Limits...
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

Yield of ·OH by photolysis of H2O2 with or without ultrasound irradiation.Each value represents the mean of three independent assays with the standard deviation.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4493093&req=5

pone.0132445.g003: Yield of ·OH by photolysis of H2O2 with or without ultrasound irradiation.Each value represents the mean of three independent assays with the standard deviation.

Mentions: The result of ESR determination of ·OH is summarized in Fig 3. When different concentrations of H2O2 containing 300 mM DMPO were exposed to the laser irradiation with or without ultrasound irradiation for 1 min, the ESR signal of DMPO-OH was detected. The DMPO-OH signal was confirmed by the hyperfine coupling constant (aN = 1.49; aH = 1.49 mT) as reported in a previous study [40]. The yield of DMPO-OH generated by the photolysis of H2O2 increased dependently on the concentration of H2O2 and the laser power. When 1 M H2O2 was irradiated with laser at 700 mW without ultrasound irradiation, the yield of DMPO-OH reached approximately 30 μM. By contrast, the yield of DMPO-OH generated by ultrasound irradiation alone was not changed with the concentration of H2O2 and was almost as much as that generated by the laser irradiation of 1 M H2O2 at 700 mW. Accordingly, the yield of DMPO-OH increased additively when H2O2 was concomitantly irradiated with laser and ultrasound. For instance, around 60 μM DMPO-OH was yielded when 1 M H2O2 was concomitantly irradiated with laser at 700 mW and ultrasound.


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)

Yield of ·OH by photolysis of H2O2 with or without ultrasound irradiation.Each value represents the mean of three independent assays with the standard deviation.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0132445.g003: Yield of ·OH by photolysis of H2O2 with or without ultrasound irradiation.Each value represents the mean of three independent assays with the standard deviation.
Mentions: The result of ESR determination of ·OH is summarized in Fig 3. When different concentrations of H2O2 containing 300 mM DMPO were exposed to the laser irradiation with or without ultrasound irradiation for 1 min, the ESR signal of DMPO-OH was detected. The DMPO-OH signal was confirmed by the hyperfine coupling constant (aN = 1.49; aH = 1.49 mT) as reported in a previous study [40]. The yield of DMPO-OH generated by the photolysis of H2O2 increased dependently on the concentration of H2O2 and the laser power. When 1 M H2O2 was irradiated with laser at 700 mW without ultrasound irradiation, the yield of DMPO-OH reached approximately 30 μM. By contrast, the yield of DMPO-OH generated by ultrasound irradiation alone was not changed with the concentration of H2O2 and was almost as much as that generated by the laser irradiation of 1 M H2O2 at 700 mW. Accordingly, the yield of DMPO-OH increased additively when H2O2 was concomitantly irradiated with laser and ultrasound. For instance, around 60 μM DMPO-OH was yielded when 1 M H2O2 was concomitantly irradiated with laser at 700 mW and ultrasound.

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