Guiding Escherichia Coli Biofilm Growth with Textured Surfaces

Biofilms represent complex 3D biological materials created by bacteria producing a protective matrix to survive in harsh environments. These bacteria exhibit a remarkable ability to adapt their matrix in response to various chemical, biological or physical stimuli. This implies that the materials properties of biofilms can be influenced by the properties of their substrate.<br/>The aim of this project is to regulate the growth and organization of biofilms by manipulating the geometry of their environment through structured surfaces, and to study how these micro-topographies affect the morphology and mechanical properties of the resulting biofilms.<br/>Therefore, we cultured <i>E. coli</i> bacteria of the AR3110 strain on salt-free agar plates for 5 days to obtain three-dimensional biofilms containing amyloid and phosphoethanolamine cellulose fibers. Additionally, 10 µm fluorescent beads may also be introduced to the bacterial solution to enable tracking of biofilm spreading <i>via</i> live fluorescence microscopy. Two days before inoculation, the surface of the agar plate is shaped with different PDMS stamps. The patterns on these stamps consist of parallel periodic lines or an array of concave half-spheres. In both cases, different dimensions are tested to determine if there is a critical length range where biofilms respond to these modifications, and how this affects their growth and properties. Our preliminary findings indicate that microtopography can remarkably influence biofilm spreading. Quantitative methods based on microscopy are now being established to characterize and measure these changes in a detailed manner. In the future, the utilization of structured substrates holds a great promise for the creation of oriented biofilm-based living materials with anisotropic properties.