanishkin

et al. 2025

Photodiagnosis and Photodynamic Therapy

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Photodynamic inactivation of bacteria: Why it is not enough to excite a photosensitizer

Cited by 7 publications

References 106 publications

Cationic Biocides Tend to Embed into the Inner Layer of the Model Outer Membrane Vesicles of Gram-negative Bacteria: Computational Insights

Cationic Biocides Tend to Embed into the Inner Layer of the Model Outer Membrane Vesicles of Gram-negative Bacteria: Computational Insights

Оn the aggregation of polycationic photosensitizer upon binding to Gram-negative bacteria

Potential of photodynamic therapy using polycationic photosensitizers in the treatment of lung cancer patients with SARS-CoV-2 infection and bacterial complications: Our recent experience

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