Carboxylic mannan-coated iron oxide nanoparticles targeted to immune cells for lymph node-specific MRI in vivo

► Synthesis of CM-SPION for targeting APCs including macrophages. ► The interaction between the mannose ligand tethered on CM-SPION and mannose receptors on APCs. ► The in vitro and in vivo toxicities of CM-SPION were evaluated. ► The in vivo uptake of CM-SPION in LNs was tracked by MRI after subcutaneous injection in a rat model. ► Pre-dominant accumulation of CM-SPION in the popliteal LN.