Characterizing and tuning the bacterial synthetic adhesion biophysics for biomaterial applications.

Abstract

Bacterial synthetic multi-cellular (SMC) systems present promising characteristics as engineering platforms for developing complex products in the areas of medicine, biosynthesis and smart materials. This work has been recently advanced by the development of a genetically encoded toolkit of surface-bound nanobodies and antigens via the intimin autotransporter in E. coli that can enable precise manipulation of cell-cell adhesion and design of self-assembled multicellular patterns. However, it is necessary to be able to predict how adhering cells behave inside synthetic consortia and more specifically, how the adhesins behave on the surface of each of these cells, in order to advance the functionality of the adhesin toolkit at the subcellular level. We quantitatively measured the key biophysical (kinetic) parameters that determine dynamics (and mechanics) of the synthetic adhesins on the cell surface, such as the lateral diffusion coefficient, the production and degradation rates and the binding force between two complementary adhesins. The complete characterization of the adhesin construct enables us to further their application in the field of engineered living materials (ELMs). We show that tuning the adhesin biophysical parameters at a microscopic level can change the biomaterial properties at a macroscopic level. These results are critical for rational engineering and modeling synthetic adhesins and ultimately multicellular synthetic consortia and will also be valuable for researchers working with this intimin and potentially other autotransporter and nanobodies in various other contexts by providing the methodology for the characterization of future synthetic adhesins.