Bacterial Photolithography: Patterning Escherichia coli Biofilms with High Spatial Control Using Photocleavable Adhesion Molecules

Abstract

Biofilms are not only a leading cause of chronic infections and biofouling, but they also have a tremendous positive potential in biotechnology for biocatalysis and waste treatment. Biofilms are spatially structured communities of microbes, which exchange chemicals and communicate with each other. By spatially controlling bacterial adhesion to surfaces, and therefore the microstructure of biofilms, a promising method of understanding social interactions between bacteria and designed biofilms is developed. The bacterial photolithography approach described here allows to photopattern specific bacteria adhesion molecules, to control surface adhesion, and to guide the formation of biofilms. To do this, α‐D‐mannoside, which is recognized by the Escherichia coli FimH receptor, is linked to a nonadhesive polyethylene glycol surface through a photocleavable 2‐nitrobenzyl linker. When a pattern of UV light in a specific shape is projected onto these surfaces, the light‐exposed areas become nonadhesive and bacteria only adhere to the dark, unexposed areas in the photopattern. Bacterial photolithography enables bacterial patterning with high spatial resolution down to 10 µm without mechanical interference. Additionally, patterning biofilms with complicated geometries allows studying the importance of microscale spatial organization on the collective behavior of bacteria such as quorum sensing.

Controlled spatial organization of bacterial clusters reveals cell filamentation is vital forXylella fastidiosabiofilm formation

“…The concept of cell density-dependent changes in cell behavior and phenotypes by DSFbased quorum sensing might underlie our observed cell density-dependent initiation of filamentous cell morphogenesis and directional cell growth 11,34,64 . In further support to this conjecture, previous observations in X. fastidiosa as well as in other bacteria and human cells have shown that quorum sensing mechanisms are activated upon exceeding a local DSF concentration threshold at regions of high cell densities 37,59,[65][66][67] Consistent with this model, a previous study using a X. fastidiosa…”

“…Selective and controlled spatial arrangement of cells and microcolonies are critical prerequisites for the investigation of dynamic biological phenomena of multicellular systems, such as cell plasticity, motility, morphogenesis, and cell-cell communication [35][36][37] . To this end, diverse approaches for selective cell organization with varying complexity and different surface chemical modifications have been previously developed 10,[37][38][39] . To simplify the approach, we exploited the native ability of X. fastidiosa to bind to specific chemical moieties with high efficacy.…”

Micro-biogeography greatly matters for competition: Continuous chaotic bioprinting of spatially-controlled bacterial microcosms

“…[29,39,40] Communication and/or synchronized behavior in bacterial communities are conceived as phenomena that mainly depend on the cell density and diversity of the species within the community. [12,31] However, a growing body of evidence suggests a paramount role as well for spatial positioning in bacterial societal behavior. [6–8,23,41,42]…”

“…For example, Hynes et al [30] accommodated spatially distinct aggregates of E. coli and Salmonella enterica using a casting-based method and suggested that interactions in this consortium may be influenced by spatial scales. Similarly, Chen et al [31] used photolithography to create patterns in adhesion polymers at a resolution of 10 µm. The patterns were subsequently used for specific anchoring of E. coli at those locations, and the authors then monitored bacterial crosstalk using a reporter gene activated by the high cell concentration in neighboring fronts.…”

Biofilm and swarming emergent behaviours controlled through the aid of biophysical understanding and tools

“…Increasing cell densities enhance bacteria motility [18,50] Inhomogeneous cell density patterns of living and dead cells shape biofilm's wrinkle architecture [58] and EPS production is thickness dependent [60] Light Light drives bulk swarm motility in phototactic bacteria and blue light can slow down cells and lead to local cell accumulation [65,66] Blue light can be used to pattern biofilms in genetically engineered cells or to induce biofilm dispersal through cell hyperpolarization [74][75][76][77]79] Mechanical patterning Geometric confinement induces vortex patterns useful to identify swarming motility [70,71] 3D printing and Menifluidics can direct biofilm growth with submillimetre precision [72,[81][82][83]…”