Designing biofilm architecture through depletion-mediated self-assembly and emergent nematic order

Bacteria are ubiquitous and adaptable microorganisms that play crucial roles in the functioning of the ecosystem and hold immense potential for biotechnological applications. In nearly all environments, they form self-assembled biofilm communities. In this mini-review, we examine bacterial aggregation, focusing on two key aspects: the use of depletion forces to direct bacterial assembly and the emergence of liquid crystalline order in biofilms. We explore how the depletion attraction effect can be used to direct the assembly of bacteria into ordered groups, while also highlighting the diversity of ways different bacterial biofilms develop liquid crystal-like order and how it influences biofilm morphology and function. These phenomena offer promising avenues for manipulating bacterial communities and hold the potential to contribute to the development of design rules for engineering biofilms with tailored architectures and functionalities. This knowledge will ultimately expand our ability to harness biofilms for diverse applications in bioremediation, biomanufacturing, and medicine.