Molecular Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory , Wright-Patterson AFB, Ohio 45433, United States.
ACS Appl Mater Interfaces. 2016 Aug 24;8(33):21221-7. doi: 10.1021/acsami.6b06624. Epub 2016 Aug 10.
To date, the directed in situ synthesis of fluorescent gold nanoclusters (AuNCs) has only been demonstrated in cancerous cells, with the theorized synthesis mechanism prohibiting AuNC formation in nontumorigenic cell lines. This limitation hinders potential biostabilized AuNC-based technology in healthy cells involving both chemical and mechanical analysis, such as the direct sensing of protein function and the elucidation of local mechanical environments. Thus, new synthesis strategies are required to expand the application space of AuNCs beyond cancer-focused cellular studies. In this contribution, we have developed the methodology and demonstrated the direct in situ synthesis of AuNCs in the nontumorigenic neuronal microglial line, C8B4. The as-synthesized AuNCs form in situ and are stabilized by cellular proteins. The clusters exhibit bright green fluorescence and demonstrate low (<10%) toxicity. Interestingly, elevated ROS levels were not required for the in situ formation of AuNCs, although intracellular reductants such as glutamate were required for the synthesis of AuNCs in C8B4 cells. To our knowledge, this is the first-ever demonstration of AuNC synthesis in nontumorigenic cells and, as such, it considerably expands the application space of biostabilized fluorescent AuNCs.
迄今为止，荧光金纳米簇（AuNCs）的定向原位合成仅在癌细胞中得到了证明，其理论合成机制禁止 AuNC 在非致瘤细胞系中形成。这种局限性阻碍了基于生物稳定 AuNC 的技术在健康细胞中的潜在应用，包括化学和机械分析，如直接检测蛋白质功能和阐明局部力学环境。因此，需要新的合成策略来扩大 AuNC 的应用空间，超越以癌症为重点的细胞研究。在本研究中，我们开发了一种方法，并在非致瘤神经元小胶质细胞系 C8B4 中直接原位合成了 AuNC。合成的 AuNC 原位形成并由细胞蛋白稳定。这些簇表现出明亮的绿色荧光，且毒性低（<10%）。有趣的是，虽然细胞内还原剂如谷氨酸对于 C8B4 细胞中 AuNC 的合成是必需的，但原位形成 AuNC 并不需要升高的 ROS 水平。据我们所知，这是首次在非致瘤细胞中证明 AuNC 合成，因此，它极大地扩展了生物稳定荧光 AuNC 的应用空间。
