Figure 5. Biofilms generate large traction forces.

(A) Traction force microscopy measurements at the hydrogel-biofilm interface. The dashed line shows the edge of the biofilm. Traction force is largest at the biofilm center, reaching 100 kPa. (B) Deformation profiles generated by V. cholerae Rg biofilms of equal diameters on three hydrogels with different stiffness. (C) Biofilm diameter-dependence of maximum deformation for four different hydrogel composition representing a typical range of tissue stiffnesses. The softest hydrogel can deform up to 80 µm for a biofilm diameter of 220 µm. Data points correspond to different biofilms grown in one microfluidic chamber. Scale bar: 20 µm.

Figure 5—figure supplement 1. Biofilm diameter-dependence of λ for substrates with different moduli.

λ scales linearly and it is not substrate-stiffness dependent.

Figure 5—figure supplement 2. Power-law relationship between deformation ${\delta }_{max}$ and substrate moduli (E).

Values for δ_max/r were extrapolated from linear regression of the data points in Figure 5C for r = 50 µm (d = 100 µm).