A de novo matrix for macroscopic living materials from bacteria

Abstract

Engineered living materials (ELMs) embed living cells in a biopolymer matrix to create novel materials with tailored functions. While bottom-up assembly of macroscopic ELMs with a de novo matrix would offer the greatest control over material properties, we lack the ability to genetically encode a protein matrix that leads to collective self-organization. Here we report growth of ELMs from Caulobacter crescentus cells that display and secrete a self-interacting protein. This protein formed a de novo matrix and assembled cells into centimeter-scale ELMs. Discovery of design and assembly principles allowed us to tune the mechanical, catalytic, and morphological properties of these ELMs. This work provides novel tools, design and assembly rules, and a platform for growing ELMs with control over matrix and cellular structure and function.One-Sentence SummaryWe discovered rules to grow bacteria into macroscopic living materials with customizable composition, structure, and function.

Engineered Living Hydrogels

“…Engineering the biosynthetic pathways of microbial cells via genes and culture environments provides opportunities to regulate the structures and properties of the material produced. [35,131] The ability to engineer microbial cells to produce biopolymers and generate hydrogel materials depends on understanding biopolymer synthesis and secretion pathways. For metabolic engineering, the first step is to quantify metabolic pathways, enzyme kinetics, and cell growth rates (Figure 7a).…”

“…[148,149] Cell culture conditions can be used to adjust the structures of cell-generated materials. [131] The common bacterial cellulose pellicle is a flat-sheet structure floating at the interface between the culture medium and air (Figure 8b). [39] Spherical particles of bacterial cellulose can be generated in an agitated culture (diameter: 0.5-8 mm), in contrast to the flat sheet grown on a static culture.…”

“…Engineering the biosynthetic pathways of microbial cells via genes and culture environments provides opportunities to regulate the structures and properties of the material produced. [ 35,131 ]…”