State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, and Jiangsu Key Laboratory of Fine Chemicals and Functional Polymer Materials, Nanjing Tech University, Nanjing 210009, China.
Nanjing Environmental Monitoring Center, Nanjing 210013, China.
Nanoscale. 2020 Mar 5;12(9):5494-5500. doi: 10.1039/d0nr00381f.
Recently, widespread attention has been paid to red emissive carbon dots (CDs) which have desirable optical properties, low toxicity, and biocompatibility. Despite great efforts, the facile preparation of red dual-emissive CDs useful for ratiometric detection and bioimaging remains challenging. Here, we report a facile synthesis of red dual-emissive CDs and their potential for ratiometric fluorescence sensing and cellular imaging. Derived from the hydrothermal treatment of dicyandiamide and o-phenylenediamine in dilute sulfuric acid, the CDs are surface-tailored with nitrogen-, oxygen-, and sulfur-containing functional groups. The as-prepared CDs show various good features, including good water solubility, biocompatibility, excitation-independent dual-emission with two photoluminescence (PL) peaks centered at 630 and 680 nm, and an absolute quantum yield (QY) of 30.2% in water. The CDs exhibit a selective, sensitive, rapid, and stable ratiometric fluorescence response toward methyl blue, giving a linear relationship in the range of 0.5-300 μM with a correlation coefficient (R2) of 0.997. We also study ratiometric fluorescence sensing for the accurate detection of pH. Moreover, the CDs possess good cellular imaging ability, indicating their promising applicability for biomedical applications. These results pave a way toward the fabrication of red dual-emissive carbon-based nanomaterials useful for both ratiometric sensing and bioimaging.
最近，红色发射碳点（CDs）受到了广泛关注，因为它们具有理想的光学性质、低毒性和生物相容性。尽管已经做了很多努力，但仍然难以制备用于比率检测和生物成像的红色双发射 CDs。在这里，我们报告了一种简便的红色双发射 CDs 的合成方法，及其在比率荧光传感和细胞成像方面的潜在应用。通过在稀硫酸中对双氰胺和邻苯二胺进行水热处理，得到了表面经过氮、氧和硫等官能团修饰的 CDs。所制备的 CDs 具有许多良好的特性，包括良好的水溶性、生物相容性、激发独立的双发射特性，两个光致发光（PL）峰分别位于 630nm 和 680nm，在水中的绝对量子产率（QY）为 30.2%。CDs 对亚甲基蓝具有选择性、灵敏性、快速和稳定的比率荧光响应，在 0.5-300μM 范围内呈现出线性关系，相关系数（R2）为 0.997。我们还研究了比率荧光传感用于准确检测 pH 值。此外，CDs 还具有良好的细胞成像能力，表明其在生物医学应用中具有广阔的应用前景。这些结果为制备用于比率传感和生物成像的红色双发射碳基纳米材料铺平了道路。
