A Neu5Acα2-3LacNAc trisaccharide (Neu5Acα2-3Galβ1-4GlcNAc) equipped with a biotin tag through a hydrophilic PEG3 spacer. The biotin moiety binds with high affinity to streptavidin and neutravidin, enabling straightforward immobilization on chips, in wells, or on other streptavidin/neutravidin-coated platforms. Neu5Acα2-3LacNAc is a ligand for selectins, Siglecs, and avian-type influenza hemagglutinin, which preferentially recognizes α2-3-linked sialic acids. This probe can be used as a soluble inhibitor or immobilized on plates or sensors to investigate binding. Neu5Acα2-3LacNAc is also a substrate for sialidases.