▎ 摘　　要

Graphene oxide (GO) nanosheet is a drug delivery system due to its structural properties, which can be augmented in presence of folic acid (FA). This study aimed to compare the efficacy of GO as a passive (GO/DOX) and active (GO/FA/DOX) forms for delivering doxorubicin (DOX). These two forms of conjugates were characterized before and after loading of DOX to confirm the conjugation as well as their properties including size and thermal stability. Using Ehrlich ascites carcinoma (EAC) cell line, the antitumor effect was evaluated by MTT assay in vitro and cell count; tumor cell cycle and apoptosis were evaluated by flow cytometry in vivo. The results showed that the loading percentages of DOX onto GO (GO/DOX) and GO/FA/DOX were 91% and 83%, respectively. TEM, FT-IR, and TGA confirmed the nano size, physical conjugation by shifted groups, and thermal stability. In vitro, the conjugates induced similar decrease of EAC cell viability, but still lower than those of free DOX. Treatment of EAC-bearing mice with GO/DOX or GO/FA/DOX forms induced significant decreases of the total numbers of EAC cells by 79% and 97%, respectively, as compared with free DOX (97%). DOX, GO/DOX, and GO/FA/DOX induced cell cycle arrest at G0, G1, and S phase, respectively. These conjugates also induced significant apoptosis with different profiles on viable, early, and late apoptotic EAC cells. In conclusion, loading DOX on GO nanosheet activated with FA can induce antitumor effect similar to those of free DOX but with different mechanisms.