Selective Covalent Assembly of Gram-Negative Bacteria and Synthetic Polymers into Functional Living Materials

Here, we report selective covalent assembly of Gram-negative bacteria and synthetic polymers into functional living materials. We discovered that triblock polymers decorated with vinyl sulfone (VS), a motif that forms a stable covalent bond with cysteine residues on surface proteins, yielded stable covalent assembly with bacterial cells. Notably, we found that these assemblies were uniquely cell-type-specific, occurring only in Gram-negative bacteria, highlighting differences in surface structures and the macromolecular diffusion barrier across bacterial species. We also demonstrated that assembling engineered cells into materials results in situ melanin production from living materials, with robust biocontainment and mechanical reinforcement. Spontaneous enrichment of tyrosine-derived red pigments in the supernatant showcases the effect of confinement in a complex biochemical pathway. This work establishes a platform for encoding complex, engineered, and evolved functions of Gram-negative bacteria into synthetic materials, enabling the development of a wide range of material-based bioreactors.