While the research on Engineered Living Materials (ELMs) is picking up speed, our cooperation project “ContainELMs” in the priority program 2451 of the German Research Foundation focuses on a critical, yet underexplored aspect: biocontainment. While previous studies on hybrid ELMs have demonstrated their general functionality, safe containment of living cells remains a challenge.

This project addresses this gap by designing core-shell fiber structures that provide genetic and physical biocontainment. While the Bioprogrammable Materials group of the INM at Saarbrücken will genetically modify bacteria to only survive in a specific microenvironment by engineering a genetic survival-switch, the Advanced Polymers and Biomaterials group of the IFG at KIT will design host structures based on core-shell-fiber scaffolds that maintain this specific microenvironment for extended times, with a possible application for bioremediation. To achieve this goal, 3D-electrohydrodynamic (EHD) Co-jetting will be used for the spatially controlled synthesis of multicompartment fiber scaffolds containing bacteria in combination with the Chemical Vapor Deposition (CVD) process, which can provide an additional external shell with custom-tailored surface properties.

The main challenges of this project can be summarized as diffusion and survival control. To ensure the survival of the cells during the production processes, the EHD jetting and CVD parameters need to be optimized and customized for the different bacteria strains. As for the biocontainment, the escape of the bacteria from the fibers is to be prevented, while the diffusion of nutrients and reactants into the fibers must be ensured. For long-term use, the specific microenvironment needs to be maintained prospectively by controlled diffusion of biofactors out of a core reservoir into the bacteria-containing compartment. These challenges can be addressed by optimizing polymers (-blends), their respective solvents, and hydrogels.