Synthesis and characterization of a novel glycoconjugated macromolecule

In this study, synthesis and characterization of a new galactosylated chitosan with high affinity to HepG2 (a liver cancer cell line) were reported. We designed the novel glycoconjugated macromolecule using chitosan to be grafted with branched galactose units. The branch-type of galactosylated chitosan was prepared by firstly introducing l-lysine spacer arms to chitosan, followed by covalent coupling of lactobionic acid with the lysine spacer to provide chitosan with multivalent galactose units. Essential properties of the branch-type of galactosylated chitosan measured from X-ray diffraction, mechanical and dynamic mechanical thermal analysis suggested that the introduction of branched galactosyl groups decreased the crystallinity and thermal stability of chitosan. Introducing galactosyl groups also resulted in a great enhancement of hydrophilicity, consequently increased the antibacterial capability of chitosan. The novel glycoconjugated chitosan possessed especially higher binding efficiency toward galectin-1 (Gal-1), a galactose-binding lectin, due to its multivalent galactose units. HepG2 cells were cultured onto the surface of the novel galactosylated chitosan films to examine the cell attachment and proliferation. Observation from the cell culture basically demonstrated that adjusting the length of spacer arms between the galactose units and macromolecular backbone led to a significant change in the HepG2 cells attachment and proliferation. The results suggest that the new chitosan derivative with branched galactose units may had a specific interaction with HepG2 cells via ligand-receptor recognition.