Glyco-β-cyclodextrin capped quantum dots: synthesis, cytotoxicity and optical detection of carbohydrate-protein interactions.

Highly fluorescent water soluble glyco-quantum dots were synthesized using a sonochemical procedure. The synthetic approach is based on specific host-guest interactions between β-cyclodextrin (β-CD) and trioctylphosphine oxide (TOPO) surfactant on quantum dots. The modified QDs were analyzed by a combination of FT-IR, (1)H-NOESY NMR spectroscopy and by TEM. The high sugar density on QDs resulted in selective colloidal aggregation with ConcanavalinA (ConA), Galanthus nivalis lectin (GNA) and Peanut agglutinin (PNA) lectins. Subsequently, in vitro studies indicated that β-CD modification of QDs enabled good cell viability of human hepatocellular carcinoma cell line (HepG2) cells. Finally, flow cytometry and confocal imaging studies revealed that βCDgal capped QDs undergo preferential binding with HepG2 cells. These results clearly demonstrate that β-CD capped QDs could be a promising candidate for further carbohydrate-based biomedical applications.