Qiu Chunmin, Wu Guoqiang, Zhao Puying, Dai Junbiao, Luo Qian, Zhao Liqing, Mao Guobin, Ma Yingxin
College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China; Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China; School of Pharmacy, Faculty of Medicine, Macau University of Science and Technology, Macau SAR, China.
Anal Chim Acta. 2025 Feb 15;1339:343637. doi: 10.1016/j.aca.2025.343637. Epub 2025 Jan 9.
High-precision and broad-range pH detection is critical for health status assessment, such as signal transduction, enzyme activity, endocytosis, and cell proliferation and apoptosis. Although pH-responsive ratiometric fluorescent probes offer an effective pH monitoring strategy, their preparation often requires multi-step modification and decreases fluorescence efficiency and stability. Herein, we developed a simple method to prepare fluorescent Si dots with dual emission centers for high-precision and broad-range pH monitoring, and the detection of urease based on pH-responsive Si dots and pH monitoring in living cell was further explored.
The dual-emitting Si dots had two emission centers at 427 nm and 500 nm. The emission at 427 nm showed a fluorescence enhancement and effective quenching in the pH ranges of 3.0-10.0 and 10.0-12.0, respectively. While the emission at 500 nm increased gradually with increasing pH from 3.0 to 12.0. Two linear relationships were obtained between the synchronous fluorescence intensity ratio and pH in the ranges of 7.0-9.5 and 10.0-12.0 with a △pH of 0.1, indicating a broad detection range and high precision. Then the Si dots were used to detect urease activity via urea hydrolysis-mediated pH changes. A linear range of 1-80 U/L was established with a detection limit of 0.28 U/L. Furthermore, the Si dots were used for pH imaging in living HeLa cells. The cells changed from green to blue when the pH of HeLa cells increased from 6.0 to 10.0.
These findings collectively suggest that the intrinsic dual-emitting Si dots may offer a simple and versatile platform for developing pH-relevant biosensors and bioimaging applications. Additionally, this approach provides reliable methods for preparing intrinsic dual-emitting probe and constructing fluorescence ratiometrics, which widely used in health status assessment.
高精度和宽范围的pH检测对于健康状况评估至关重要，例如信号转导、酶活性、内吞作用以及细胞增殖和凋亡。尽管pH响应型比率荧光探针提供了一种有效的pH监测策略，但其制备通常需要多步修饰，并且会降低荧光效率和稳定性。在此，我们开发了一种简单的方法来制备具有双发射中心的荧光硅点，用于高精度和宽范围的pH监测，并进一步探索了基于pH响应型硅点的脲酶检测以及在活细胞中的pH监测。
双发射硅点在427nm和500nm处有两个发射中心。427nm处的发射在pH值为3.0 - 10.0和10.0 - 12.0范围内分别表现出荧光增强和有效猝灭。而500nm处的发射随着pH值从3.0增加到12.0逐渐增强。在7.0 - 9.5和10.0 - 12.0范围内，同步荧光强度比与pH之间获得了两个线性关系，ΔpH为0.1，表明检测范围宽且精度高。然后，利用硅点通过尿素水解介导的pH变化来检测脲酶活性。建立了1 - 80 U/L的线性范围，检测限为0.28 U/L。此外，硅点用于活的HeLa细胞中的pH成像。当HeLa细胞的pH值从6.0增加到10.0时，细胞从绿色变为蓝色。
这些发现共同表明，本征双发射硅点可能为开发与pH相关的生物传感器和生物成像应用提供一个简单且通用的平台。此外，这种方法为制备本征双发射探针和构建荧光比率法提供了可靠的方法，广泛应用于健康状况评估。
