Therapeutic Nanoplatform Integrating Photothermal Effect and Silver Nanoparticles for the Treatment of Intracellular <i>Mycobacterium tuberculosis</i>

The global challenge of tuberculosis (TB), particularly in the context of rising drug resistance and intracellular bacterial persistence, highlights the need for innovative therapeutic strategies. In this study, we develop a multifunctional nanoplatform (CuS-Ag@FA) that integrates near-infrared (NIR)-responsive photothermal CuS, antimicrobial Ag nanoparticles (Ag NPs), and folate-receptor-mediated macrophage targeting for enhanced intracellular <i>Mycobacterium tuberculosis</i> (<i>M.tb</i>) clearance. Our work represents the first FA-functionalized CuS-Ag nanoplatform designed for dual-targeting of <i>M.tb</i>-infected macrophages and the first evaluation of this nanoplatform in an <i>M.tb</i>-infected animal model. FA functionalization markedly improves macrophage uptake, enabling precise intracellular delivery. Upon 808 nm irradiation, CuS-Ag@FA generates localized hyperthermia that synergizes with Ag NPs-induced oxidative and membrane-disruptive effects, resulting in potent intracellular bactericidal efficacy. Transcriptomic analysis reveals simultaneous inhibition of <i>M.tb</i> DNA replication, redox homeostasis, and metabolic pathways, supporting a multidimensional mechanism of action. In vivo studies confirm potent therapeutic efficacy, pulmonary accumulation, and favorable biosafety, establishing CuS-Ag@FA as a promising next-generation nanotherapeutic for combating drug-resistant and intracellular <i>M.tb</i>.