Amphiphilic carboxylated cellulose-g-poly(l-lactide) copolymer nanoparticles for oleanolic acid delivery

•Carboxylated cellulose-g-poly(l-lactide) copolymers were synthesized.•The amphiphilic copolymers improved the organic solubility of CCNs.•The copolymers were self-assembled into nanoparticles for oleanolic acid delivery.•The nanoparticles improved the drug solubility and prolonged the drug release.•The nanoparticles maintained the cell inhibition and enhanced antitumor efficiency. Carboxylated cellulose nanocrystals (CCNs), as one of nanocellulose are promising hydrophilic biomass materials for drug delivery. In this work, a series of amphiphilic carboxylated cellulose-graft-Poly(L-lactide) (CC-g-PLLA) copolymers were synthesized via ring-opening polymerization (ROP) method. The copolymers were characterized by 1H-NMR, FT-IR, WXRD and TGA, and their solubility in organic solvents was improved. Then, these amphiphilic copolymers were self-assembled into nanoparticles for delivery of anticancer drug oleanolic acid (OA). The copolymer (DSPLLA 2.03) nanoparticles displayed the smallest size (196.82 ± 9.14 nm) and the highest drug loading efficiency (24.76 ± 0.58%). The nanoparticles exhibited a spherical shape, well water solubility of OA (16.9 mg/mL) and a prolonged drug release (120 h). In vitro and In vivo study indicated that the nanoparticles maintained cytotoxicity to 4T1 cells and MCF-7 cells and displayed high antitumor efficiency. The amphiphilic CC-g-PLLA copolymer nanoparticles provide a novel platform for drug delivery.