Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS

Ultraviolet light emitting diodes (UV-LEDs) have shown a great potential to replace traditional UV lamps for microorganisms disinfection. Most research is focused on water and food disinfection applications whereas the utilization of UVLEDs for healthcare disinfection is not fully understood due to...

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Main Author:	Malik, Sameen Ahmed
Format:	Thesis
Language:	English
Published:	2020
Subjects:	Q Science (General) R Medicine (General)
Online Access:	http://eprints.utm.my/id/eprint/98227/1/SameenAhmedMalikPSBME2020.pdf
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spelling	my-utm-ep.982272022-11-23T07:57:19Z Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS 2020 Malik, Sameen Ahmed Q Science (General) R Medicine (General) Ultraviolet light emitting diodes (UV-LEDs) have shown a great potential to replace traditional UV lamps for microorganisms disinfection. Most research is focused on water and food disinfection applications whereas the utilization of UVLEDs for healthcare disinfection is not fully understood due to limited exploration on this area. This study presented a comprehensive work on UV-LEDs solitary and coupled wavelength combinations in the context of inactivation, photoreactivation and morphological characteristics which is of significance to expand UV-LEDs scope beyond water applications, specifically to be adopted in healthcare disinfection system. In this study, UV-LEDs with peak emission at 276, 311 and 364 nm were studied for the inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Under the solitary wavelength, the effectiveness of each LED was studied separately and the effects of varied exposure times as well as UV doses were investigated for the inactivation of E. coli and S. aureus. It was found that the 276 nm LED produced the highest inactivation efficiency as compared to the 311 and 364 nm LEDs which required significantly lower exposure time and UV dose to achieve maximum inactivation of both bacteria. In the focus of investigating the effects of coupled wavelengths, simultaneously, the coupled triadic wavelength (SCTW) 276\|311\|364 nm UV-LEDs enhanced the inactivation effects and was able to produce the highest inactivation of E. coli (98.42%) and S. aureus (99.34%). The combination of 276\|311 nm achieved the second best results on E. coli (97.36%) and S. aureus (98.63%), followed by the 276, 276\|364, 311, 311\|364 and 364 nm, respectively. For both, the solitary and the coupled wavelengths, a relatively higher inactivation of S. aureus was found in comparison with E. coli, indicating that S. aureus was more sensitive to UV irradiation. Moreover, the evaluation of morphological images of E. coli and S. aureus showed that all UV treated samples caused significant damage and deterioration of cellular membranes. However, the most pronounced damages such as membrane transparency, pore formation, blebs protrusion and lysis were seen when both bacteria were treated with the SCTW 276\|311\|364 nm UV-LEDs. The results also showed that the SCTW 276\|311\|364 nm UV-LEDs was the most effective combination in providing better persistence against the photoreactivation of E. coli (1.75%) and S. aureus (4.29%) as compared to the 276 nm which projected the photoreactivation of 2.14% on E. coli and 8.92% on S. aureus. These results are of significance for future applications in healthcare. 2020 Thesis http://eprints.utm.my/id/eprint/98227/ http://eprints.utm.my/id/eprint/98227/1/SameenAhmedMalikPSBME2020.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:144880 phd doctoral Universiti Teknologi Malaysia, Faculty of Engineering - School of Biomedical Engineering & Health Sciences Faculty of Engineering - School of Biomedical Engineering & Health Sciences
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	Q Science (General) R Medicine (General)
spellingShingle	Q Science (General) R Medicine (General) Malik, Sameen Ahmed Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS
description	Ultraviolet light emitting diodes (UV-LEDs) have shown a great potential to replace traditional UV lamps for microorganisms disinfection. Most research is focused on water and food disinfection applications whereas the utilization of UVLEDs for healthcare disinfection is not fully understood due to limited exploration on this area. This study presented a comprehensive work on UV-LEDs solitary and coupled wavelength combinations in the context of inactivation, photoreactivation and morphological characteristics which is of significance to expand UV-LEDs scope beyond water applications, specifically to be adopted in healthcare disinfection system. In this study, UV-LEDs with peak emission at 276, 311 and 364 nm were studied for the inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Under the solitary wavelength, the effectiveness of each LED was studied separately and the effects of varied exposure times as well as UV doses were investigated for the inactivation of E. coli and S. aureus. It was found that the 276 nm LED produced the highest inactivation efficiency as compared to the 311 and 364 nm LEDs which required significantly lower exposure time and UV dose to achieve maximum inactivation of both bacteria. In the focus of investigating the effects of coupled wavelengths, simultaneously, the coupled triadic wavelength (SCTW) 276\|311\|364 nm UV-LEDs enhanced the inactivation effects and was able to produce the highest inactivation of E. coli (98.42%) and S. aureus (99.34%). The combination of 276\|311 nm achieved the second best results on E. coli (97.36%) and S. aureus (98.63%), followed by the 276, 276\|364, 311, 311\|364 and 364 nm, respectively. For both, the solitary and the coupled wavelengths, a relatively higher inactivation of S. aureus was found in comparison with E. coli, indicating that S. aureus was more sensitive to UV irradiation. Moreover, the evaluation of morphological images of E. coli and S. aureus showed that all UV treated samples caused significant damage and deterioration of cellular membranes. However, the most pronounced damages such as membrane transparency, pore formation, blebs protrusion and lysis were seen when both bacteria were treated with the SCTW 276\|311\|364 nm UV-LEDs. The results also showed that the SCTW 276\|311\|364 nm UV-LEDs was the most effective combination in providing better persistence against the photoreactivation of E. coli (1.75%) and S. aureus (4.29%) as compared to the 276 nm which projected the photoreactivation of 2.14% on E. coli and 8.92% on S. aureus. These results are of significance for future applications in healthcare.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Malik, Sameen Ahmed
author_facet	Malik, Sameen Ahmed
author_sort	Malik, Sameen Ahmed
title	Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS
title_short	Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS
title_full	Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS
title_fullStr	Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS
title_full_unstemmed	Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS
title_sort	effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength uv-leds
granting_institution	Universiti Teknologi Malaysia, Faculty of Engineering - School of Biomedical Engineering & Health Sciences
granting_department	Faculty of Engineering - School of Biomedical Engineering & Health Sciences
publishDate	2020
url	http://eprints.utm.my/id/eprint/98227/1/SameenAhmedMalikPSBME2020.pdf
_version_	1776100560704897024

Effectiveness of multivariate parameters on medical device disinfection using simultaneously-coupled triadic wavelength UV-LEDS

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