Fig. 2. Benzoselenadiazole D-amino acids can be incorporated into bacteria for light-controlled antimicrobial ablation.

a d-alanine is incorporated into the positions 4 or 5 of peptidoglycan structures. Incorporation followed by illumination results in the production of singlet oxygen and concomitant cell death (Gln: N-acetylglucosamine, Mur: N-acetylmuramic acid). b Synthesis of the amino acids 12 and 13 by conjugation of 4F with enantiomers of 2,3-diaminoproprionic acid. c Brightfield and fluorescence microscopy images of E. coli after incubation with compounds 12 and 13 (250 μM). Scale bar: 10 μm. The viability of bacterial cells was measured by optical density (600 nm) after incubation at 30 °C with or without compounds 12 or 13 and illumination using white LED. Data normalized to the viability of light-only treated cells and presented as mean values ± SEM (n = 2 independent experiments). d Time-lapse monitoring of E. coli that had been pretreated with NADA or compound 13 (both 100 μM). Representative brightfield and fluorescence microscope images (from three independent experiments) with excitation at 470 nm (196 mW) and 508 nm (62 mW) were taken every minute for 30 min. Green and red arrows indicate NADA- and 13-labeled bacteria, respectively; yellow arrowheads indicate exploding 13-labeled bacterial cells after treatment. Scale bar: 2 μm. Source data are available.