Ultrasensitive detection of lung inflammation in male mice using immuno-magnetic particle imaging.

Timely and sensitive detection of inflammatory and infectious lung diseases remains a major clinical challenge. Current diagnostic approaches often identify pathology only at advanced stages, leaving gaps in acute triage, fibrotic activity assessment, transplant rejection monitoring and inflammation follow-up. Magnetic Particle Imaging (MPI) offers a sensitive, background-free, whole-body imaging modality without ionizing radiation. Here, we present immuno-Magnetic Particle Imaging (immuno-MPI) using micron-sized iron oxide particles targeted to VCAM-1, a key marker of endothelial inflammation. In three lung inflammation models in male mice, MPIO@αVCAM-1 generates high-contrast images within 3 minutes following intravenous injection at 1 mg/kg, with rapid accumulation at the inflamed endothelium and fast clearance of unbound particles. Predominantly confined to the vasculature, these particles selectively target VCAM-1 and discriminate inflamed from healthy lungs at doses as low as 0.18 mg/kg (7.5 µg iron). Specificity for VCAM-1 is confirmed by the absence of signal using control antibodies (MPIO@IgG) and competitive blocking with free αVCAM-1 antibodies. Overall, immuno-MPI provides a non-invasive approach that avoids ionizing radiation and supports pulmonary inflammation monitoring.