Many natural biological systems — such as biofilms, shells and skeletal tissues — are able to create multifunctional and environmentally responsive multiscale assemblies of living and non-living components. MIT MRSEC researchers have developed a synthetic-biology platform for engineering bacterial biofilms for the synthesis and patterning of non-living materials across multiple length scales. By using inducible genetic and cellular communication circuits to regulate Escherichia coli curli amyloid production, bacteria can be taught to organize amyloid fibrils at many different length scales. When these organized fibrils are combined with inorganic materials, such as gold nanoparticles (AuNPs) and quantum dots (QDs), it is possible to create an environmentally responsive biofilm-based electrical switch and to manipulate a wide range of new nanomaterials including gold nanowires and nanorods, and fluorescent quantum dots co-localized with gold nanoparticles. This work lays a foundation for synthesizing, patterning, and controlling functional “living” materials containing engineered cells and non-living materials.