Additive Manufacturing of Metabolically Active Living Materials with Physicochemical Biocontainment

Additive manufacturing (3D printing) of engineered living materials (ELMs) enables the spatial patterning of cells within three-dimensional (3D) polymer matrices. However, a critical barrier to deploying ELMs is the lack of universal and reliable strategies to contain cells within 3D printed matrices. While synthetic biology renders cell-specific containment, a materials-centric approach can provide a cell-agnostic biocontainment platform. Therefore, this study presents a hydrogel-based additive manufacturing strategy to fabricate ELMs with physicochemical biocontainment. The 3D printed ELMs are fabricated by copolymerizing Pluronic F127-bisurethane methacrylate (F127-BUM) with methacrylic acid (MAA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). Varying concentrations of these comonomers allow modulation of the ELM functionalities, namely, biocompatibility or antimicrobial properties. In particular, MAA-containing ELMs enable tunable biocontainment of the yeast Saccharomyces cerevisiae after immersion in 70 vol.% ethanol, leading to the formation of a time-dependent cell-free zone. The resulting yeast-laden ELMs enhance cell retention up to 300% (98 ± 12 h) and provide an average 38% fermentation increase compared to ELMs composed of only F127-BUM. In conclusion, this hydrogel-based spatiotemporal control strategy improves cell retention and metabolic activity performance in 3D-printed ELMs. These capabilities are promising for several applications, including 3D printed bioreactors and living therapeutic materials.