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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.


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Schematic illustration of the experiment device.
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pone.0132445.g001: Schematic illustration of the experiment device.

Mentions: A continuous-wave laser device equipped with a laser diode (LD) of indium gallium nitride with a wavelength of 405 ± 5 nm (RV-1000; Ricoh Optical Industries, Hanamaki City, Japan) was used. The output power of the LD was set at 0, 350 and 700 mW corresponding to the irradiance of 0, 46 and 91 mW/cm2 at a distance of 85 mm from the LD, which was calculated by dividing the output power (mW) by the irradiation field size (cm2). An experimental device for ultrasound generation was identical to that used in our previous study [32]. The power of ultrasound was 30 W and the frequency was 1.65 MHz. A glass tube (15 mm in diameter and 85 mm long) containing a sample was set into the device so that the sample was exposed to the ultrasound irradiation from the transducer at the bottom and laser irradiation through an optical fiber at the top of the device. The temperature of the water bulk was controlled at 20 ± 1 °C. Schematic illustration of the device is shown in Fig 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)

Schematic illustration of the experiment device.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0132445.g001: Schematic illustration of the experiment device.
Mentions: A continuous-wave laser device equipped with a laser diode (LD) of indium gallium nitride with a wavelength of 405 ± 5 nm (RV-1000; Ricoh Optical Industries, Hanamaki City, Japan) was used. The output power of the LD was set at 0, 350 and 700 mW corresponding to the irradiance of 0, 46 and 91 mW/cm2 at a distance of 85 mm from the LD, which was calculated by dividing the output power (mW) by the irradiation field size (cm2). An experimental device for ultrasound generation was identical to that used in our previous study [32]. The power of ultrasound was 30 W and the frequency was 1.65 MHz. A glass tube (15 mm in diameter and 85 mm long) containing a sample was set into the device so that the sample was exposed to the ultrasound irradiation from the transducer at the bottom and laser irradiation through an optical fiber at the top of the device. The temperature of the water bulk was controlled at 20 ± 1 °C. Schematic illustration of the device is shown in Fig 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