Environmental pH plays an irreplaceable role in both cellular processes and production, and anomalous pH changes within cells may lead to various diseases. To tackle this issue, we designed and synthesized the novel low-cytotoxicity fluorescent probe called . The probe incorporates 1,8-naphthalimide as the fluorescence emitter, 1-methylpiperazine as the pH-sensitive moiety, and utilizes 3-aminopropyltriethoxysilane to improve its biocompatibility. The fluorescence of inhibits the photoinduced electron transfer (PET) process with the protonation of 1-methylpiperazine, resulting in the enhancement of fluorescence intensity. Density functional theory calculations have also confirmed the fluorescence mechanism. The probe demonstrates high selectivity, photostability and recyclability. The hydrogel prepared by the probe can detect different concentrations of ammonia in the air. In addition, due to its low toxicity and good biocompatibility, this probe has been successfully employed to observe pH changes in living HeLa cells. Overall, the development of this probe offers significant potential in the field of pH sensing, allowing for precise monitoring of pH levels in both environmental and biological systems.

中文翻译：

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一种用于监测体内和体外pH值的新型低细胞毒性荧光探针

环境pH值在细胞过程和生产中起着不可替代的作用，细胞内pH值的异常变化可能导致各种疾病。为了解决这个问题，我们设计并合成了一种新型的低细胞毒性荧光探针，称为 。该探针采用 1,8-萘二甲酰亚胺作为荧光发射体，1-甲基哌嗪作为 pH 敏感部分，并利用 3-氨基丙基三乙氧基硅烷来提高其生物相容性。其荧光通过1-甲基哌嗪的质子化抑制光致电子转移（PET）过程，导致荧光强度增强。密度泛函理论计算也证实了荧光机制。该探针具有高选择性、光稳定性和可回收性。探针制备的水凝胶可以检测空气中不同浓度的氨。此外，由于其低毒性和良好的生物相容性，该探针已成功用于观察活体HeLa细胞的pH变化。总体而言，该探针的开发在 pH 传感领域具有巨大的潜力，可以精确监测环境和生物系统中的 pH 水平。