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Effects of Carbon Dioxide Aerosols on the Viability of Escherichia coli during Biofilm Dispersal.

Singh R, Monnappa AK, Hong S, Mitchell RJ, Jang J - Sci Rep (2015)

Bottom Line: A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces.Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet.In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm.

View Article: PubMed Central - PubMed

Affiliation: School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, S. Korea.

ABSTRACT
A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces. However, the impact of the aerosols on the viability of bacteria during treatment has never been evaluated. In this study, the effects of high-speed CO2 aerosols, a mixture of solid and gaseous CO2, on bacteria viability was studied. It was found that when CO2 aerosols were used to disperse biofilms of Escherichia coli, they led to a significant loss of viability, with approximately 50% of the dispersed bacteria killed in the process. By comparison, 75.6% of the biofilm-associated bacteria were viable when gently dispersed using Proteinase K and DNase I. Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet. In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm. As such, these CO2 aerosols not only remove biofilm-associated bacteria effectively but also significantly impact their viability by disrupting membrane integrity.

No MeSH data available.


Related in: MedlinePlus

Schematic illustration of the system used in this study to expose bacterial biofilms to CO2 aerosols and capture dispersed cells29.
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f5: Schematic illustration of the system used in this study to expose bacterial biofilms to CO2 aerosols and capture dispersed cells29.

Mentions: The general experimental procedures employed were published previously1920. Briefly, the biofilms on the silicon chips were washed gently with 10 mM ammonium acetate buffer (Sigma-Aldrich, USA), and were treated with the aerosols immediately. We placed the E. coli biofilm grown chips horizontally and positioned 2 cm from the nozzle in an aerosol flow. The nozzle axis was maintained at 40° angle relative to the chip surface. The bacteria dispersed by the aerosol treatment were collected using a 200 ml bottle arranged over the chip to minimize loss (Fig. 5). A dual gas unit (K6-10DG; Applied Surface Technologies, NJ, USA) was used for aerosol generation. The N2 gas pressure was 0.7 MPa and the CO2 gas pressure was 5.6 ± 0.2 MPa. The CO2 aerosols were off for 3 seconds during each 8-second cleaning cycle, and the total cleaning time was 5 cycles. The average room temperature was 25.2 (±2.1) °C, and the average relative humidity was 67.5 (±7.3) % during all aerosol treatments.


Effects of Carbon Dioxide Aerosols on the Viability of Escherichia coli during Biofilm Dispersal.

Singh R, Monnappa AK, Hong S, Mitchell RJ, Jang J - Sci Rep (2015)

Schematic illustration of the system used in this study to expose bacterial biofilms to CO2 aerosols and capture dispersed cells29.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561891&req=5

f5: Schematic illustration of the system used in this study to expose bacterial biofilms to CO2 aerosols and capture dispersed cells29.
Mentions: The general experimental procedures employed were published previously1920. Briefly, the biofilms on the silicon chips were washed gently with 10 mM ammonium acetate buffer (Sigma-Aldrich, USA), and were treated with the aerosols immediately. We placed the E. coli biofilm grown chips horizontally and positioned 2 cm from the nozzle in an aerosol flow. The nozzle axis was maintained at 40° angle relative to the chip surface. The bacteria dispersed by the aerosol treatment were collected using a 200 ml bottle arranged over the chip to minimize loss (Fig. 5). A dual gas unit (K6-10DG; Applied Surface Technologies, NJ, USA) was used for aerosol generation. The N2 gas pressure was 0.7 MPa and the CO2 gas pressure was 5.6 ± 0.2 MPa. The CO2 aerosols were off for 3 seconds during each 8-second cleaning cycle, and the total cleaning time was 5 cycles. The average room temperature was 25.2 (±2.1) °C, and the average relative humidity was 67.5 (±7.3) % during all aerosol treatments.

Bottom Line: A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces.Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet.In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm.

View Article: PubMed Central - PubMed

Affiliation: School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, S. Korea.

ABSTRACT
A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces. However, the impact of the aerosols on the viability of bacteria during treatment has never been evaluated. In this study, the effects of high-speed CO2 aerosols, a mixture of solid and gaseous CO2, on bacteria viability was studied. It was found that when CO2 aerosols were used to disperse biofilms of Escherichia coli, they led to a significant loss of viability, with approximately 50% of the dispersed bacteria killed in the process. By comparison, 75.6% of the biofilm-associated bacteria were viable when gently dispersed using Proteinase K and DNase I. Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet. In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm. As such, these CO2 aerosols not only remove biofilm-associated bacteria effectively but also significantly impact their viability by disrupting membrane integrity.

No MeSH data available.


Related in: MedlinePlus