Many natural biological systems—such as biofilms, shells and skeletal tissues—are able to assemble multifunctional and environmentally responsive multiscale assemblies of living and non-living components. Here, by using inducible genetic circuits and cellular communication circuits to regulate Escherichia coli curli amyloid production, we show that E. coli cells can organize self-assembling amyloid fibrils across multiple length scales, producing amyloid-based materials that are either externally controllable or undergo autonomous patterning. We also interfaced curli fibrils with inorganic materials, such as gold nanoparticles (AuNPs) and quantum dots (QDs), and used these capabilities to create an environmentally responsive biofilm-based electrical switch, produce gold nanowires and nanorods, co-localize AuNPs with CdTe/CdS QDs to modulate QD fluorescence lifetimes, and nucleate the formation of fluorescent ZnS QDs. This work lays a foundation for synthesizing, patterning, and controlling functional composite materials with engineered cells. Biofilms are multifunctional and environmentally responsive assemblies of living and non-living components. By using synthetic gene networks in engineered cells to regulate the production of extracellular amyloid fibrils, and by interfacing the fibrils with inorganic materials such as metal nanoparticles, stimuli-responsive synthetic biofilms with switchable functions and tunable composition and structure have now been produced.

Synthesis and patterning of tunable multiscale materials with engineered cells