Acc Chem Res. 2015 May 19;48(5):1358-68. doi: 10.1021/acs.accounts.5b00009.
In an aerobic organism, reactive oxygen species (ROS) are an inevitable metabolic byproduct. Endogenously produced ROS have a significant role in physiological processes, but excess ROS can cause oxidative stress and can damage tissue. Cells possess elaborate mechanisms to regulate their internal redox status. The intracellular redox homeostasis plays an essential role in maintaining cellular function. However, moderate alterations in redox balance can accompany major transitions in a cell's life cycle. Because of the role of ROS in physiology and in pathology, researchers need new tools to study redox chemistry in biological systems.In recent years, researchers have made remarkable progress in developing new, highly sensitive and selective fluorescent probes that respond to redox changes, and in this Account we highlight related research, primarily from our own group. We present an overview of the design, photophysical properties, and fluorescence transduction mechanisms of reported molecules that probe redox changes. We have designed and synthesized a series of fluorescent probes for redox cycles in biological systems relying on the active center of glutathione peroxidase (GPx). We have also constructed probes based on the oxidation and reduction of hydroquinone and of 2,2,6,6-tetramethylpiperidinooxy (TEMPO). Most of these probes exhibit high sensitivity and good selectivity, absorb in the near-infrared, and respond rapidly. Such probes are useful for confocal fluorescence microscopy, a dynamic imaging technique that could allow researchers to observe biologically important ROS and antioxidants in real time. This technique and these probes provide potentially useful tools for exploring the generation, transport, physiological function, and pathogenic mechanisms of ROS and antioxidants.We also describe features that could improve the properties of redox-responsive fluorescent probes: greater photostability; rapid, dynamic, cyclic and ratiometric responses; and broader absorption in the near-IR region. In addition, fluorescent probes that include organochalcogens such as selenium and tellurium show promise for a new class of fluorescent redox probes that are both chemically stable and robustly reversible. However, further investigations of the chemical and fluorescence transduction mechanisms of selenium-based probes in response to ROS are needed.
在需氧生物中，活性氧（ROS）是一种不可避免的代谢副产物。内源性产生的 ROS 在生理过程中具有重要作用，但过量的 ROS 会导致氧化应激并损害组织。细胞具有精细的机制来调节其内部氧化还原状态。细胞内的氧化还原稳态对于维持细胞功能至关重要。然而，细胞生命周期中的重大转变可能伴随着氧化还原平衡的适度改变。由于 ROS 在生理学和病理学中的作用，研究人员需要新的工具来研究生物系统中的氧化还原化学。近年来，研究人员在开发新的、高度敏感和选择性的荧光探针以响应氧化还原变化方面取得了显著进展，在本综述中，我们重点介绍了相关研究，主要来自我们自己的小组。我们介绍了报道的用于生物系统氧化还原变化的分子的设计、光物理性质和荧光转导机制的概述。我们设计并合成了一系列基于谷胱甘肽过氧化物酶（GPx）活性中心的生物系统氧化还原循环的荧光探针。我们还构建了基于氢醌和 2,2,6,6-四甲基哌啶氧自由基（TEMPO）的氧化还原的探针。这些探针大多数具有高灵敏度和良好的选择性，在近红外光区吸收，并能快速响应。这些探针对于共聚焦荧光显微镜非常有用，共聚焦荧光显微镜是一种动态成像技术，可以让研究人员实时观察生物上重要的 ROS 和抗氧化剂。该技术和这些探针为探索 ROS 和抗氧化剂的产生、运输、生理功能和致病机制提供了潜在的有用工具。我们还描述了可以改善氧化还原响应荧光探针性能的特征：更高的光稳定性；快速、动态、循环和比率响应；以及在近红外区域更宽的吸收。此外，包含有机碲和硒等有机硫属元素的荧光探针有望成为一类新的化学稳定且具有强可逆性的荧光氧化还原探针。然而，需要进一步研究基于硒的探针在响应 ROS 时的化学和荧光转导机制。
