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Bactericidal Effect of Photolysis of H2O2 in Combination with Sonolysis of Water via Hydroxyl Radical Generation.

Sheng H, Nakamura K, Kanno T, Sasaki K, Niwano Y - PLoS ONE (2015)

Bottom Line: The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone.These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic.Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA.

View Article: PubMed Central - PubMed

Affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.

ABSTRACT
The bactericidal effect of hydroxyl radical (·OH) generated by combination of photolysis of hydrogen peroxide (H2O2) and sonolysis of water was examined under the condition in which the yield of ·OH increased additively when H2O2 aqueous solution was concomitantly irradiated with laser and ultrasound. The suspension of Staphylococcus aureus mixed with the different concentrations of H2O2 was irradiated simultaneously with a laser light (wavelength: 405 nm, irradiance: 46 and 91 mW/cm2) and ultrasound (power: 30 w, frequency: 1.65 MHz) at 20 ± 1°C of the water bulk temperature for 2 min. The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone. By contrast, the ultrasound irradiation alone exerted almost no bactericidal effect. These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic. A multi-way analysis of variance also revealed that the interaction of H2O2 concentration, laser power and ultrasound irradiation significantly affected the bactericidal activity. Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA.

No MeSH data available.


Related in: MedlinePlus

Comparison of bactericidal activity of photolysis of H2O2 with or without ultrasound irradiation.Each value represents the mean of six independent assays with standard deviation. Statistical analysis was conducted at each LD output power. Significant difference (p<0.01) between the two groups is demonstrated by the different alphabetical letter (i.e., bars with the same letter are not significantly different).
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pone.0132445.g002: Comparison of bactericidal activity of photolysis of H2O2 with or without ultrasound irradiation.Each value represents the mean of six independent assays with standard deviation. Statistical analysis was conducted at each LD output power. Significant difference (p<0.01) between the two groups is demonstrated by the different alphabetical letter (i.e., bars with the same letter are not significantly different).

Mentions: The result of bactericidal assay is summarized in Fig 2. Ultrasound irradiation of H2O (0 M H2O2) and 0.25–1 M H2O2 without laser irradiation (LD 0 mW) exerted almost no bactericidal effect within 2 min treatment. However, combination of laser and ultrasound irradiation significantly reduced the CFU in comparison with laser irradiation of H2O2 (1 M H2O2 at 350 mW, and 0.25–1 M H2O2 at 700 mW). For instance, comparing the bactericidal activity of laser irradiation of 0.5 M H2O2 alone (700 mW) for 2 min, which killed the bacteria only with a >1-log reduction of CFU/mL, the combination of ultrasound and laser irradiation of 0.5 M H2O2 killed bacteria with a 3-log reduction of CFU/mL on average. In addition, a multi-way ANOVA showed that the bactericidal activity was significantly affected by the interaction of H2O2 concentration, laser power and ultrasound irradiation (Table 1).


Bactericidal Effect of Photolysis of H2O2 in Combination with Sonolysis of Water via Hydroxyl Radical Generation.

Sheng H, Nakamura K, Kanno T, Sasaki K, Niwano Y - PLoS ONE (2015)

Comparison of bactericidal activity of photolysis of H2O2 with or without ultrasound irradiation.Each value represents the mean of six independent assays with standard deviation. Statistical analysis was conducted at each LD output power. Significant difference (p<0.01) between the two groups is demonstrated by the different alphabetical letter (i.e., bars with the same letter are not significantly different).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493093&req=5

pone.0132445.g002: Comparison of bactericidal activity of photolysis of H2O2 with or without ultrasound irradiation.Each value represents the mean of six independent assays with standard deviation. Statistical analysis was conducted at each LD output power. Significant difference (p<0.01) between the two groups is demonstrated by the different alphabetical letter (i.e., bars with the same letter are not significantly different).
Mentions: The result of bactericidal assay is summarized in Fig 2. Ultrasound irradiation of H2O (0 M H2O2) and 0.25–1 M H2O2 without laser irradiation (LD 0 mW) exerted almost no bactericidal effect within 2 min treatment. However, combination of laser and ultrasound irradiation significantly reduced the CFU in comparison with laser irradiation of H2O2 (1 M H2O2 at 350 mW, and 0.25–1 M H2O2 at 700 mW). For instance, comparing the bactericidal activity of laser irradiation of 0.5 M H2O2 alone (700 mW) for 2 min, which killed the bacteria only with a >1-log reduction of CFU/mL, the combination of ultrasound and laser irradiation of 0.5 M H2O2 killed bacteria with a 3-log reduction of CFU/mL on average. In addition, a multi-way ANOVA showed that the bactericidal activity was significantly affected by the interaction of H2O2 concentration, laser power and ultrasound irradiation (Table 1).

Bottom Line: The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone.These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic.Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA.

View Article: PubMed Central - PubMed

Affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.

ABSTRACT
The bactericidal effect of hydroxyl radical (·OH) generated by combination of photolysis of hydrogen peroxide (H2O2) and sonolysis of water was examined under the condition in which the yield of ·OH increased additively when H2O2 aqueous solution was concomitantly irradiated with laser and ultrasound. The suspension of Staphylococcus aureus mixed with the different concentrations of H2O2 was irradiated simultaneously with a laser light (wavelength: 405 nm, irradiance: 46 and 91 mW/cm2) and ultrasound (power: 30 w, frequency: 1.65 MHz) at 20 ± 1°C of the water bulk temperature for 2 min. The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone. By contrast, the ultrasound irradiation alone exerted almost no bactericidal effect. These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic. A multi-way analysis of variance also revealed that the interaction of H2O2 concentration, laser power and ultrasound irradiation significantly affected the bactericidal activity. Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA.

No MeSH data available.


Related in: MedlinePlus