College of Chemistry and Chemical Engineering, Hubei University, Wuhan, 430062, China.
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education) College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China.
Small. 2019 Nov;15(48):e1901673. doi: 10.1002/smll.201901673. Epub 2019 Jun 3.
Intracellular pH is closely related with many biological processes, including cellular proliferation, apoptosis, endocytic processes, signal transduction, and enzymatic activity. The use of fluorescent probes has become an essential method for intracellular pH detection, but existing fluorescent probes have substantial limitations, such as requiring tedious synthetic preparation, suffering from an inappropriate response range and insufficiently long emission wavelength. In this work, a red emissive two-photon fluorescence probe based on carbon dots (pH-CDs) is fabricated using a facile one-pot hydrothermal method for the monitoring of intracellular pH. pH-CDs possess a variety of superior properties, including high selectivity, excellent photostability, and low cytotoxicity. Furthermore, they exhibit a pH-sensitive response in the range of 1.0-9.0 and a linear range of 3.5-6.5, which is desirable for tracking the pH value in living cells. It is demonstrated that the pH-dependent fluorescence signal is regulated via switching between aggregation and disaggregation of CDs. More importantly, pH-CDs can be successfully applied to sense and visualize pH fluctuation in cells, tissue, and zebrafish. These findings suggest that the as-prepared pH-CDs probe has significant potential for practical application in living systems.
细胞内 pH 值与许多生物过程密切相关，包括细胞增殖、细胞凋亡、内吞作用、信号转导和酶活性。荧光探针的使用已成为检测细胞内 pH 值的一种重要方法，但现有的荧光探针存在着很大的局限性，例如需要繁琐的合成准备，响应范围不合适，发射波长不够长。在这项工作中，我们使用一种简便的一步水热法制备了基于碳点的红色发射双光子荧光探针（pH-CDs），用于监测细胞内 pH 值。pH-CDs 具有多种优异的性质，包括高选择性、优异的光稳定性和低细胞毒性。此外，它们在 1.0-9.0 范围内呈现出 pH 敏感响应，线性范围为 3.5-6.5，这对于跟踪活细胞中的 pH 值是理想的。实验表明，通过碳点的聚集和解聚集来调节 pH 值依赖性荧光信号。更重要的是，pH-CDs 可以成功地用于检测和可视化细胞、组织和斑马鱼中的 pH 值波动。这些发现表明，所制备的 pH-CDs 探针在活体系统中具有重要的实际应用潜力。
