Jonathan B Gillespie1, Michelle Maclean1,2, Martin J Given3, Mark P Wilson3, Martin D Judd3, Igor V Timoshkin1,3, Scott J MacGregor1,3. 1. 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom . 2. 2 Department of Biomedical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom . 3. 3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom .
Abstract
OBJECTIVE: This study investigates possible advantages in pulsed over continuous 405-nm light-emitting diode (LED) light for bacterial inactivation and energy efficiency. BACKGROUND: Alternative nonantibiotic methods of disinfection and infection control have become of significant interest. Recent studies have demonstrated the application of systems using 405-nm LEDs for continuous disinfection of the clinical environment, and also for potential treatment of contaminated wounds. METHODS: Liquid suspensions of 103 colony-forming units/mL populations of Staphylococcus aureus were subject to pulsed 405-nm light of different frequencies, duty cycles, and intensities and for different lengths of time. RESULTS: Pulsed exposures with the same average irradiance of 16 mW/cm2 and varying duty cycle (25%, 50%, 75%) showed very similar performance compared with continuous exposures, with 95-98% reduction of S. aureus achieved for all duty cycles. The pulsing frequency was varied in intervals from 100 Hz to 10 kHz and appeared to have little effect on antimicrobial efficacy. However, when comparing pulsed with continuous exposure, an improvement in inactivation per unit optical energy was achieved, with results showing an increase of approximately 83% in optical efficiency. CONCLUSIONS: These results suggest that under pulsed conditions, a lower energy consumption and lower perceived brightness could be achieved, thus potentially providing improved operating conditions for medical/infection control applications without compromising antimicrobial efficacy.
OBJECTIVE: This study investigates possible advantages in pulsed over continuous 405-nm light-emitting diode (LED) light for bacterial inactivation and energy efficiency. BACKGROUND: Alternative nonantibiotic methods of disinfection and infection control have become of significant interest. Recent studies have demonstrated the application of systems using 405-nm LEDs for continuous disinfection of the clinical environment, and also for potential treatment of contaminated wounds. METHODS: Liquid suspensions of 103 colony-forming units/mL populations of Staphylococcus aureus were subject to pulsed 405-nm light of different frequencies, duty cycles, and intensities and for different lengths of time. RESULTS: Pulsed exposures with the same average irradiance of 16 mW/cm2 and varying duty cycle (25%, 50%, 75%) showed very similar performance compared with continuous exposures, with 95-98% reduction of S. aureus achieved for all duty cycles. The pulsing frequency was varied in intervals from 100 Hz to 10 kHz and appeared to have little effect on antimicrobial efficacy. However, when comparing pulsed with continuous exposure, an improvement in inactivation per unit optical energy was achieved, with results showing an increase of approximately 83% in optical efficiency. CONCLUSIONS: These results suggest that under pulsed conditions, a lower energy consumption and lower perceived brightness could be achieved, thus potentially providing improved operating conditions for medical/infection control applications without compromising antimicrobial efficacy.
Authors: Praveen Ramakrishnan; Michelle Maclean; Scott J MacGregor; John G Anderson; M Helen Grant Journal: Toxicol In Vitro Date: 2016-02-23 Impact factor: 3.500
Authors: Stephen Wengraitis; Patrick McCubbin; Mary Margaret Wade; Tracey D Biggs; Shane Hall; Leslie I Williams; Alan W Zulich Journal: Photochem Photobiol Date: 2012-10-01 Impact factor: 3.421
Authors: M Maclean; S J Macgregor; J G Anderson; G A Woolsey; J E Coia; K Hamilton; I Taggart; S B Watson; B Thakker; G Gettinby Journal: J Hosp Infect Date: 2010-11 Impact factor: 3.926
Authors: Tianhong Dai; George P Tegos; Timur Zhiyentayev; Eleftherios Mylonakis; Michael R Hamblin Journal: Lasers Surg Med Date: 2010-01 Impact factor: 4.025
Authors: R S McDonald; S Gupta; M Maclean; P Ramakrishnan; J G Anderson; S J MacGregor; R M D Meek; M H Grant Journal: Eur Cell Mater Date: 2013-03-07 Impact factor: 3.942
Authors: Bahar Djouiai; Joanne E Thwaite; Thomas R Laws; Fabian M Commichau; Barbara Setlow; Peter Setlow; Ralf Moeller Journal: Appl Environ Microbiol Date: 2018-09-17 Impact factor: 4.792
Authors: Yucheng Wang; Ying Wang; Yuguang Wang; Clinton K Murray; Michael R Hamblin; David C Hooper; Tianhong Dai Journal: Drug Resist Updat Date: 2017-10-13 Impact factor: 18.500
Authors: Michelle Maclean; Monique P Gelderman; Sandhya Kulkarni; Rachael M Tomb; Caitlin F Stewart; John G Anderson; Scott J MacGregor; Chintamani D Atreya Journal: Front Med (Lausanne) Date: 2020-01-15
Authors: Jonathan T Butement; Daniel J Noel; Catherine A Bryant; Sandra A Wilks; Robert W Eason Journal: Front Microbiol Date: 2022-09-20 Impact factor: 6.064