scholarly journals Evaluation of Photodynamic Inactivation Efficiency Using Conventional and Decorative Light-Emitting Diode Lamps

2017 ◽  
pp. 1569
Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 530
Author(s):  
Joe Heffron ◽  
Matthew Bork ◽  
Brooke K. Mayer ◽  
Troy Skwor

Effective broad-spectrum antiviral treatments are in dire need as disinfectants and therapeutic alternatives. One such method of disinfection is photodynamic inactivation, which involves the production of reactive oxygen species from dissolved oxygen in response to light-stimulated photosensitizers. This study evaluated the efficacy of functionalized porphyrin compounds for photodynamic inactivation of bacteriophages as human virus surrogates. A blue-light light emitting diode (LED) lamp was used to activate porphyrin compounds in aqueous solution (phosphate buffer). The DNA bacteriophages ΦX174 and P22 were more resistant to porphyrin TMPyP photodynamic inactivation than RNA bacteriophage fr, with increasing rates of inactivation in the order: ΦX174 << P22 << fr. Bacteriophage ΦX174 was therefore considered a resistant virus suitable for the evaluation of three additional porphyrins. These porphyrins were synthesized from TMPyP by inclusion of a central palladium ion (PdT4) and/or the addition of a hydrophobic C14 chain (PdC14 or C14). While the inactivation rate of bacteriophage ΦX174 via TMPyP was similar to previous reports of resistant viruses, ΦX174 inactivation increased by a factor of approximately 2.5 using the metalloporphyrins PdT4 and PdC14. The order of porphyrin effectiveness was TMPyP < C14 < PdT4 < PdC14, indicating that both Pd2+ ligation and C14 functionalization aided virus inactivation.


2021 ◽  
Vol 8 (3) ◽  
pp. 124-130
Author(s):  
T Purushothaman ◽  
K Irfana Mol

The light-emitting diode (LED) is an advanced technology with a wide range of applications in our day-to-day life. It has numerous advantages over conventional light, such as controlling the spectrum of light, the specificity of the wavelength, cool emitting surface, and cost-effectiveness. The novel technologies and developments have proved the efficacy of LEDs in eliminating microbes rather than being an effective lighting source. The LED employs Photodynamic Inactivation to eliminate micro-organisms with the help of various photo-sensitizers. Photodynamic inactivation is a non-chemical based technique that helps fight against the microbes without developing the resistant microbial strains. The illumination of LED at a specific narrow wavelength exhibits antimicrobial activity against a wide range of microbes, including resistant strains. Getting rid of harmful micro-organisms is one of the effective ways to reduce health risks and promote quality of life. Hence, the LEDs with specific narrow wavelengths can be employed to sterilize the medical equipment, healthcare environment, and food preservation without using chemicals. The Photodynamic Inactivation using LED as a light source will be a promising source for eradicating harmful micro-organisms, including nosocomial and foodborne pathogens.


2020 ◽  
Vol 23 (2) ◽  
Author(s):  
Maria Ângela Lacerda Rangel Esper ◽  
Junia Oliveira Barbosa ◽  
Janaína De Araújo Alvarenga ◽  
Juliana Campos Junqueira ◽  
Alessandra nara De Souza Rastelli ◽  
...  

Objective: The aim of this in vitro study was to evaluate the efficacy of photodynamic inactivation (PDI) with erythrosine (E), using a light-emitting diode (LED) on planktonic cultures of Streptococcus mutans. Material and Methods: A Streptococcus mutans strain (UA 159) was used to prepare the suspensions containing 107 cells/mL, which was tested under different experimental conditions: a) LED irradiation in the presence of erythrosine as a photosensitizer (E+L+); b) LED irradiation only (P-L+); c) treatment with erythrosine only (E+L-); and d) no LED irradiation or photosensitizer (P) treatment, which served as a control group (P-L-). After treatment, strains were seeded onto MSBS agar for determination of the number of colony-forming units (CFU/mL). Results: The results were submitted to analysis of variance and the Tukey test (p < 0.05). No reduction in the number of CFU/mL was observed in the treatment group with erythrosine (E+L+) when compared to the control (P-L-). Conclusion: PDI using erythrosine did not reduce the number of CFUs per millimeter within the parameters in this study.KEYWORDSErythrosine; Decay; Photodynamic inactivation; Light-emitting diode.


2020 ◽  
pp. 144-148

Chaos synchronization of delayed quantum dot light emitting diode has been studied theortetically which are coupled via the unidirectional and bidirectional. at synchronization of chaotic, The dynamics is identical with delayed optical feedback for those coupling methods. Depending on the coupling parameters and delay time the system exhibits complete synchronization, . Under proper conditions, the receiver quantum dot light emitting diode can be satisfactorily synchronized with the transmitter quantum dot light emitting diode due to the optical feedback effect.


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