题目：Size Effect of TiO2 Nanoparticles as Food Additive and Potential Toxicity
作者：Naiyan Lu, Zhe Chen, Jiaoyang Song, Yuyan Weng, Guofeng Yang, Qingrun Liu, Kai Yang, Xuemei Lu*, Yu Liu*
1 State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, Jiangsu, China
2 The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, Jiangnan University, 214122 Wuxi, Jiangsu, China
3 Wenzheng College of Soochow University, 215006 Suzhou, People’s Republic of China
4 Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, 215006 Suzhou, People’s Republic of China
5 Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
Titanium dioxide (TiO2), as a representative of metallic oxides, is widely used as food additive to serve as coloring or antibacterial packaging fortifier. However, in recent years, the potential hazards of nano-sized TiO2 food additives to human beings is still in doubt. In this work, we systematically studied the interactions between three sizes of TiO2 particles and the cell membrane systems with confocal laser scanning microscopy. We used both giant unilamellar vesicles and human colon cancer cells to mimic actual cell membrane systems. The results demonstrate the strong effect of particle size on membrane disruption and leakage behaviors. Among the three sizes of TiO2 nanoparticles (NPs) used in this work, the TiO2 NPs with the size of 110-300 nm are safe. In contrast, NPs with the size of 10-30 nm and 50-100 nm will cause the rupture and leakage of cell membranes. These indicates that the cytotoxicity of nano-sized TiO2 particles increases with the decrease of particle sizes. In addition, it is found that the size effect of TiO2 particles further depends on the membrane charge state. Simulations were also introduced to understand the results. This study would provide a theoretical basis for the production designing and safety standard of metallic oxide food additives.