Amphiphilic Graft Copolymers of Quaternized Alginate-g-Polytetrahydrofuran for Anti-protein Surfaces, Curcumin Carriers, and Antibacterial Materials

Amphiphilic quaternized alginate-g-polytetrahydrofuran (QA-g-PTHF) graft copolymers were successfully synthesized via nucleophilic substitution of living PTHF+ chains obtained via cationic ring-opening polymerization with the −OH side functional groups in QA. This unique graft copolymer exhibits low cytotoxicity and anti-protein adsorption. The QA-g-PTHF nanospheres (328 ± 21 nm) loaded with curcumin exhibit ninefold higher anticancer effect to HeLa cells than pure curcumin due to the synergistic roles from the graft copolymer. Both the interactions of cationic quaternary ammonium with the negatively charged HeLa cell surface and the hydrophobic PTHF branches with the hydrophobic cell membrane result in a great improvement in the entrance of nanospheres into HeLa cells and effective drug release therein. The QA-g-PTHF/Ag nanocomposites prepared in situ during the synthetic process demonstrate more than 98% killing efficiency for Escherichia coli and Staphylococcus aureus. To the best of our knowledge, this is the first example of an amphiphilic, anti-protein, and antibacterial QA-g-PTHF copolymer with low cytotoxicity for potential anticancer applications.