Development of Azaelectrocyclization-Based Labeling and Application to Noninvasive Imaging and Targeting Using N-Glycan Derivatives—In Pursuit of N-Glycan Functions on Proteins, Dendrimers, and Living Cells—

Abstract

The authors have developed the new positron emitting metal and fluorescence labeling protocol of ε-amino group of lysine through their rapid 6π-azaelectrocyclization. Using the same reaction, the small organic molecules could also be introduced on the amino groups of the living cell surface with simple operations under quite mild conditions, establishing the chemistry-based cell surface engineering with complex-type N-glycans. PET and the noninvasive fluorescence imaging of the N-glycoproteins and the world’s largest N-glycoclusters, mimicking the natural glyco-bioenvironment, for the first time visualized the differences in their in vivo dynamics and excretion pathway depending on the presence of the non-reducing end sialic acid as well as their linkages to the galactose residue. The authors also synthetically developed the artificial lymphocytes to target the tumors in living animals by introducing the complex-type N-glycans on the cell surfaces.