Inhibitory effects of calcium or magnesium ions on PDI

Eckl, Daniel Bernhard; Landgraf, Nicole; Hoffmann, Anja Karen; Schottenhaml, Laura; Dirscherl, Julia; Weber, Nina; Eben, Stefanie Susanne; Bäßler, Pauline; Eichner, Anja; Huber, Harald; Bäumler, Wolfgang

doi:10.1016/j.jpap.2022.100122

Cited by 4 publications

(6 citation statements)

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“…Findings from this study did not find any differences in PS uptake in the presence of calcium or magnesium. This hints at the fact that divalent ions also a shielding effect due to electrostatic effects forcing the PS to bind to distant cell structures not vital for the survival of the bacteria (83). It might therefore be speculated that chelating agents not only destabilize the membrane but also reduce the potential shielding effect of divalent ions in PDI.…”

Section: Discussionmentioning

confidence: 99%

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate^†

Eckl

Landgraf

Hoffmann

et al. 2022

Photochem & Photobiology

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Many studies show that photodynamic inactivation (PDI) is a powerful tool for the fight against pathogenic, multiresistant bacteria and the closing of hygiene gaps. However, PDI studies have been frequently performed under standardized in vitro conditions comprising artificial laboratory settings. Under real-life conditions, however, PDI encounters substances like ions, proteins, amino acids and fatty acids, potentially hampering the efficacy of PDI to an unpredictable extent. Thus, we investigated PDI with the phenalene-1-onebased photosensitizer SAPYR against Escherichia coli and Staphylococcus aureus in the presence of calcium or magnesium ions, which are ubiquitous in potential fields of PDI applications like in tap water or on tissue surfaces. The addition of citrate should elucidate the potential as a chelator. The results indicate that PDI is clearly affected by such ubiquitous ions depending on its concentration and the type of bacteria. The application of citrate enhanced PDI, especially for Gram-negative bacteria at certain ionic concentrations (e.g. CaCl 2 or MgCl 2 : 7.5 to 75 mmol L −1 ). Citrate also improved PDI efficacy in tap water (especially for Gramnegative bacteria) and synthetic sweat solution (especially for Gram-positive bacteria). In conclusion, the use of chelating agents like citrate may facilitate the application of PDI under real-life conditions.

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Section: Discussionmentioning

confidence: 99%

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate^†

Eckl

Landgraf

Hoffmann

et al. 2022

Photochem & Photobiology

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“…44 Also, divalent ions like magnesium and calcium in sweat already proved to disturb PDI. They bind to bacterial cells and thereby interfere with the attachment of photosensitizers to the bacterial membranes, 34 but this can be overcome by using a chelator citrate. 45 In summary, the next experiments particularly focused on the influence of such sweat ions and histidine as exemplary amino acid.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, there are still problems when performing PDI on skin due to the presence of some substances on the skin surface like divalent ions 32–34 . Moreover, the application of a photosensitizer dissolved in pure water is not only impractical but also hampers the important wetting of the bacteria with the photosensitizer solution.…”

Section: Introductionmentioning

confidence: 99%

“…17 Nevertheless, there are still problems when performing PDI on skin due to the presence of some substances on the skin surface like divalent ions. [32][33][34] Moreover, the application of a photosensitizer dissolved in pure water is not only impractical but also hampers the important wetting of the bacteria with the photosensitizer solution. Such wetting is important for the maximum proximity of photosensitizers and bacteria, which ensures good accessibility of the bacteria by singlet oxygen.…”

Section: Introductionmentioning

confidence: 99%

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Photodynamic inactivation of different pathogenic bacteria on human skin using a novel photosensitizer hydrogel

Eckl

Hoffmann

Landgraf

et al. 2023

Acad Dermatol Venereol

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Background The colonization of skin with pathogenic, partially antibiotic‐resistant bacteria is frequently a severe problem in dermatological therapies. For instance, skin colonization with Staphylococcus aureus is even a disease‐promoting factor in atopic dermatitis. The photodynamic inactivation (PDI) of bacteria could be a new antibacterial procedure. Upon irradiation with visible light, a special photosensitizer exclusively generates singlet oxygen. This reactive oxygen species kills bacteria via oxidation independent of species or strain and their antibiotic resistance profile causing no bacterial resistance on its part. Objective To investigate the antibacterial potential of a photosensitizer, formulated in a new hydrogel, on human skin ex vivo. Methods The photochemical stability of the photosensitizer and its ability to generate singlet oxygen in the hydrogel was studied. Antimicrobial efficacy of this hydrogel was tested step by step, firstly on inanimate surfaces and then on human skin ex vivo against S. aureus and Pseudomonas aeruginosa using standard colony counting. NBTC staining and TUNEL assays were performed on skin biopsies to investigate potential necrosis and apoptosis effects in skin cells possibly caused by PDI. Results None of the hydrogel components affected the photochemical stability and the life time of singlet oxygen. On inanimate surfaces as well as on the human skin, the number of viable bacteria was reduced by up to 4.8 log10 being more effective than most other antibacterial topical agents. Histology and assays showed that PDI against bacteria on the skin surface caused no harmful effects on the underlying skin cells. Conclusion Photodynamic inactivation hydrogel proved to be effective for decolonization of human skin including the potential to act against superficial skin infections. Being a water‐based formulation, the hydrogel should be also suitable for the mucosa. The results of the present ex vivo study form a good basis for conducting clinical studies in vivo.

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“…For example, in PDI with SAPYR (2-((4-pyridinyl)methyl)-1H-phenalen-1one chloride) against Escherichia coli and S. aureus, the impact of calcium or magnesium ions, which are ubiquitous in tap water, was studied toward applications such as water disinfection. Photodynamic action was impaired by these ions because the binding of the PS to the bacterial cell competes with these ions (although differently for different bacteria), although the enhanced PDI was achieved when citrate was used as chelator for these ions [105]. The effect of phosphate and carbonate ions on PDI with two cationic flavin PSs against P. aeruginosa reduced singlet oxygen production and increased the photodegradation of both PSs, although through different by-products and on both events, 1 O 2 production, and photodegradation, carbonate ions had more adverse effects than phosphate ions.…”

Section: Photodynamic Inactivation (Pdi)-mechanism Exogenous Photosen...mentioning

confidence: 99%

Photodynamic Inactivation of Opportunistic Premise Plumbing Pathogens and Their Biofilms

Mušković,

Gobin,

Malatesti

2023

Processes

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Opportunistic premise plumbing pathogens (OPPPs) form a group of microorganisms that normally live in water supply systems and have adapted especially well to the conditions in premise plumbing systems, and as such pose a threat to human health. Since the beginning of the 21st century, this threat has been escalating, and it is becoming increasingly evident that current water disinfection methods fall short in effectively controlling these pathogens. In researching new approaches to this emergency, phototherapy looks promising, especially one that combines photosensitizers, light, and oxygen, which is known as photodynamic inactivation (PDI). This review describes the main characteristics of the recognized (Pseudomonas aeruginosa, Legionella pneumophila, and Mycobacterium avium) and most important emerging OPPPs, and it offers a brief overview of current disinfection methods and their limitations in the fight against OPPPs. The principle and outcomes of PDI with endogenous and, in particular, exogenous photosensitizers are then explained and described through representative examples of PDI on recognized and emerging OPPPs and their biofilms. Finally, the prospects and future directions of PDI research in water disinfection and control of OPPPs are discussed.

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Inhibitory effects of calcium or magnesium ions on PDI

Cited by 4 publications

References 84 publications

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate^†

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate^†

Photodynamic inactivation of different pathogenic bacteria on human skin using a novel photosensitizer hydrogel

Photodynamic Inactivation of Opportunistic Premise Plumbing Pathogens and Their Biofilms

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Inhibitory effects of calcium or magnesium ions on PDI

Cited by 4 publications

References 84 publications

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate†

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate†

Photodynamic inactivation of different pathogenic bacteria on human skin using a novel photosensitizer hydrogel

Photodynamic Inactivation of Opportunistic Premise Plumbing Pathogens and Their Biofilms

Contact Info

Product

Resources

About

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate^†

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate^†