(a) Microscopic image showing the effective range of the plasma jet device applied to an E. coli bacterial lawn at a speed of 1 s/mm (4 runs). The dark area on the top and bottom represents the thick bacterial lawn. The light gray area in the center represents bacteria-free zone (3–4 mm); the inner line corresponds with the inner diameter of the nozzle. Scale bar: 1 mm. (b) Photographs of different bacterial lawns on agar plates after plasma application at a speed of 1 s/mm. (b0) Template showing treatment area for 1 to 7 min, (b1) S. mutans, (b2) P. aeruginosa, (b3) S. aureus, (b4) E. faecalis, (b5) E. coli.