The role of singlet oxygen and oxygen concentration in photodynamic inactivation of bacteria

Maisch, Tim; Baier, Johannes; Franz, Bárbara; Maier, Max; Landthaler, Míchael; Szeimies, Rolf‐Markus; Bäumler, Wolfgang

doi:10.1073/pnas.0611328104

Cited by 367 publications

(298 citation statements)

References 48 publications

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“…[12][13][14] The free radicals produced during cross-linking interfere with the microbial cell wall. 15,16 However, it has not yet been fully decided which of the 2 effects, increased resistance against enzymatic digestion or antimicrobial power, is the predominant force in stabilizing the infectious process in the cornea. On the other hand, in 3 of the 5 eyes, there was a remarkable immediate response to the CXL, which led us to believe that the microbes are destroyed during CXL.…”

Section: Discussionmentioning

confidence: 99%

Ultraviolet A/Riboflavin Corneal Cross-linking for Infectious Keratitis Associated With Corneal Melts

Iseli¹,

Thiel²,

Hafezi³

et al. 2008

Cornea

283

203

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Purpose: To evaluate the efficacy of ultraviolet-corneal crosslinking (CXL) for treating infectious melting keratitis.Methods: Five patients with infectious keratitis associated with corneal melting were treated with CXL at the outpatient departments of the Institut für Refraktive und Ophthalmo-Chirurgie and the eye hospital at the University of Zurich. CXL was performed when the infection did not respond to systemic and topical antibiotic therapy. Follow-up after cross-linking ranged from 1 to 9 months.Results: In all cases, the progression of corneal melting was halted after CXL treatment. Emergency keratoplasty was not necessary in any of the 5 cases presented.Conclusions: CXL is a promising option for treating patients with therapy-refractory infectious keratitis to avoid emergency keratoplasty.

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Section: Discussionmentioning

confidence: 99%

Ultraviolet A/Riboflavin Corneal Cross-linking for Infectious Keratitis Associated With Corneal Melts

Iseli¹,

Thiel²,

Hafezi³

et al. 2008

Cornea

283

203

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“…A significant reduction of the total bacterial load was described previously with this combination for the treatment of chronic wounds (von Felbert et al, 2008). Such effects are potentially of great importance in dental medicine, since VIS+wIRA is indicated for chronic pain relief and is capable of increasing the tissue oxygen partial pressure and stimulating metabolism (Hartel et al, 2006;von Felbert et al, 2010;Maisch et al, 2007). Additionally, due to its penetration properties, wIRA causes energy transfers into subcutaneous tissue without overheating the skin (Fuchs et al, 2004).…”

Section: Introductionmentioning

confidence: 88%

“…Such effects are potentially of great importance in dental Abbreviations: APDT, antimicrobial photodynamic therapy; BES, bovine enamel slabs; PDT, photodynamic therapy; TB, toluidine blue; VIS, visible light; wIRA, water-filtered infrared-A. medicine, since VIS+wIRA is indicated for chronic pain relief and is capable of increasing the tissue oxygen partial pressure and stimulating metabolism (Hartel et al, 2006;von Felbert et al, 2010;Maisch et al, 2007). Additionally, due to its penetration properties, wIRA causes energy transfers into subcutaneous tissue without overheating the skin (Fuchs et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Antimicrobial photodynamic therapy using visible light plus water-filtered infrared-A (wIRA)

Al‐Ahmad

Tennert

Karygianni

et al. 2013

Journal of Medical Microbiology

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The aim of this study was to investigate the effectiveness of antimicrobial photodynamic therapy (APDT) using visible light together with water-filtered infrared-A (VIS+wIRA) to eradicate single species of planktonic bacteria and micro-organisms during initial oral bacterial colonization in situ. A broadband VIS+wIRA radiator with a water-filtered spectrum in the range 580-1400 nm was used for irradiation. Toluidine blue (TB) was utilized as a photosensitizer at concentrations of 5, 10, 25 and 50 mg ml "1 . The unweighted (absolute) irradiance was 200 mW cm "2 and it was applied for 1 min. Planktonic cultures of Streptococcus mutans and Enterococcus faecalis were treated with APDT. Salivary bacteria harvested by centrifugation of native human saliva were also tested. In addition, initial bacterial colonization of bovine enamel slabs carried in the mouths of six healthy volunteers was treated in the same way. Up to 2 log 10 of S. mutans and E. faecalis were killed by APDT. Salivary bacteria were eliminated to a higher extent of 3.7-5 log 10 . All TB concentrations tested proved to be highly effective. The killing rate of bacteria in the initial oral bacterial colonization was significant (P50.004) at all tested TB concentrations, despite the interindividual variations found among study participants. This study has shown that APDT in combination with TB and VIS+wIRA is a promising method for killing bacteria during initial oral colonization. Taking the healing effects of wIRA on human tissue into consideration, this technique could be helpful in the treatment of peri-implantitis and periodontitis. INTRODUCTIONAlthough photodynamic therapy (PDT) is currently being applied in cancer cell elimination (Allison & Sibata, 2010;Ericson et al., 2008), more attention has been paid to its application in antimicrobial treatment (Wood et al., 2006;Donnelly et al., 2007;Maisch, 2007). Due to the growing number of antibiotic-resistant micro-organisms, research is focusing on PDT as an alternative chemotherapy modality (Garcez et al., 2010;Kharkwal et al., 2011). Since PDT causes damage to different parts of microbial cells and affects different interaction pathways in the micro-organisms, the development of antibiotic resistance against PDT can be excluded (Wainwright et al., 2010).PDT impresses with its excellent target-cell specificity and high efficiency. The photodynamic effect requires a photosensitizer, suitable light and oxygen. The photosensitizer can be transferred to the high-energy triplet state and reacts with oxygen, producing singlet oxygen and other radical species which themselves cause increased target cell damage (Konopka & Goslinski, 2007). The photosensitizer should be non-toxic and show antimicrobial activity only after activation by illumination. In addition it should not be bio-destructible. Light sources used in PDT should produce low-power visible light at a specific wavelength (or range of wavelengths) which itself does not harm human tissues in the absence of the photosensitizer. Additionally, light s...

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“…Although SOSG has been commercially available since 2004, there are only two reports on its successful application: one in Staphylococcus bacteria [29] and another in plant leaves including PI studies [30].…”

Section: Sosgmentioning

confidence: 99%

A comparative study of fluorescent singlet oxygen probes in plant leaves

Hideg

2008

Open Life Sciences

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Four fluorescent singlet oxygen sensors: DanePy, its oxalate salt, Singlet Oxygen Sensor Green and MVP, were infiltrated into tobacco leaves and tested for toxicity, subcellular localization, light sensitivity and capacity to trap the singlet oxygen produced in photoinhibition. For reference, a broad sensitivity free radical probe, TEMPO-9-AC, was also included. Photochemical yield was approximately 15% and 10% inhibited by Singlet Oxygen Sensor Green and MVP, respectively, but was not significantly affected by the other probes. Under photoinhibitory conditions, brought about by irradiating lincomycin-treated leaves with strong photosynthetically active radiation, DanePy and Singlet Oxygen Sensor Green were responsive. Singlet Oxygen Sensor Green was also reactive to low, non-photoinhibitory light exposure of the leaf, which was not characteristic to the other probes. MVP did not respond to singlet oxygen which can partly be explained by a possible attenuation of its blue emission in the leaf, as shown by the example TEMPO-9-AC. DanePy-oxalate did not respond to photosynthetic singlet oxygen due to lack of its penetration into photosynthetic tissue and hence could be useful in detecting any singlet oxygen which escapes from a chloroplast initiation site. DanePy was localized in the chloroplasts, while Singlet Oxygen Sensor Green was mainly found in the epidermal cells preferentially associated with the nucleus.

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The role of singlet oxygen and oxygen concentration in photodynamic inactivation of bacteria

Cited by 367 publications

References 48 publications

Ultraviolet A/Riboflavin Corneal Cross-linking for Infectious Keratitis Associated With Corneal Melts

Ultraviolet A/Riboflavin Corneal Cross-linking for Infectious Keratitis Associated With Corneal Melts

Antimicrobial photodynamic therapy using visible light plus water-filtered infrared-A (wIRA)

A comparative study of fluorescent singlet oxygen probes in plant leaves

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