Spatio-temporal organization of matter during biofilm morphogenesis: the role of water

ZIEGE, RICARDO; PILZ-ALLEN, C; HENGGE, REGINE; LARGE, BASTIEN; BLANK, KERSTIN G.; BIDAN, CÉCILE M.; SCHULZE, BERIT; SERRA, DIEGO O.; FRATZL, PETER

Saarbrücken

Conferencia; Living Materials Conference 2020; 2020

Living Materials 2020 is organized in cooperation with Leibniz Health Technologies, a research alliance of the Leibniz Association.

Biofilms are living 3D structures forming as bacteria get embedded in a matrix of self-produced protein and polysaccharide fibers. Mechanical stresses introduced by the growth of a flat E. coli biofilm on a semi-solid agar substrate are released by the formation of wrinkles and folds.1,2 Surface instabilities could arise from differential growth strains at the interface of the biofilm and substrate. An increase in substrate humidity promotes growth and physical swelling of expanding biofilms which has been proposed to result from osmotic stress at the interface of substrate and biofilm.3 To clarify the interplay of substrate mechanics and biofilm spatio-temporal organization we aim at quantifying biofilm morphogenesis in a spatial and temporal manner depending on agar humidity. With time-lapse microscopy and automated image analysis, we analyze where active bacteria and extracellular polymeric substances accumulate during biofilm development. Preliminary results show spatio-temporally non-uniform composition of active and passive components on a macroscopic scale. Additionally, multi-particle tracking of fluorescent beads inside the biofilm allows us to report local deformation and growth behavior. After an initial lag phase, biofilm expansion is characterized by high strain rates and strong non-linear velocity profiles, which suggest important biofilm remodeling. Understanding biofilm morphogenesis can advance the design of new materials and structures involving surface instabilities.