Intracellular pH plays a critical role in biological functions, and abnormal pH values are related to various diseases. Here, we report on an intracellular pH sensor AgInS₂ (AIS)/ZnS quantum dots (QDs) that show long fluorescence lifetimes of hundreds of nanoseconds and low toxicity. Fluorescence lifetime imaging microscopy (FLIM) combined with AIS/ZnS QDs is used for the imaging of live cells in different pH buffers and different cell lines. The FLIM images of AIS/ZnS QDs in live cells demonstrate different intracellular pH values in different regions, such as in lysosomes or cytoplasm. This method can also distinguish cancer cells from normal cells, and the fluorescence lifetime difference of the AIS/ZnS QDs between the two types of cells is 100 ± 7 ns. Most importantly, the exfoliated cervical cells from 20 patients are investigated using FLIM combined with AIS/ZnS QDs. The lifetime difference value between the normal and cervical cancer (CC) groups is 115 ± 9 ns, and the difference between the normal and the precancerous lesion group is 64 ± 9 ns. For the first time, the noninvasive method has been used for cervical cancer screening, and it has shown great improvement in sensitivity compared with a clinical conventional cytology examination.

细胞内pH值在生物学功能中起着至关重要的作用，pH值异常与各种疾病有关。在这里，我们报告了一种细胞内 pH 传感器 AgInS ₂(AIS)/ZnS 量子点 (QD)，具有数百纳秒的长荧光寿命和低毒性。荧光寿命成像显微镜 (FLIM) 与 AIS/ZnS 量子点相结合，用于对不同 pH 缓冲液和不同细胞系中的活细胞进行成像。活细胞中 AIS/ZnS 量子点的 FLIM 图像显示了不同区域（例如溶酶体或细胞质）中不同的细胞内 pH 值。该方法还可以区分癌细胞和正常细胞，两种细胞的AIS/ZnS量子点的荧光寿命差异为100±7 ns。最重要的是，使用 FLIM 结合 AIS/ZnS 量子点研究了来自 20 名患者的脱落宫颈细胞。正常组和宫颈癌 (CC) 组之间的寿命差异值为 115 ± 9 ns，正常与癌前病变组的差异为64±9ns。无创方法首次用于宫颈癌筛查，与临床常规细胞学检查相比，灵敏度有了很大提高。