Utilizing the superoxide dismutase activity of ceria nanoparticles to endow poly-l-lactic acid bone implants with antitumor function

Currently, numerous bone tumor patients undergo tumor recurrence after surgical resection, which seriously affects their quality of life. In this study, the ceria (CeO₂) nanoparticle was added to Poly-L-Lactic Acid (PLLA) bone implants endowing the bone implant with antitumor function. The results showed that the reactive oxygen species increased in U2OS cells while it dropped in HEK293 cells as the CeO₂ content increased. Meanwhile, the PLLA-8CeO₂ showed a high cell inhibition rate of 53.66 % for U2OS cells and possessed a high cell viability of 76.96 ± 2.20 % for HEK293 cells, meaning that the implant could kill bone tumor cells meanwhile show good cytocompatibility for normal cells. These were mainly due to the fact that the CeO₂ nanoparticles acted as a superoxide dismutase in tumor cells reducing superoxide to hydrogen peroxide, inducing an increase in reactive oxygen species levels. The excess reactive oxygen species could result in tumor cell apoptosis by disrupting mitochondrial structure, oxidizing proteins, and promoting DNA denaturation. Moreover, the compressive strength of PLLA was improved by the CeO₂ addition due to its particle dispersion strengthening. Besides, the PLLA-CeO₂ had a faster degradation rate compared to PLLA. Overall, the PLLA-CeO₂ is a promising implant material for bone tumor treatment.