Figure 5

C. lytica can be used as an iridescent bioink. (A) 3D printed designs containing C. lytica were generated on agar using an Allevi 3 Bioprinter setup (A-i to A-iv). As previously shown for dispersed biofilms, increased salinity red shifts the C. lytica ink’s reflection. (Supplemental fig. 9) (B) SEM image of edge of 3D printed biofilm showing ordered cells of the printed biofilm. (C, D) C. lytica trace the edges of a paper template (e.g. schematic in C-i). The red circle on the template design indicates the site of inoculation. Cells behave like a self-printing bioink to write various patterns in ambient conditions. (B) Increasing the agar concentration from 1.0% (C-ii) to 1.5% (C-iii) reduces the width of the tracing as revealed in Keyence measurements (C-iv). This result suggests that gliding motility is modulated in a way that confines the cells closer to the template on the higher concentration agar. (D) Additional tracings show BACTracing can be used with shapes of varying complexity, angles and connections. Agar concentration can be used to confine the traces when the distance between features is small as is the case in intricate patterns such as the Air Force Symbol (supplemental Fig. 6c). (E) Template of a complex pattern (i) and its BACTraced counterpart (ii) after fixation showing that the iridescent pattern can be preserved.