Antimicrobial Resistance: Is There a ‘Light’ at the End of the Tunnel?

Leanse, Leon G.; Marasini, Sanjay; dos Anjos, Carolina; Dai, Tianhong

doi:10.3390/antibiotics12091437

Cited by 5 publications

(1 citation statement)

References 146 publications

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“…aureus (MRSA), which is challenging to eliminate. aPDT is an alternate mode of treatment for bacterial infections. − aPDT offers several advantages over traditional antimicrobial therapies, including broad-spectrum antimicrobial activity, reduced resistance formation, and effectiveness against biofilms and drug-resistant bacteria. , Blue light (400–450 nm) activated photosensitizers are more effective against cutaneous bacterial infections than other wavelength regions of the visible spectrum. − There is less tissue penetration compared to longer wavelength light, and this prevents deeper tissue damage. , …”

Section: Introductionmentioning

confidence: 99%

Blue-Light-Activated Water-Soluble Sn(IV)-Porphyrins for Antibacterial Photodynamic Therapy (aPDT) against Drug-Resistant Bacterial Pathogens

Nagarajan,

Gayathri,

Mack

et al. 2024

Mol. Pharmaceutics

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Antimicrobial resistance has emerged as a global threat to the treatment of infectious diseases. Antibacterial photodynamic therapy (aPDT) is a promising alternative approach and is highly suitable for the treatment of cutaneous bacterial infections through topical applications. aPDT relies on lightresponsive compounds called photosensitizer (PS) dyes, which generate reactive oxygen species (ROS) when induced by light, thereby killing bacterial cells. Despite several previous studies in this area, the molecular details of targeting and cell death mediated by PS dyes are poorly understood. In this study, we further investigate the antibacterial properties of two water-soluble Sn(IV) tetrapyridylporphyrins that were quaternized with methyl and hexyl groups (1 and 2). In this follow-up study, we demonstrate that Sn(IV)-porphyrins can be photoexcited by blue light (a 427 nm LED) and exhibit various levels of bactericidal activity against both Gram-(+) and Gram-(−) strains of bacteria. Using localization studies through fluorescence microscopy, we show that 2 targets the bacterial membrane more effectively than 1 and exhibits comparatively higher aPDT activity. Using multiple fluorescence reporters, we demonstrate that photoactivation of 1 and 2 results in extensive collateral damage to the bacterial cells including DNA cleavage, membrane damage, and delocalization of central systems necessary for bacterial growth and division. In summary, this investigation provides deep insights into the mechanism of bacterial killing mediated by the Sn(IV)-porphyrins. Moreover, our approach offers a new method for evaluating the activity of PS, which may inspire the discovery of new PS with enhanced aPDT activity.

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Section: Introductionmentioning

confidence: 99%

Blue-Light-Activated Water-Soluble Sn(IV)-Porphyrins for Antibacterial Photodynamic Therapy (aPDT) against Drug-Resistant Bacterial Pathogens

Nagarajan,

Gayathri,

Mack

et al. 2024

Mol. Pharmaceutics

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Design and Nanoengineering of Photoactive Antimicrobials for Bioapplications: from Fundamentals to Advanced Strategies

Xin,

Liu,

Xiao

et al. 2024

Adv Funct Materials

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Currently, microbial infections have posed an arduous challenge to global public health, whereas the rise of antibiotic resistance is rendering traditional antibiotic therapies futile, prompting the development of new antimicrobial technologies. Photoactive nanomaterials have thus garnered a thriving interest for disinfection owing to their superior antibacterial efficaciousness, favorable biosafety, and rapidness and spatiotemporal precision in excreting bactericidal actions. The review summarizes recent advances and emerging trends in the design, nanoengineering, and bioapplications of photoactive antimicrobials. It commences by elaborating fundamental theories on bacterial resistance, and antibacterial mechanisms of nanomaterials and phototherapy. Subsequently, the regulation of the antibacterial effectiveness of photoactive nanomaterials is comprehensively discussed, centering on criteria and strategies for tuning photoabsorption spectra, photothermal conversion, and photocatalytic efficiency, alongside tactics for enabling synergistic therapies. This is followed by comparative analyses of techniques and modalities for synthesizing and engineering photoactive nanomaterials with diverse structures, forms, and functionalities. Thereafter, the state‐of‐the‐art applications of phototherapies across various medical sectors are portrayed, and key challenges and opportunities are finally discussed to spur future innovations and translation. This review is envisaged to provide useful guidance for devising and developing nanomaterials‐based photoresponsive antimicrobials with application‐specific materials properties and biological functions.

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Potential of using medicinal plant extracts as photosensitizers for antimicrobial photodynamic therapy

Mikulich,

Plavskii,

Tretyakova

et al. 2024

Photochem & Photobiology

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Antimicrobial photodynamic therapy (APDT) is a promising approach to overcome antimicrobial resistance. However, for widespread implementation of this approach, approved photosensitizers are needed. In this study, we used commercially available preparations (Calendulae officinalis floridis extract, Chamomillae recutitae floridis extract, Achillea millefolii herbae extract; Hypericum perforatum extract; Eucalyptus viminalis folia extract) as photosensitizers for inactivation of gram‐negative (Pseudomonas aeruginosa) and gram‐positive (Staphylococcus aureus) bacteria. Spectral‐luminescent analysis has shown that the major chromophores are of chlorophyll (mainly chlorophyll a and b) and hypericin nature. The extracts are efficient generators of singlet oxygen with quantum yield (γΔ) from 0.40 to 0.64 (reference compound, methylene blue with γΔ = 0.52). In APDT assays, bacteria before irradiation were incubated with extracts for 30 min. After irradiation and 24 h of incubation, colony‐forming units (CFU) were counted. Upon exposure of P. aeruginosa to radiation of 405 nm, 590 nm, and 660 nm at equal energy dose of 30 J/cm2 (irradiance – 100 mW/cm2, exposure time – 5 min), the most pronounced effect is observed with blue light (>3 log10 reduction); in case of S. aureus, the effect is approximately equivalent for light of indicated wavelengths and dose (>4 log10 reduction).

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Antimicrobial Resistance: Is There a ‘Light’ at the End of the Tunnel?

Cited by 5 publications

References 146 publications

Blue-Light-Activated Water-Soluble Sn(IV)-Porphyrins for Antibacterial Photodynamic Therapy (aPDT) against Drug-Resistant Bacterial Pathogens

Blue-Light-Activated Water-Soluble Sn(IV)-Porphyrins for Antibacterial Photodynamic Therapy (aPDT) against Drug-Resistant Bacterial Pathogens

Design and Nanoengineering of Photoactive Antimicrobials for Bioapplications: from Fundamentals to Advanced Strategies

Potential of using medicinal plant extracts as photosensitizers for antimicrobial photodynamic therapy

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