Living materials for gas therapy.

The clinical translation of gas therapy, which employs medical gases such as nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (HS), hydrogen (H), and sulfur dioxide (SO), is mainly limited by the absence of delivery systems that can provide precise spatiotemporal control in complex pathological environments. While conventional nanocarriers have improved in gas delivery, they often suffer from limited biocompatibility, poor targeting, and insufficient responsiveness. Recently, living materials emerged as a promising and innovative paradigm. Engineered from biological entities such as bacteria, cells, and algae, or their biomimetic derivatives, these materials inherently exhibit bioactive functions, including disease tropism, immunomodulation, and dynamic responsiveness to microenvironmental cues, thereby enabling intelligent gas generation and controlled release. This review systematically summarizes recent advances in living material-based gas therapy, with emphasis on classification according to biological origin and engineering design principles. We further discuss their mechanisms, including genetic programming for autonomous gas production and hybrid architectures for stimuli-responsive release, and highlight their therapeutic efficacy in cancer, inflammatory diseases, and tissue regeneration. Finally, we outline the major challenges in biosafety and scalability, and provide forward-looking perspectives on the integration of synthetic biology and multimodal therapeutic strategies to advance the field of precision gas medicine.