Micellar mannose nanoparticles were constructed from poly{styrene-co-[(maleic anhydride)-alt-styrene]} with fluorophores or quenchers doped into the hydrophobic inner cores, allowing the direct monitoring of multivalent lectin-glycan interactions. The mannose-displaying nanoparticles bind Con A and sperm surface lectins with high affinity, suggesting their broad utility for modulating protein-carbohydrate interaction mediated cell surface biology.