Glycosylation plays a key role in mediating molecular recognition,development,and cell signaling.The metabolic glycan labeling technique has recently emerged as an appealing approach for detecting and imaging glycans on live cells and within living animals.However,this technique lacks cell-type selectivity.Here,we present the development of a cell-specific metabolic glycan labeling strategy using azidosugars encapsulated in ligand-targeted liposomes.The ligands are designed to bind specific cell-surface receptors that are only expressed or up-regulated in target cells,which mediates the intracellular delivery of azidosugars.The delivered azidosugars are metabolically incorporated into cell-surface glycans,which are then imaged via a bioorthogonal reaction.