Abstract: Objective: To investigate the effects of ascorbic acid-polyethyleneimine carbon dots(CDs) on the proliferation, apoptosis and oxidative stress of the human osteosarcoma cell line MG63 cells, and to elucidate the biological characteristics of ascorbic acid-polyethyleneimine CDs. Methods: The ascorbic acid-polyethyleneimine CDs were synthesized with ascorbic acid and polyethyleneimine by microwave method. The proliferation rate of MG63 cells was detected by MTT method, and the percentages of MG63 cells at different cell cycles were detected by flow cytometry.The MG63 cells were divided into blank control group,negative control transfection group, GOLPH3-siRNA group, CDs group,negative control transfection+CDs group, GOLPH3-siRNA+CDs group. The expression levels of Golgi phosphorylation protein 3 (GOLPH3) gene in the MG63 cells in various groups were detected by PT-PCR method and the gene silencing efficiency was calculated; the apoptotic rates and reactive oxygen specie(ROS)levels in the MG63 cells in various groups were detected by flow cytometry. Results: Compared with blank control group, the proliferation rates of the MG63 cells were decreased with the increasing of CDs concentration; at 24 and 48 h, when the CDs concentration was more than 40 mg·L^-1, the proliferation rates of the MG63 cells were decreased significantly (P<0.05); at 72 h, when the CDs concentration was more than 20 mg·L^-1, the proliferation rates of the MG63 cells were decreased significantly (P<0.05). Compared with control group, the percentage of the MG63 cells at G₀/G₁ phase in CDs group was increased significantly(P<0.01), the percentage of the MG63 cells at S phase in CDs group was decreased significantly(P<0.01). The photoluminescence properties of CDs in the MG63 cells were seen under inverted fluorescence microscope; compared with non-CDs groups (blank control group, negative control transfection group, GOLPH3-siRNA group),the apoptotic rates of MG63 cells and the ROS levels in the MG63 cells in CDs groups(CDs group,negative control transfection+CDs group, GOLPH3-siRNA+CDs group)were increased(P<0.05). Conclusion: CDs have low toxicity and photoluminescence properties,which can arrest the cell cycle and promote the apoptosis and ROS production.GOLPH3 has the anti-apoptosis effect and inhibitory effect on the production of ROS to protect the survival of cells.

Key words: carbon dots, ascorbic acid, polyethyleneimine, Golgi stress, cell proliferation, apoptosis