4.7 Biofilms
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Fig. 4.31 Biofilm growth sequence. Each cell is colored according to its alignment with the vertical,
with horizontal cells shown in gray (Hartmann et al, 2018)
density for verticalization increases with the cell length, whence biofilms composed
of longer cells maintain a wider periphery of horizontal cells, and therefore yield
more rapidly expanding, flatter biofilms.
Two complementary close-up views of this process are presented in Figs. 4.31
and 4.32. Part of the observed biofilm growth series in Fig. 4.31 shows thousands of
individual cells, digitally colored according to their orientation. Figure 4.32 presents
Fig. 4.32 Accumulation of stress and vertical lift-off. (a)–(c) Simulation results of a growing
multilayered circular colony folding after reaching a critical radius. The stress accumulated in the
red-colored region results in vertical lifting of the biofilm. (d) Overall view of the observed biofilm.
(e) and (f) Accumulation of stress causes vertical lift-off. Red arrows indicate the directions of the
driving forces (Yaman et al, 2019)