Toward Ordered Materials Based on Self-Assembled Iridescent Cellulophaga lytica (C. lytica) Biofilms

The dimensions and gliding motility of some bacteria facilitate their self-assembly into iridescent biofilms. Coloration is a clearly visible indication of the crystalline arrangement of bacteria across multiple length scales within the biofilm. The ‘simplicity’ of prokaryotes increases the likelihood that such systems will be genetically tractable and amenable to tailoring through synthetic biology approaches. Taken together, these advantages suggest that iridescent biofilms may be a platform for making large scale, affordable, ‘green’ and field-friendly optical materials as well as tunable templates for ordered materials.<br/><br/>In the current study, we show that <i>C. lytica</i> 7489, given specific growth conditions, will generate intensely iridescent colonies. The utility of these biofilms in making materials is also considered. Specifically, we demonstrate that <i>C. lytica</i> biofilms are conducive to biofabrication approaches because they circumvent barriers currently preventing replication of ordered materials in industrial settings. By controlling the environmental conditions, we show that large monochrome biofilms can be generated, an indication of consistent cellular morphology and packing. The chemistry available on the surface of the cells is exploited to preserve and stabilize the biofilms.<br/><br/>The development of new classes of materials that are multi-scaled, lightweight, thermally insulating, selectively reflective, tough and manufacturable is of interest, though complex combinations of properties such as these can be challenging to achieve. The current work demonstrate that prokaryotic systems may serve as templates for such hierarchical materials.