Systematic Investigation of Metabolic Oligosaccharide Engineering Efficiency in Intestinal Cells Using a Dibenzocyclooctyne-Monosaccharide Conjugate.

Metabolic oligosaccharide engineering (MOE) of cells with synthetic monosaccharides can introduce functionality to the glycans of cell membranes. Unnatural sugars (e. g., peracetylated mannose-azide) can be expressed on the cell surface with the azide group in place. After MOE, the azide group can participate in a copper-free click reaction with an alkyne (e. g., dibenzocyclooctyne, DBCO) probe. This allows the metabolic fate of monosaccharides in cells to be understood. However, in a drug delivery context it is desirable to have azide groups on the probe (e. g. a drug delivery particle) and the alkyne (e. g. DBCO) on the cell surface. Consequently, the labelling efficiency of intestinal cell lines (Caco-2 and HT29-MTX-E12) treated with N-dibenzocyclooctyne-tetra-acetylmannosamine, and the concentration- and time-dependent labelling were determined. Furthermore, the labelling of mucus in HT29-MTX-E12 cells with DBCO was shown. This study highlights the potential for using MOE to target azide-functionalised probes to intestinal tissues for drug delivery applications.