Protons are highly related to cell viability during physiological and pathological processes. Developing new probes to monitor the pH variation could be extremely helpful to understand the viability of cells and the cell death study. Carbonized polymer dots (CPDs) are superior biocompatible and have been widely applied in bioimaging field. Herein, a new type of extreme-pH suitable CPDs was prepared from citric acid and o-phenylenediamine (CA/oPD-CPDs). Due to the co-existence of hydrophilic and hydrophobic groups, CA/oPD-CPDs tend to aggregate in neutral condition with a dramatic decrease of fluorescence, but disperse well in both acidic and alkaline conditions with brighter emission. This specialty enables them to selectively illuminate lysosomes in cells. Moreover, CA/oPD-CPDs in the cytoplasm could serve as a sustained probe to record intracellular pH variation during apoptosis. Furthermore, CA/oPD-CPDs present a continuous fluorescence increase upon 2-h laser irradiation in living cells, underscoring this imaging system for long-term biological recording.

质子与生理和病理过程中的细胞活力高度相关。开发新的探针来监测 pH 值变化对于了解细胞活力和细胞死亡研究非常有帮助。碳化聚合物点（CPD）具有优异的生物相容性，已广泛应用于生物成像领域。在此，由柠檬酸和邻苯二胺（CA/oPD-CPD）制备了一种新型的适合极端pH的CPD。由于亲水基团和疏水基团的共存，CA/oPD-CPDs在中性条件下容易聚集，荧光急剧下降，但在酸性和碱性条件下分散良好，发射更亮。这一特性使他们能够选择性地照亮细胞中的溶酶体。此外，细胞质中的CA/oPD-CPD可以作为持续探针来记录细胞凋亡过程中细胞内pH的变化。此外，CA/oPD-CPD 在活细胞中激光照射 2 小时后呈现连续荧光增加，强调了该成像系统用于长期生物记录。