Bioprinted core-shell living material platform for spatially controlled encapsulation of Bacillus subtilis and sustained metabolite exchange

Antimicrobial resistance (AMR) represents an escalating global health crisis, demanding alternative strategies to reduce resistant pathogen burden across environments. Microbe-based biocontrol is promising, yet effectively deploying it in practical settings remains challenging. In this study, we present a 3D bioprinted core-shell construct featuring a polyethylene glycol diacrylate (PEGDA) shell with tunable nanoscale porosity, encapsulating germinable spores of the biocontrol agent Bacillus subtilis TH035. This configuration supports long-term spore viability while providing protection from common environmental stressors including UV-C irradiation, ethanol exposure, and desiccation over 4 weeks. The nanoporous PEGDA shell enables effective bacterial confinement while facilitating sufficient metabolite exchange for B. subtilis germination and growth, as well as suppression of methicillin-resistant Staphylococcus aureus (MRSA) growth by approximately one order of magnitude. This approach demonstrates the feasibility of embedding B. subtilis spores within engineered scaffolds for extended competitive functionality. The versatility and scalability of digital light processing (DLP) based bioprinting offers significant potential for tailored designs and high-throughput manufacturing. This proof-of-concept platform may find future applications in areas such as biomedical packaging, environmental sanitation, and built environment surface coatings, particularly in settings where intermittent moisture or nutrient availability can support spore germination and biocontrol activity.