Engineered Living Materials for the Design and Fabrication of Functional Bioceramics

Abstract

Engineered Living Materials (ELMs) use living microbial cells as biofactories that can produce and assemble extracellular matrix (ECM) components into macroscopic structures that can be tailored to enhance the functional performance of macroscopic materials. These living materials can be programmed to respond to various environmental stimuli, sequester pollutants, and possess self-regenerative and self-healing capabilities. Given these advantages, autogenic ELMs have the potential to revolutionize the built environment. In ELMs, protein nanofibers serve as programmable structural scaffolds whose function and interaction with inorganic phases can be encoded directly by genetically engineering. Here, Escherichia coli is engineered to express functionalized curli fibers fused to Mms6, a protein that promotes the mineralization of magnetite (Fe₃O₄) and specifically binds to the mineral. The result is a bioceramic material produced at room temperature, therefore with significantly less energy than current methods. Additionally, the fibers' orientation is controlled using magnetic fields to create anisotropic materials with tunable mechanical properties. Furthermore, this method can be used to control electron transport within the material, showing potential for applications in electronics. To create multiple composite materials and explore the potential of using this platform to build on extraterrestrial soil, we further engineered these constructs to include R5 silica-binding peptide, together with Mms6, to enhance the ability to bind to Martian and lunar soil, as well as basalt, a silica-rich material already used in construction. By addressing material scarcity in extreme environments, we show how extraplanetary constraints can drive sustainable innovation on Earth