Regolith-supported biofabrication: 3D bioprinting of living, photosynthetically active structures using Lunar and Martian regolith simulants.

Abstract

Bioprinting, a technology with the potential to support long-term space missions, offers medical solutions for human settlements on the Moon and Mars. Moreover, 'green bioprinting' presents a promising approach to address terrestrial environmental challenges. Effective and cost-efficient implementation of this technology beyond the Earth requires leveraging<i>in situ</i>resources on celestial bodies. Consequently, this study examines the integration of Lunar and Martian regolith into bioprintable hydrogels as mechanically stabilizing and protective components as well as nutrient sources. Hydrogel blends composed of alginate and methylcellulose were supplemented with regolith simulants. Rheological characterization revealed maintenance of shear thinning and shear recovery properties, ensuring optimal printability. In regards to cultivation of microalgae, the ion release/uptake of the regolith simulants in culture medium was investigated, indicating that regolith has potential to serve as nutrient source. The microalga<i>Chlorella vulgaris</i>and bacteria<i>Buttiauxella sp</i>. MASE-IM-9 and<i>Salinisphaera shabanensis</i>were bioprinted in regolith-based inks. Results demonstrate that the microalgae maintained their photosynthetic efficiency in regolith-containing bioinks during cultivation, exhibiting high viability and growth. The bacteria exhibited an enhanced resistance to desiccation as well as temperature and radiation stress when regolith simulants were present in the hydrogels. This study confirms the feasibility of employing Lunar and Martian regolith simulants in bioinks for green bioprinting and bacterial bioprinting. Such an approach could minimize the volume of stored printing materials and culture media, optimizing rocket transport capacity.