活性氧信号转导在生物体内的生理和病理活动中起了重要的调节作用。胞内活性氧氧化蛋白质巯基（RSH）侧链生成蛋白质次磺酸 (RSOH)是该过程中的关键步骤之一。蛋白质次磺酸的快速、原位、动态检测对活性氧信号转导及活性氧相关疾病研究具有重要意义，但鲜有报导。“Turn-on”型荧光探针分子可与被测物作用，致使荧光由“off”转为“on”，实现对被测物的快速、无伤检测，已被广泛用于细胞内活性分子的快速、原位、实时检测。本项目将基于次磺酸的亲核性，研究次磺酸与张力环炔及其相关的串联反应，设计并合成次磺酸检测的“turn-on”型荧光探针分子，对其进行一系列的体外测试与评估，初步探索其在生物样品如细胞成像中的应用。因胞内次磺酸主要以蛋白质次磺酸形式存在，故申请者认为可通过本项目的研究实现胞内蛋白质次磺酸化的原位、实时、动态检测，为活性氧信号转导研究以及相关疾病研究诊断提供有力的工具。

ROS(Reactive oxygen species) signaling acts as an important regulator of physiological and pathophysiological outcomes and is thus high related to a serials of disease like cardiovascular disease, human degenerative diseases, hearing impairment via cochlear damage, congenital deafness , cancers, Amyotrophic lateral sclerosis (ALS) and so on. The formation of protein sulfenic acids (RSOH) through the oxidation of protein (RSH) by ROS was thought to be a key step in this process. Because the ROS signaling are complicate, dynamic biological activities, the fast, in situ and real-time detection of sulfenic acid is very important and even crucial to the research of redox signaling processes and the pathological study of related diseases. However, as we know, there is seldom such kind of assays. As the name suggests, the “turn-on” fluorescent probes can be turned on by reacting with analyte and have been employed for rapid and real-time detection of a serials of intracellular biological species like hydrogen sulfide, biothiols and so on. In this project, we will try to develop "turn-on" fluorescent probes for fast, in situ detection of intracellular sulfenic acid. The sulfenic acid is nucleophilic, and thus we will study its’ reactions towards strained cycloalkyne and their related tandem reactions, design and synthesize fluorescent probes for sulfenic acid, and test their applications in real biological samples like cell imagings. Because the intracellular sulfenic acids mainly exist in the form of protein bounded sulfenic acids, it is possible for us to use these probes to study the dynamic protein sulfenylation. The results of this project should be helpful for reactive oxygen species signaling study and related diseases diagnosis.