Figure 1

Optical setup of the UV inactivation system and emission spectrum of UV-LEDs. (a) Optical setup of the UV-LED inactivation system. (b) Emission spectra of 265 nm, 280 nm, and 308 nm UV-LEDs. These LEDs exhibited peak wavelength emissions at 266.5 nm, 280.6 nm, and 308.8 nm, respectively, with full-width at half-maximum bandwidths of 11.1 nm, 11.5 nm, and 12.0 nm. (c) Photograph of an E. coli bacterial sample irradiated by the UV-LED in an ultrasonic bath. An E. coli bacterial sample without UV irradiation was also placed in the ultrasonic bath as a control sample to account for the inactivation caused by ultrasonic vibrations.