Micro-CT X-ray imaging exposes structured diffusion barriers within biofilms

Imaging and quantifying calcium-rich structures in B. subtilis colonies. B. subtilis and M. smegmatis colonies grown on 1.5% B4 agar, supplemented with Ca acetate, as indicated in the main text. a Left panel—3D reconstruction. Middle panel—segmentation of the reconstructed volume, red indicates the densest mineral. Right panel—transversal slices. Scale bar: 200？μm. b Relative volume of the mineral layer of the total B. subtilis colony volume. Averages of three independent experiments are displayed, and the bars represent standard deviation. c TGA analysis of calcium minerals in B. subtilis colonies. Averages of three independent experiments are displayed, and the bars represent standard deviation. d Estimated thickness of the mineral layer in B. subtilis colony. Averages of three independent experiments are displayed, and the bars represent standard deviatio