A Multifunctional Magnetic Microvesicle for Enhanced Chemodynamic Therapy and Immune Activation against Bacterial Infections.

How to make nanomaterials effectively target bacteria and enhance the antibacterial activation of immune cells is crucial for improving antibacterial efficacy. Herein, a magnetic extracellular vesicle that can not only activate macrophages in the infection microenvironment but also effectively kill bacteria is developed for enhancing antibacterial activation in vivo. The modification of d-galactose on the magnetic nanoparticles (GMNPs) and the loading of the GMNPs into macrophage-derived microvesicles (MVs) confer the resulting MVs@GMNPs with cascade-targeting capability, leading to high accumulation at the infection site. In the infectious microenvironment, the chemodynamic effect of the GMNPs triggers their rapid release from MVs. On one hand, the released GMNPs promote the polarization of macrophages toward the M1 phenotype, thereby enhancing antibacterial immune activation. On the other hand, GMNPs selectively bind to Pseudomonas aeruginosa (P. aeruginosa), enabling close contact with bacteria and effective chemodynamic therapy against infection. By combining chemical destruction with immune activation, MVs@GMNPs achieve efficient eradication of P. aeruginosa-induced subcutaneous abscesses with a bacterial inhibition rate of 99.8% in vivo.