Peroxynitrite and lysosomes are important biologically reactive oxygen species and subcellular organelles, respectively. The level of peroxynitrite and the value change of pH in lysosomes have a significant impact on living cells. Thus, the detection of peroxynitrite and lysosomal pH in live cells is very important. Herein, a novel probe (ONOO-LysopH) was developed, which not only can detect peroxynitrite in lysosomes, but also can be used to track the lysosomal pH changes. ONOO-LysopH is based on a new rhodamine derivate with near-infrared (NIR) emission and large Stokes shift. ONOO-LysopH is sensitive to acid and shows an instantaneous and reversible response of NIR emission around 686 nm with a pKa value of 5.41. ONOO-LysopH also exhibits a quick, sensitive, and selective response to peroxynitrite at physiological pH with a largely enhanced NIR fluorescence signal at 678 nm. The application of ONOO-LysopH to track lysosomal pH changes and image both endogenous and exogenous peroxynitrite in live cells was demonstrated. Thus, this work provided a potential multifunctional probe for peroxynitrite detection and lysosomal pH change tracking in live systems.

过氧亚硝酸盐和溶酶体分别是重要的生物活性氧和亚细胞器。溶酶体中过氧亚硝酸盐的水平和pH值的变化对活细胞有重大影响。因此，检测活细胞中过亚硝酸盐和溶酶体的pH非常重要。在本文中，开发了一种新型探针（ONOO-LysopH），其不仅可以检测溶酶体中的过氧亚硝酸盐，而且可以用于追踪溶酶体的pH变化。ONOO-LysopH基于具有近红外（NIR）发射和大斯托克斯位移的新型罗丹明衍生物。ONOO-LysopH对酸敏感，在686 nm附近显示NIR发射的瞬时和可逆响应，pKa值为5.41。ONOO-LysopH在生理pH值下，NPO也会对过氧亚硝酸盐表现出快速，敏感和选择性的响应，在678 nm处的NIR荧光信号大大增强。证明了ONOO-LysopH在追踪溶酶体pH变化并在活细胞中对内源性和外源性过氧亚硝酸盐成像的应用。因此，这项工作提供了一种潜在的多功能探针，用于在生活系统中检测过氧亚硝酸盐和溶酶体pH值变化。