New bio-renewable polyester with rich side amino groups from L-lysine via controlled ring-opening polymerization

Lysine, a renewable resource from biomass fermentation, was simply converted to its corresponding α-hydroxyl acids and then cyclized to give the pure O-carboxyanhydride (OCA) monomer. Ring-opening polymerization of the resulting monomer was carried out using dimethylaminopyridine (DMAP) as a catalyst in CH2Cl2 at room temperature, and gave well-defined lysine-derived polyesters bearing pendant carbobenzyloxy (Cbz)-protected amino groups with number average molecular weight of up to 45 kg mol−1 in narrow polydispersity. 1H NMR, GPC, and MALDI-TOF MS measurements of the products clearly indicated the controlled/living character of the polymerization. Moreover, amino-functionalized polyesters were readily prepared by the removal of the Cbz protecting group, and the integrity of the polyester backbone was confirmed by 1H NMR. These amino-functionalized polyesters showed a tunable glass transition temperature and exhibited excellent cell compatibility, suggesting their potential to be used as novel materials in biomedical applications.