在生物系统中，细胞内pH（pHi）在调控各种生理活动中起着重要作用，包括酶活性、离子转运、细胞增殖、代谢和程序性细胞死亡等。监测活细胞内的pH对于研究吞噬作用、内吞作用和受体-配体内化等细胞事件非常关键。此外，某些细胞器如内泡体和溶酶体具有细胞间隔性的pH，对于维持蛋白质结构和功能的稳定性至关重要。功能失调和异常的pH调节可能导致癌症、阿尔茨海默病等终末疾病。因此，细胞内pH测量的准确性始终是首要任务，需要尖端的研究和分析。这类技术，如拉曼光谱和荧光成像，最好利用纳米技术，因为其具有非侵入性、精确性、可重复性和可再现性等显著优势。过去几十年来，已经有大量尝试设计和构建基于有机和无机材料的非侵入式纳米探针用于pHi感测。对于基于拉曼的技术，利用金/银/铜纳米颗粒等金属纳米结构来增强信号强度。至于基于荧光的研究，有机小分子（如染料）对pH呈现出更高的敏感性。然而，它们具有一些缺点，包括高光漂技术率和自发荧光背景信号。为此，已提出了一些替代性纳米材料，包括半导体量子点（QDs）、碳量子点、上转换纳米颗粒等。此外，荧光技术可以进行pH比值测量，从而提供可靠的校准曲线。本及时综述将对现有纳米探针的进展进行批判性考察。此外，基于我们的知识和现有研究成果，我们提供了一个简要的未来展望，可能推动pHi感测的最新方法的发展。版权©2023 Elsevier Inc.出版。

In the biological system, the intracellular pH (pHi) plays an important role in regulating diverse physiological activities, including enzymatic action, ion transport, cell proliferation, metabolism, and programmed cell death. The monitoring of pH inside living cells is also crucial for studying cellular events such as phagocytosis, endocytosis, and receptor-ligand internalization. Furthermore, some organelles, viz., endosomes and lysosomes, have intracompartmental pH, which is critical for maintaining the stability of protein structure and function. The dysfunction and abnormal pH regulation can result in terminal diseases such as cancer, Alzheimer, and so forth. Therefore, the accuracy of intracellular pH measurement is always the top priority and demands cutting-edge research and analysis. Such techniques, such as Raman spectroscopy and fluorescence imaging, preferably use nanotechnology due to their remarkable advantages, such as a non-invasive approach and providing accuracy, repeatability, and reproducibility. In the past decades, there have been numerous attempts to design and construct non-invasive organic and inorganic materials-based nanoprobes for pHi sensing. For Raman-based techniques, metal nanostructures such as Au/Ag/Cu nanoparticles are utilized to enhance the signal intensity. As for the fluorescence-based studies, the organic-based small molecules, such as dyes, show higher sensitivity toward pH. However, they possess several drawbacks, including high photobleaching rate, and autofluorescence background signals. To this end, there are alternative nanomaterials proposed, including semiconductor quantum dots (QDs), carbon QDs, upconversion nanoparticles, and so forth. Moreover, the fluorescence technique allows for ratiometric measurement of pHi, which as a result, offers a reliable calibration curve. This timely review will critically examine the current progression in the existing nanoprobes. In addition, based on our knowledge and available research findings, we provide a brief future outlook that may advance the state-of-the-art methodologies for pHi sensing.Copyright © 2023. Published by Elsevier Inc.