The transplantation of endothelial progenitor cells (EPCs) has been shown to reduce neointimal hyperplasia following arterial injury. However, the efficacy of this approach is hampered by limited homing of EPCs to the injury site. Additionally, the in vivo recruitment and metabolic activity of transplanted EPCs have not been continuously monitored.

EPCs were labeled with indocyanine green (ICG)-conjugated superparamagnetic iron oxide nanoparticles (SPIONs) and subjected to external magnetic field targeting to enhance their delivery to a carotid balloon injury (BI) model in Sprague–Dawley rats. Magnetic particle imaging (MPI)/ fluorescence imaging (FLI) multimodal in vivo imaging, 3D MPI/CT imaging and MPI/FLI ex vivo imaging was performed after injury. Carotid arteries were collected and analyzed for pathology and immunofluorescence staining. The paracrine effects were analyzed by enzyme-linked immunosorbent assay.

The application of a magnetic field significantly enhanced the localization and retention of SPIONs@PEG-ICG-EPCs at the site of arterial injury, as evidenced by both in vivo continuous monitoring and ex vivo by observation. This targeted delivery approach effectively inhibited neointimal hyperplasia and increased the presence of CD31-positive cells at the injury site. Moreover, serum levels of SDF-1α, VEGF, IGF-1, and TGF-β1 were significantly elevated, indicating enhanced paracrine activity.

Our findings demonstrate that external magnetic field-directed delivery of SPIONs@PEG-ICG-EPCs to areas of arterial injury can significantly enhance their therapeutic efficacy. This enhancement is likely mediated through increased paracrine signaling. These results underscore the potential of magnetically guided SPIONs@PEG-ICG-EPCs delivery as a promising strategy for treating arterial injuries.