BACKGROUND: Cells in contact with nanomaterials can induce oxidative stress, allergic reactions, and then produce cytotoxicity and genotoxicity. Therefore, studies on nano toxicology have attracted more and more attention.OBJECTIVE: To comparatively evaluate the cytocompatibility of Pluronic (P85, F127, F87) tri-block copolymer nanoparticles modified with folic acid (FA) and polylactic acid (PLA).METHODS: Pluronic (P85, F127, F87) tri-block copolymer nanoparticles were modified with FA and PLA to synthesize a variety of amphiphilic block copolymers, including PLA-P85-PLA, FA-P85-PLA, PLA-F127-PLA, FA-F127-PLA,PLA-F87-PLA and FA-F87-PLA. The cytotoxicity of these synthesized nanoparticles was analyzed by cell morphology,cell metabolic activity and cell membrane effects in HepG-2 cells.RESULTS AND CONCLUSION: The relative growth rate of HepG-2 cells had no significant differences under 24-hour induction of various concentrations (5, 10, 20, 50, 100 mg/L) of unmodified P85, F127, and F87 nanoparticles (P > 0.05).The growth and proliferation of cells under the low concentrations (5, 10, 20, 50 mg/L) were enhanced. P85 NPs and F87 NPs could significantly inhibit cell viability at dose of 400 mg/L. In contrast, there were no significant differences towards P85, F127 and F87 nanoparticles (5, 10, 20, 50, 100, 200, 400 mg/L) modified with FA and PLA when compared with the control group (P > 0.05). These findings indicate that the modification of FA and PLA can improve the cytocompatibility of Pluronic (P85, F127, F87) tri-block copolymers, and therefore, PLA-Pluronic-PLA and FA-Pluronic-PLA nanoparticles are both good candidates for drug vectors.