Abstract: BACKGROUND: Curcumin can inhibit the proliferation of human retinal pigment epithelial cells and anti-angiogenesis and can play an important role in the prevention and treatment of fundus neovascularization. However, its water solubility is poor and its half-life in the body is short. It requires long-term and multiple injections. Therefore, the development of a new dosage form of curcumin has an important clinical significance. 
OBJECTIVE: To study the synthesis of deoxycholic acid group grafted chitosan derivatives loaded curcumin nanoparticles and the effect of curcumin nanoparticles on the proliferation of human retinal pigment epithelial cells. 
METHODS: Chitosan-deoxycholic acid nanoparticles were prepared, and then curcumin/chitosan-deoxycholic acid nanoparticles were prepared to detect the drug loading, loading efficiency and in vitro drug release performance of curcumin/chitosan-deoxycholic acid nanoparticles. Human retinal pigment epithelial cells were co-cultured with curcumin (5, 10, 20, 40 mg/L), chitosan-deoxycholic acid nanoparticles (5, 10, 20, 40 mg/L), and curcumin/chitosan-deoxycholic acid nanoparticles (5, 10, 20, 40 mg/L). Cell proliferation was detected by the CCK-8 assay. 
RESULTS AND CONCLUSION: (1) The drug loading and loading efficiency of curcumin/chitosan-deoxycholic acid nanoparticles were 27.5% and 55%, respectively. Within the first 10 hours in vitro, the nanoparticles had a drug burst phenomenon, slowly released and then reached a balance until 96 hours later, and the cumulative amount of drug release was 31.6%. (2) The chitosan-deoxycholic acid nanoparticles of different mass concentrations had no significant effect on the proliferation of human retinal pigment epithelial cells after 24 and 48 hours of culture. (3) The curcumin of different mass concentrations and curcumin/chitosan-deoxycholic acid nanoparticles could suppress the proliferation of human retinal pigment epithelial cells in time- and mass-concentration-dependent manners. At the same mass concentration, the inhibition rate of cell proliferation of curcumin/chitosan-deoxycholic acid nanoparticles at 1-4 days of culture was lower than that of the curcumin group (P < 0.05). There was no significant difference in the inhibition rate of cell proliferation between the two groups cultured for 5 and 6 days (P > 0.05). (4) The results show that the curcumin-loaded chitosan-deoxycholic acid nanoparticles have an inhibitory effect on human retinal pigment epithelial cells, and the nanoparticles did not reduce the biological activity of the curcumin ingredients. 

Key words: nanoparticles, curcumin, retinal pigment epithelial cells, chitosan-deoxycholic acid, cell proliferation