LEDs and biomedical applications Aikaterini Argyraki Paul Michael

LEDs and biomedical applications Aikaterini Argyraki, Paul Michael Petersen DTU Fotonik, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde, Denmark Optimal illuminant for visual inspection of veins Aikaterini Argyraki, Line Katrine Harder Clemmensen, Paul Michael Petersen In the present study we provide empirical evidence and demonstrate statistically that white Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa biofilm illumination settings can affect the human ability to identify veins in the inner hand vasculature. A. Argyraki, M. Markvart , Anne Nielsen, T. Bjarnsholt , L. Bjørndal , P. M. Petersen It is shown that the ability to identify veins can, on average, be increased up to 24% when white In the present study the inactivation rate was studied as a function of dose for 24 h grown illumination settings that do not resemble incandescent light are applied. The illuminance biofilms. The dose was ramped from 72 J/m 2 to 10000 J/m 2. It was shown that UVB reported together with the effect of white illumination settings on direct visual perception of irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. biosamples are relevant for clinical investigations during the night (not disturbing the circadian No colony forming units (CFU) were observed for the UVB treated biofilms when the dose rhythm). was 10000 J/m 2 (CFU in control sample: 7. 5 x 104). UVB irradiation at a dose of 20040 J/m 2 A special LED lamp with high color rendering (CRI 84 -95) was developed and the effect of correlated color temperature (CCT) was evaluated, in the range between 2600 K and 5700 K at an illuminance level of 40± 9 lux on the ability of adult humans to identify veins. Effect of illumination p. value 0, 029<0, 05 Illumination Average vein Standard Average setting identification deviation of vein performance output identification improvement output % 1 (CCT 2600 K) 17. 1 2. 6 Not appl. 2 (CCT 3700 K) 19. 2 3. 5 12. 3 3 (CCT 4400 K) 18. 2 3. 5 6. 4 4 (CCT 4700 K) 20. 2 3. 5 18. 1 5 (CCT 4900 K) 19. 1 3. 5 11. 7 6 (CCT 5400 K) 18. 6 3. 5 8. 8 7 (CCT 5700 K) 18. 6 3. 5 8. 8 on mature biofilms (72 h grown) resulted in a 3. 9 log inactivation. The fact that the wavelength of 296 nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals and disinfection procedures during root canal treatment.