Light sources for photodynamic inactivation of bacteria

Călin, Mihaela Antonina; Parasca, Sorin Viorel

doi:10.1007/s10103-008-0588-5

Cited by 71 publications

(51 citation statements)

References 26 publications

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“…Different light sources with diverse characteristics are used both in research and in clinical applications. 25,26 By altering the illumination period, different irradiance values can be used to deposit one specific light dose. However, the tumor response may not solely depend on the light dose but may also depend on the irradiance.…”

Section: Discussionmentioning

confidence: 99%

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Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcomein vitro

et al. 2014

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Abstract. Hexyl 5-aminolevulinate (HAL) is a lipophilic derivative of 5-aminolevulinate, a key intermediate in biosynthesis of the photosensitizer protoporphyrin IX (PpIX). The photodynamic efficacy and cell death mode after red versus blue light illumination of HAL-induced PpIX have been examined and compared using five different cancer cell lines. LED arrays emitting at 410 and 624 nm served as homogenous and adjustable light sources. Our results show that the response after HAL-PDT is cell line specific, both regarding the shape of the dose-survival curve, the overall dose required for efficient cell killing, and the relative amount of apoptosis. The ratio between 410 and 624 nm in absorption coefficient correlates well with the difference in cell killing at the same wavelengths. In general, the PDT efficacy was several folds higher for blue light as compared with red light, as expected. However, HAL-PDT 624 induced more apoptosis than HAL-PDT 410 and illumination with low irradiance resulted in more apoptosis than high irradiance at the same lethal dose. This indicates differences in death modes after low and high irradiance after similar total light doses. From a treatment perspective, these differences may be important. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Discussionmentioning

confidence: 99%

“…2 and 3 in Table 1. We have tabulated the values resulting in 25%, 50%, 75%, and 90% cell death, for LD 25 , LD 50 , LD 75 , and LD 90 , respectively. Since the slope of the dose-response curves is very flat when approaching 100% cell death, the definition of LD 100 is somewhat subjective, and we chose to use the term "LD ∼100 " instead.…”

Section: (7 Mw∕cmmentioning

confidence: 99%

Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcomein vitro

et al. 2014

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“…Free radicals are formed, such as oxygen species that have a toxic effect on cells. [11][12][13][14] PDT is a repeatable procedure which costs less than other methods, has a broad spectrum microbicidal effects, is safe for the host tissue, and can reach inaccessible sites. 15 Another alternative method to treat periodontal diseases is to find substances with anti-plaque effects that can inhibit bacterial reproduction.…”

Section: Introductionmentioning

confidence: 99%

An In Vitro Comparison of Antimicrobial Effects of Curcumin-Based Photodynamic Therapy and Chlorhexidine, on Aggregatibacter actinomycetemcomitans

et al. 2016

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IntroductionPeriodontal diseases are referred to as inflammatory processes in periodontal tissues in response to the aggregation of bacteria on the teeth. The aggregation rarely leads to evident infection, but the inflammatory response caused in the gingival tissue is responsible for the gradual loss of dental collagen's attachment to the alveolar bone. Left overlooked, this phenomenon might end in increased dental mobility and eventually edentulism.1 Production of destructive metabolites by gram negative and positive bacteria of the microbial plaque in the oral cavity causes gingivitis, which can play a key role in the progression of inflammation to periodontal diseases. 2Aggregatibacter actinomycetemcomitans is an immobile microaerophilic, facultative anaerobic, gram negative coccoid rod, 3 strongly associated with pathogenesis of periodontal diseases, particularly aggressive generalized periodontitis.4 Some of this bacterium's membranous proteins play an important role in attachment to and penetration in tissue cells.5 Other virulence factors secreted by this bacterium include an agent that inhibits the reproduction of fibroblasts and a leukotoxin that kills the leukocytes. 6 Despite the many complications caused by periodontitis, no treatment protocol is known to be able to fully control this disease. Currently, a combination of mechanical treatments and systemic antibiotics are used as treatment 7 ; however, periodontal pathogens are not completely removed by the mechanical removal of the biofilm; and there are problems associated with the use of antibiotics, Abstract Introduction: Considering the importance of prevention in periodontal diseases and the important role of Aggregatibacter actinomycetemcomitans in induction and progression of these diseases, the aim of the present in vitro study was to compare the antimicrobial effects of chlorhexidine digluconate (CHX), curcumin and light-emitting diode (LED) laser, on this bacterium. Methods: Antimicrobial activity of curcumin (5 mg/ml), CHX (2%), LED (120 J/cm 2 ) and LED + curcumin (120 J/cm 2 + 2.5 mg/ml) against A. actinomycetemcomitans were tested in vitro, using micro-broth dilution test. One-way analysis of variance (ANOVA) and Tukey's HSD tests served for statistical analysis. Results: Regarding the minimum inhibitory concentration (MIC), CHX had a significantly lower MIC than curcumin (P < 0.05). Sorted out by bacterial growth from lowest to highest, were CHX, LED + curcumin, curcumin, and LED groups. All the differences were found to be statistically significant (P < 0.05) except for the LED group. Conclusion: We conclude that curcumin is an effective substance in preventing the growth of A. actinomycetemcomitans, whose impact is reinforced when used simultaneously with photodynamic therapy (PDT).

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“…Their mechanism of action is characterized by the production of highly reactive oxygen species ( 1 O 2 ) responsible for the oxidation of a biologic target after activation by suitable light doses [12]. Porphyrins and their derivatives have shown high effectiveness against a broad spectrum of insect vectors.…”

Section: Introductionmentioning

confidence: 99%

Efficacy of Photogem® (Hematoporphyrin Derivative) as a Photoactivatable Larvicide against Aedes aegypti (Diptera: Culicidae) Larvae

Souza¹,

Inada²,

Pratavieira³

et al. 2017

JLS

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Dengue vector is responsible for millions of deaths every year and has caused disastrous impacts on health systems. The continuous use of chemical insecticides, such as carbamates, pyrethroids and organophosphates generates resistant populations of the mosquito, therefore, new control methods must be investigated. The joint action of the population and guidelines for preventing the reproduction of the mosquito associated with the use of photoactivatable insecticides can be the alternative for the control of epidemiological outbreaks in affected regions. In this study, the photo-larvicidal activity of Photogem ® (PG), a derivative of hematoporphyrin, was investigated against 2 nd -early 3 rd instar of Aedes aegypti larvae (Diptera: Culicidae) under different lighting conditions (artificial lighting system and sunlight). The dynamics of PG accumulation was characterized by CLSM (confocal laser scanning microscopy) and total time PG eliminationin solution was investigated by ultraviolet-visible spectrophotometry. The maximum photo-activity of PG was observed in 0.5 h under sunlight exposure which achieved 100% larval mortality. Fluorescence images showed a uniform distribution of PG along the digestive tract. PG remained stable in the sunlight for 48 h and in an artificial lighting system for longer periods, therefore, it can be used for the control of Aedes aegypti larvae as a new alternative to chemical insecticides. The method is considered environmentally friendly due to its rapid degradation in the presence of light. Further studies are required, so that the potential of the technique can be explored in real breeding places.

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Light sources for photodynamic inactivation of bacteria

Cited by 71 publications

References 26 publications

Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcomein vitro

Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcomein vitro

An In Vitro Comparison of Antimicrobial Effects of Curcumin-Based Photodynamic Therapy and Chlorhexidine, on Aggregatibacter actinomycetemcomitans

Efficacy of Photogem® (Hematoporphyrin Derivative) as a Photoactivatable Larvicide against Aedes aegypti (Diptera: Culicidae) Larvae

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