Photodynamic Therapy in Planktonic and Biofilm Cultures of <i>Aggregatibacter actinomycetemcomitans</i>

Goulart, Rosangela de Carvalho; Bolean, Maytê; Paulino, Tony de Paiva; Thedei, Geraldo; Souza, Sérgio Luı́s Scombatti de; Tedesco, Antônio Cláudio; Ciancaglini, Pietro

doi:10.1089/pho.2009.2591

Cited by 74 publications

(49 citation statements)

References 32 publications

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“…1A). This is in agreement with previously published reports using blue light (400-500 nm) to photoactivate RB [10,12]. Also, light irradiation alone (240 s) had no effect on E. faecalis but reduced F. nucleatum viability by approximately 10%.…”

Section: Discussionsupporting

confidence: 93%

“…The use of blue light-mediated aPDT has stemmed from the widespread availability of dental blue-light sources having a broad emission spectrum (400-500 nm) and a high energy per photon [11]. Blue light-activated rose bengal was shown to inactivate S. mutans, A. actinomycetemcomitans and C. albicans in several research reports that also confirmed the influence of the amount of light energy delivered on bacterial killing [10,12,13].…”

Section: Introductionmentioning

confidence: 96%

“…The combinational use of rose bengal and blue-light has recently gained interest to inactivate several oral pathogens causing dental and periodontal diseases [8,9,10]. The use of blue light-mediated aPDT has stemmed from the widespread availability of dental blue-light sources having a broad emission spectrum (400-500 nm) and a high energy per photon [11].…”

Section: Introductionmentioning

confidence: 99%

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Rose bengal uptake by E. faecalis and F. nucleatum and light-mediated antibacterial activity measured by flow cytometry

Manoil

Filieri

Schrenzel

et al. 2016

Journal of Photochemistry and Photobiology B: Biology

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Rose bengal uptake by E. faecalis and F. nucleatum and light-mediated antibacterial activity measured by flow cytometry Antibacterial photodynamic therapy (aPDT) using rose bengal (RB) and blue-light kills bacteria through the production of reactive oxygen derivates. However, the interaction mechanism of RB with bacterial cells remains unclear. This study investigated the uptake efficiency and the antibacterial activity of blue light-activated RB against Enterococcus faecalis and Fusobacterium nucleatum. Spectrophotometry and epifluorescence microscopy were used to evaluate binding of RB to bacteria. The antibacterial activity of RB after various irradiation times was assessed by flow cytometry in combination with cell sorting. Uptake of RB increased in a concentration dependent manner in both strains although E. faecalis displayed higher uptake values. RB appeared to bind specific sites located at the cellular poles of E. faecalis and at regular intervals along F. nucleatum. Blue-light irradiation of samples incubated with RB significantly reduced bacterial viability. After incubation with 10 μM RB and 240 s irradiation, only 0.01% (± 0.01%) of E. faecalis cells and 0.03% (±0.03%) of F. nucleatum survived after treatment. This study indicated that RB can bind to E. faecalis and F. nucleatum in a sufficient amount to elicit effective aPDT. Epifluorescence microscopy showed a yet-unreported property of RB binding to bacterial membranes. Flow cytometry allowed the detection of bacteria with damaged membranes that were unable to form colonies on agars after cell sorting.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Rose bengal uptake by E. faecalis and F. nucleatum and light-mediated antibacterial activity measured by flow cytometry

Manoil

Filieri

Schrenzel

et al. 2016

Journal of Photochemistry and Photobiology B: Biology

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“…However, for both the continuous and intermittent groups, increasing concentrations of eosin Y did not improve antibacterial activity as observed for the 40-80 M concentrations. As reported by Goulard et al, when high concentrations of photosensitizers are incubated for longer periods of time, they can form aggregates, thereby decreasing treatment efficiency [32]. Also, a longer irradiation time may have accelerated photobleaching of the photosensitizer, which was shown to occur with irradiation times longer than 15 min [33].…”

Section: Discussionmentioning

confidence: 89%

“…The antibacterial properties of Photosan light-activated with a commercially available dental photopolymerizer emitting blue light were reported against the Gram-positive S. mutans and Enterococcus faecalis in planktonic cultures [6]. Other research indicates that Aggregatibacter actinomycetemcomitans, a Gram-negative pathogen causing periodontal disease, can be inactivated by rose bengal exposed to bluelight irradiation, both in planktonic and biofilm cultures [7]. Papastamou et al assessed various formulations of ruthenium exposed to blue light for inactivating Fusobacterium nucleatum and Porphyromonas gingivalis and reported a significant reduction in viability of both pathogens after treatment [8].…”

Section: Introductionmentioning

confidence: 99%

Repeated exposures to blue light-activated eosin Y enhance inactivation of E. faecalis biofilms, in vitro

Marinic

Manoil

Filieri

et al. 2015

Photodiagnosis and Photodynamic Therapy

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Background: In dentistry, antibacterial photodynamic therapy (a-PDT) has shown promising results for inactivating bacterial biofilms causing carious, endodontic and periodontal diseases. In the current study, we assessed the ability of eosin Y exposed to 3 irradiation protocols at inactivating Enterococcus faecalis biofilms, in vitro. Methods: E. faecalis biofilms formed on hydroxyapatite disks were incubated with eosin Y (10-80 M), then activated with blue light using different irradiation protocols. Biofilms exposed to continuous exposure were incubated for 40 min before being light-activated for 960 s. For the intermittent exposure, biofilms were exposed 4 times to the light/photosensitizer combination (960 s total) without renewing the photosensitizer. For repeated a-PDT, the same light dose was delivered in a series of 4 irradiation periods separated by dark periods; fresh photosensitizer was added between each light irradiation. After treatment, bacteria were immediately labeled with LIVE/DEAD BacLight Bacterial Viability kit and viability was assessed by flow cytometry (FCM). Results were statistically analyzed using one-way ANOVA and Tukey multiple comparison intervals (˛= 0.05). * Corresponding author. Results:The viability of E. faecalis biofilms exposed to 10 M eosin Y, was significantly reduced compared to controls (light only-eosin Y only). After a second exposure to blue light-activated eosin Y, viability significantly decreased from 58% to 12% whereas 6.5% of the bacterial biofilm remained live after a third exposure (p < 0.05). Only 3.5% of the bacterial population survived after the fourth exposure. Conclusions:The results of this study indicate that blue light-activated eosin Y can photoinactivate E. faecalis biofilms grown on hydroxyapatite disks. Also, repeated exposures to blue light-activated eosin Y were shown to significantly improve efficacy. Further studies seem warranted to optimize the antibacterial activity of blue light-activated eosin Y on major oral pathogens.

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Intracanal Medication in Root Canal Disinfection

Silva

Nelson‐Filho

Cohenca

2014

Disinfection of Root Canal Systems

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Photodynamic Therapy in Planktonic and Biofilm Cultures of Aggregatibacter actinomycetemcomitans

Abstract: Photodynamic therapy-generated ROS inactivates A. actinomycetemcomitans both in planktonic and biofilm cultures, even in small concentrations of the photosensitizing agent, and it does not cause damage to fibroblast cells under the same conditions.

Cited by 74 publications

References 32 publications

Rose bengal uptake by E. faecalis and F. nucleatum and light-mediated antibacterial activity measured by flow cytometry

Rose bengal uptake by E. faecalis and F. nucleatum and light-mediated antibacterial activity measured by flow cytometry

Repeated exposures to blue light-activated eosin Y enhance inactivation of E. faecalis biofilms, in vitro

Intracanal Medication in Root Canal Disinfection

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