Silver nanoparticles outperform gold nanoparticles in radiosensitizing U251 cells in vitro and in an intracranial mouse model of glioma

Peidang Liu,^1,2 Haizhen Jin,¹ Zhirui Guo,³ Jun Ma,⁴ Jing Zhao,¹ Dongdong Li,¹ Hao Wu,² Ning Gu<sup>2

1</sup>School of Medicine, ²State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, ³The Second Affiliated Hospital of Nanjing Medical University, ⁴Traditional Chinese Medicine Hospital of Jiangsu Province, Nanjing, People’s Republic of China

Abstract: Radiotherapy performs an important function in the treatment of cancer, but resistance of tumor cells to radiation still remains a serious concern. More research on more effective radiosensitizers is urgently needed to overcome such resistance and thereby improve the treatment outcome. The goal of this study was to evaluate and compare the radiosensitizing efficacies of gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) on glioma at clinically relevant megavoltage energies. Both AuNPs and AgNPs potentiated the in vitro and in vivo antiglioma effects of radiation. AgNPs showed more powerful radiosensitizing ability than AuNPs at the same mass and molar concentrations, leading to a higher rate of apoptotic cell death. Furthermore, the combination of AgNPs with radiation significantly increased the levels of autophagy as compared with AuNPs plus radiation. These findings suggest the potential application of AgNPs as a highly effective nano-radiosensitizer for the treatment of glioma.

Keywords: gold nanoparticles, silver nanoparticles, radiosensitization, glioma, apoptosis, autophagy