Programmable Semi-Interpenetrating Living Materials With Robust Stability for Versatile Bioremediation and Biotherapeutics.

The practical application of engineered living materials (ELMs) is currently hindered by some critical challenges, such as streamlining fabrication processes and achieving long-term stability. Here, a semi-interpenetrating ELM was developed relying on thermosensitive self-assembly of hydroxybutyl chitosan (HBC) and spontaneous covalent protein interactions. This semi-interpenetrating network provided superior mechanical properties over HBC hydrogels. Furthermore, this material can be adapted for diverse scenarios based on engineered bacteria encapsulated, and its applications in biotherapy treatment and environmental remediation were validated. Compared to planktonic bacteria or enzymes, this ELM presented enhanced tolerance to harsh environments, including high temperatures, extreme pH values, high salinity, and digestive fluids, resulting in improved therapeutic efficacy with excellent biosafety in ulcerative colitis treatment and long-term degradation of the pollutant paraoxon. In summary, our material offers advantages including simple preparation, excellent mechanical properties, high stability, customizability, and biosafety, laying a foundation for the application of ELMs.