Biocompatible, Hemocompatible and Antibacterial Acylated Dextran- g -polyisobutylene Graft Copolymers with Silver Nanoparticles

The novel amphiphilic acylated dextran-g-polyisobutylene (AcyDex-g-PIB) graft copolymers with different branch lengths (Mn,PIB, 2600–5800 g/mol) and grafting numbers (GN, 5–28 per 1000 Dex monosaccharide) were successfully synthesized via the nucleophilic substitution of the hydroxyl (―OH) side groups along AcyDex backbone by the living PIB-THF4+ chains prepared through cationic polymerization. The crystallization of AcyDex backbone in AcyDex-g-PIB graft copolymers was confined due to the presence of PIB branches and the morphology changed from short rod-like crystals to fragment-like crystals with increasing Mn,PIB and GN. The obvious microphase separation occurred due to the incompatibility between hard AcyDex backbone and soft PIB branches. AcyDex-g-PIB graft copolymers exhibit excellent biocompatibility towards HeLa cells and good hemocompatibility with red blood cells (RBCs), both of which increase with increasing GN. The increases of water contact angle and roughness on the surface of the graft copolymers with increasing Mn,PIB and GN manifest the anti-protein adsorption performance. The amphiphilic AcyDex-g-PIB graft copolymers could self-assemble in aqueous solution into nanospheres, which can be used as pH-sensitive drug carriers and can release 100% of the loaded drug within 72 h at pH=7.4. AcyDex-g-PIB graft copolymers bearing silver nanoparticles (Ag-NPs, 0.8 wt%–3.9 wt%, 4.5–9.5 nm) show good antibacterial properties. This kind of amphiphilic graft copolymer would have a promising prospect in biological and medical fields.