dendritic cell (DC)-specific intracellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) is a receptor found on DCs that recognizes antigens bearing mannose-rich or fucosylated glycans, including Lewis X (Le(X)). Here, we report the fabrication of magnetic nanoparticles coated with multivalent Le(X) glycans using Cu (I)-catalyzed azide-alkyne cycloaddition. The resulting nanoparticles are selective and biocompatible, serving as a highly efficient tool for DC detection and enrichment.