Inhalable Capsular Polysaccharide‐Camouflaged Gallium‐Polyphenol Nanoparticles Enhance Lung Cancer Chemotherapy by Depleting Local Lung Microbiota

Abstract Local lung microbiota is closely associated with lung tumorigenesis and therapeutic response. It is found that lung commensal microbes induce chemoresistance in lung cancer by directly inactivating therapeutic drugs via biotransformation. Accordingly, an inhalable microbial capsular polysaccharide (CP)‐camouflaged gallium‐polyphenol metal–organic network (MON) is designed to eliminate lung microbiota and thereby abrogate microbe‐induced chemoresistance. As a substitute for iron uptake, Ga³⁺ released from MON acts as a “Trojan horse” to disrupt bacterial iron respiration, effectively inactivating multiple microbes. Moreover, CP cloaks endow MON with reduced immune clearance by masquerading as normal host‐tissue molecules, significantly increasing residence time in lung tissue for enhanced antimicrobial efficacy. In multiple lung cancer mice models, microbe‐induced drug degradation is remarkably inhibited when drugs are delivered by antimicrobial MON. Tumor growth is sufficiently suppressed and mouse survival is prolonged. The work develops a novel microbiota‐depleted nanostrategy to overcome chemoresistance in lung cancer by inhibiting local microbial inactivation of therapeutic drugs.