FIGURE 4.

Effect of 80 ppm gNO₂ on biofilm formation. (A) CLSM images of 24 h biofilms formed by bacteria after air or 80 ppm gNO₂ exposure. For each biofilm, a 3D view along the x, y, and z-axes is displayed. Images show representative data from at least five independent biofilm assays. Scale bars = 20 μm. (B) COMSTAT2 image analyses were performed to determine the ratio (NO₂/Air) of biovolume (μm³/μm²), average thickness (μm), and roughness coefficient (Ra). Error bars show standard error of the mean of independent treatments (n ≥ 5). Statistical significance was calculated by a ratio paired t-test. (^∗) for P < 0.05, (^∗∗) for P < 0.01, and (^∗∗∗) for P < 0.001.