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 ( M n,PIB , 2600–5800 g /mol) and grafting numbers ( G N , 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-THF 4 + 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 M n,PIB and G N . 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 G N . The increases of water contact angle and roughness on the surface of the graft copolymers with increasing M n,PIB and G N 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.