Induction of cell death by Ta3N5 in the human cancer cell line

Photocatalysts are widely used in modern society, and their applications extend to medicine. Until now, ultraviolet light irradiation has been required for photocatalysis, but tantalum nitride (Ta3N5) has attracted attention as a next-generation photocatalyst because it produces reactive oxygen species (ROS) upon visible light irradiation. However, it has never been used in life science, and its toxicity was unknown. In the present study, we evaluated the cytotoxicity of Ta3N5 using U2OS cells in terms of light dose, irradiation time, Ta3N5 dope, and light wavelength. We also investigated the mode and mechanism of induced cell death. The results showed that cytotoxicity increased in a dose-, time-, and Ta3N5 dope-dependent manner, especially with blue light irradiation. On the other hand, high-dose light irradiation induced cytotoxicity with or without Ta3N5, indicating that green light and red light irradiation, which can selectively toxicize Ta3N5-added cells, may also be effective. We also showed that Ta3N5 induces secondary necrotic cell death in U2OS cells. These data indicate that Ta3N5 may be a photocatalyst that can be used in the medical and life science fields.光催化剂在现代社会中应用广泛，其应用范畴亦延伸至医学领域。此前光催化反应均需依托紫外光辐照，而氮化钽(Ta3N5)作为新一代光催化剂受到广泛关注，因其可在可见光辐照下产生活性氧(ROS)。然而此前其从未应用于生命科学领域，相关毒性也尚未明确。本研究以U2OS细胞为模型，从光辐照剂量、辐照时长、氮化钽掺杂量及光波长四个维度，评估了氮化钽的细胞毒性，并探究了其诱导细胞死亡的模式与机制。实验结果显示，细胞毒性呈剂量、时长及氮化钽掺杂量依赖式升高，尤以蓝光辐照组最为显著。另一方面，无论是否添加氮化钽，高剂量光辐照均可引发细胞毒性，这表明可选择性诱导添加氮化钽的细胞产生毒性的绿光与红光辐照，同样具备应用潜力。此外，本研究证实氮化钽可在U2OS细胞中诱导继发性坏死性细胞死亡。综上实验数据表明，氮化钽有望成为可应用于医学与生命科学领域的新型光催化剂。