Department of Chemistry, National University of Singapore, Singapore 117543.
J Am Chem Soc. 2011 Aug 10;133(31):12009-20. doi: 10.1021/ja200808y. Epub 2011 Jul 15.
Fluorescence imaging provides an indispensable way to locate and monitor biological targets within complex and dynamic intracellular environments. Of the various imaging agents currently available, small molecule-based probes provide a powerful tool for live cell imaging, primarily due to their desirable properties, including cell permeability (as a result of their smaller sizes), chemical tractability (e.g., different molecular structures/designs can be installed), and amenability to imaging a wide variety of biological events. With a few exceptions, most existing small molecule probes are however not suitable for in vivo bioimaging experiments in which high-resolution studies of enzyme activity and localization are necessary. In this article, we reported a new class of fluorescently Quenched Activity-Based Probes (qABPs) which are highly modular, and can sensitively image (through multiple enzyme turnovers leading to fluorescence signal amplification) different types of enzyme activities in live mammalian cells with good spatial and temporal resolution. We have also incorporated two-photon dyes into our modular probe design, enabling for the first time activity-based, fluorogenic two-photon imaging of enzyme activities. This, hence, expands the repertoire of 'smart', responsive probes currently available for live cell bioimaging experiments.
荧光成像提供了一种不可或缺的方法，可以在复杂和动态的细胞内环境中定位和监测生物靶标。在目前可用的各种成像剂中，基于小分子的探针为活细胞成像提供了一种强大的工具，主要是因为它们具有理想的特性，包括细胞通透性（由于其较小的尺寸）、化学可处理性（例如，可以安装不同的分子结构/设计）以及适用于成像各种生物事件。然而，除了少数例外，大多数现有的小分子探针并不适合用于体内生物成像实验，因为在这些实验中需要对酶活性和定位进行高分辨率研究。在本文中，我们报道了一类新的荧光猝灭活性基探针 (qABPs)，它们具有高度的模块化，可以在活哺乳动物细胞中以高时空分辨率灵敏地成像（通过多次酶周转导致荧光信号放大）不同类型的酶活性。我们还将双光子染料纳入我们的模块化探针设计中，首次实现了基于活性的、荧光双光子酶活性成像。因此，这扩展了目前可用于活细胞生物成像实验的“智能”、响应性探针的范围。
