Apoptotic Body-Hitchhiked Manganese-Based Biomimetic Nanoprobe for Sensitive Magnetic Resonance Imaging of Bacteria Triggering Peritoneal Dialysis-Associated Peritonitis In Vivo

Peritoneal dialysis-associated peritonitis (PDAP), primarily caused by bacterial infections, is a severe complication and a major contributor to mortality in peritoneal dialysis patients. Early detection of bacterial infections and prompt therapeutic interventions are critical for effective PDAP management. Herein, we report the development of a novel apoptotic body (AB)-hitchhiked manganese-based T 1 -weighted magnetic resonance imaging (MRI) probe (PMA) for noninvasive and in situ bacterial detection in the abdominal cavity, offering a potential early warning system for PDAP. When administered to PDAP model mice, the PMA probes selectively accumulated in bacteria-infected regions via AB-mediated macrophage targeting. Subsequently, the PMA probes disintegrated in the acidic microenvironment of bacterial infection, which resulted in the MRI signal ON, therefore imaging the bacterial infection in vivo accurately. Remarkably, due to the protein-assisted T 1 -weighted signal amplification, the PMA probe-based MRI strategy detected bacterial loads in the abdominal cavity approximately 10 times lower than those identified by biochemical analysis for PDAP diagnosis. This approach achieves sensitive bacterial detection, holding great potential for the early diagnosis of PDAP in clinical practice in the future.