A spatiotemporal probiotic spore-loaded oxygen generator Resumes gut microbiome balance and Improves hypoxia for treating viral pneumonia

In the present work, a smart and living biosystem with the integration of an oxygen generator and probiotic spores was developed, which was demonstrated to reverse gut dysbiosis, relieve intestinal hypoxia and resume immune homeostasis, thereby substantially alleviating the symptoms of viral pneumonia. • The oxygen generator was developed by encapsulating probiotic spores with PCS nanocoating and chelating them with CaO₂ NPs. • The oxygen generator overcame two barriers to enhance oxygen levels within IECs due to its spatiotemporal characteristics. • The oxygen generator maintained intestinal balance and protected against viral pneumonia via the gut-lung axis. Although evidence indicates that the incidence of viral pneumonia is causally associated with disturbances in the microbiome and hypoxic status in the gut, there is currently no effective strategy for the co-delivery of probiotics and oxygen through oral administration. We therefore created a spatiotemporal biosystem by preparing Bacillus coagulans (BC) probiotic spores, coating them with a polydopamine/chitosan (PCS) nanocoating, and conjugating them with CaO 2 nanoparticles. CaO 2 @PCS@BC spore rapidly diffused across the mucus layer spatially while released oxygen followed by bacterial proliferation temporally, thereby significantly enhancing the oxygen levels within intestinal epithelial cells by effectively overcoming the barriers posed by mucus layer and oxygen gradient. In a mouse model of H1N1 infection, we demonstrated that oral CaO 2 @PCS@BC spore treatment reversed gut dysbiosis, alleviated intestinal hypoxia, improved metabolism, restored immune balance, and mitigated symptoms of viral pneumonia. Finally, CaO 2 @PCS@BC spore facilitated spatial recovery and preserved the anaerobic environment of the gut lumen, suggesting significant biosafety. In conlusion, we have developed a spatiotemporal biosystem that effectively co-delivers probiotics and oxygen to mitigate intestinal dysbiosis in the treatment of viral pneumonia through the gut-lung axis.