Nanopipette-assisted single cell metabolic glycan labeling.

Here, we report a single cell glycan labeling strategy by combining nanoscale intracellular glass electrodes with bioorthogonal reaction. With the tip diameter less than 100 nm, the nanopipette electrode can be spatially controlled to inject artificial monosaccharides into single living cells with minimal invasion. The injection process can be precisely regulated by electroosmotic flow inside the nanopipette, and fluorescence labeling of sialic acid at single cell level is achieved.