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Photodynamic Inactivation of E. coli PTCC 1276 Using Light Emitting Diodes: Application of Rose Bengal and Methylene
Hasan Kariminezhad1, Hossein Amani2, Reza Khanbabaie3
1Department of Physics, Babol Noshirvani University of Technology, Babol, Iran. kariminezhad@nit.ac.ir.
Abstract:
The lack of a comparative study about potential of high-power light emitting diodes (LEDs) for photodynamic inactivation (PDI) of pathogenic microorganisms has remained as a challenging issue for researchers. Therefore, the aim of this study is to fill this gap through introduction of an efficient model for in vitro PDI in an aqueous medium. For this purpose, two individual 30 mW/cm2 irradiation systems were designed using suitable sets of green and red LEDs. At another work, Methylene blue (MB) and Rose bengal (RB) as two simple models in the range of 5-150 μM were used in order to compare PDI of E. coli PTCC 1276 using red and green LED systems. Our results showed that a first-order mathematical model has the strength to describe the temporal variation of survival curves. Based on our results, when concentration of photosensitizer increased, the rate of inactivation for RB increased while MB depicted a maximum rate value at 25 μM. In a comparative study, optimum inactivation of E. coli PTCC 1276 obtained during 2- and 10-min irradiation of the LED systems using RB and MB at 150 and 25 μM, respectively. With regard to lower value of inactivation time and higher rate of inactivation for RB, use of simultaneous green high-power LEDs and RB is proposed as an efficient approach for PDI of pathogenic bacteria in future industrial applications.
Insights
This study compares high-power LED systems for photodynamic inactivation (PDI) of E. coli. Green LEDs with Rose Bengal (RB) demonstrated faster bacterial inactivation than Methylene Blue (MB), offering an efficient PDI approach.
Area of Science:
- Photochemistry
- Microbiology
- Biomedical Engineering
Background:
- Limited comparative studies exist on high-power LED efficacy for photodynamic inactivation (PDI) of pathogens.
- Developing efficient PDI models is crucial for controlling microbial contamination.
Purpose of the Study:
- To establish an efficient in vitro model for PDI in aqueous media.
- To compare the efficacy of green and red LED systems with Methylene Blue (MB) and Rose Bengal (RB) for E. coli inactivation.
Main Methods:
- Designed two 30 mW/cm² irradiation systems using green and red LEDs.
- Investigated PDI of E. coli PTCC 1276 using MB and RB (5-150 μM).
- Applied a first-order mathematical model to analyze survival curve variations.
Main Results:
- RB's inactivation rate increased with concentration; MB showed a maximum rate at 25 μM.
- Optimal E. coli inactivation occurred with RB (150 μM) under green LEDs in 2 minutes and MB (25 μM) under red LEDs in 10 minutes.
- RB combined with green LEDs offered faster inactivation rates and shorter treatment times.
Conclusions:
- A first-order model effectively describes PDI kinetics.
- Green LEDs and RB present a highly efficient method for PDI of pathogenic bacteria.
- This approach holds promise for future industrial applications in microbial control.
