Letícia Heineck Alvarenga1, Renato Araujo Prates2, Tania Mateus Yoshimura3, Ilka Tiemy Kato4, Luis Cláudio Suzuki3, Martha Simões Ribeiro3, Luis Rodolfo Ferreira5, Sílvio Antônio Dos Santos Pereira1, Elizabeth Ferreira Martinez1, Eduardo Saba-Chujfi1. 1. Dental Research Center, São Leopoldo Mandic, Campinas, Brazil. 2. Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil; School of Dentistry, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil. Electronic address: pratesra@uninove.br. 3. Center for Lasers and Applications, Nuclear and Energy Research Institute IPEN-CNEN/SP, São Paulo, Brazil. 4. Department of Biomedical Engineering, ABC Federal University (UFABC), Santo Andre, SP, Brazil. 5. Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil; School of Dentistry, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil.
Abstract
BACKGROUND: The purpose of this study was to evaluate the antibacterial effects of photodynamic action of methylene blue (MB) against Aggregatibacter actinomycetemcomitans organized on biofilm. METHODS: After the biofilm growth in 96 flat-bottom well plate, the following groups were used: control group, untreated by either laser or photosensitizer (PS); MB group or dark toxicity group, which was exposed to MB alone (100μM) for 1min (pre-irradiation time); laser group, irradiated with laser for 5min in the absence of PS and three antimicrobial photodynamic inactivation (APDI) groups, with three exposure times of 1, 3 and 5min of irradiation, corresponding to fluences of 15, 45, and 75J/cm(2) respectively. The results were compared to the control group for statistical proposes. Scanning electronic microscope analysis was used to access structural changes in biofilm. RESULTS: Red laser alone and MB alone were not able to inactivate bacterial biofilm. APDI groups showed differences when compared to the control group and they were dependent on the exposure time. No statistically significant differences were observed among the APDI groups at 1 and 3min of irradiation. On the other hand, 5min of APDI showed 99.85% of bacterial reduction (p=0.0004). In addition, the biofilm loose its structure following 5min APDI. CONCLUSIONS: The results of this study suggest that A. actinomycetemcomitans biofilm can be inactivated by MB mediated APDI.
BACKGROUND: The purpose of this study was to evaluate the antibacterial effects of photodynamic action of methylene blue (MB) against Aggregatibacter actinomycetemcomitans organized on biofilm. METHODS: After the biofilm growth in 96 flat-bottom well plate, the following groups were used: control group, untreated by either laser or photosensitizer (PS); MB group or dark toxicity group, which was exposed to MB alone (100μM) for 1min (pre-irradiation time); laser group, irradiated with laser for 5min in the absence of PS and three antimicrobial photodynamic inactivation (APDI) groups, with three exposure times of 1, 3 and 5min of irradiation, corresponding to fluences of 15, 45, and 75J/cm(2) respectively. The results were compared to the control group for statistical proposes. Scanning electronic microscope analysis was used to access structural changes in biofilm. RESULTS: Red laser alone and MB alone were not able to inactivate bacterial biofilm. APDI groups showed differences when compared to the control group and they were dependent on the exposure time. No statistically significant differences were observed among the APDI groups at 1 and 3min of irradiation. On the other hand, 5min of APDI showed 99.85% of bacterial reduction (p=0.0004). In addition, the biofilm loose its structure following 5min APDI. CONCLUSIONS: The results of this study suggest that A. actinomycetemcomitans biofilm can be inactivated by MB mediated APDI.
Authors: E T Carrera; H B Dias; S C T Corbi; R A C Marcantonio; A C A Bernardi; V S Bagnato; M R Hamblin; A N S Rastelli Journal: Laser Phys Date: 2016-11-09 Impact factor: 1.366
Authors: Ali Al-Ahmad; Aleksander Walankiewicz; Elmar Hellwig; Marie Follo; Christian Tennert; Annette Wittmer; Lamprini Karygianni Journal: Front Microbiol Date: 2016-11-28 Impact factor: 5.640