Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
Methods Appl Fluoresc. 2019 Jul 30;7(4):042001. doi: 10.1088/2050-6120/ab2b2f.
Concentric Förster resonance energy transfer (cFRET) is an emerging concept for single-vector multiplexed bioanalysis and imaging. It features a network of competitive and sequential energy transfer pathways, which, to date, has been assembled with a central semiconductor quantum dot (QD) and biomolecular linkers to multiple copies of multiple types of concentrically-arranged fluorescent dyes. In this review, we provide a first-hand account of the concept and development of cFRET, starting from its place in the broader context of FRET probes and assemblies. Topics of discussion include materials for cFRET, with a focus on the enabling properties of QDs and the ideal properties of nominal acceptor dyes; characterization and analysis of cFRET configurations via photoluminescence intensity, emission ratio, lifetime, and photobleaching measurements; semi-empirical modeling to determine the rates and efficiencies of competitive and sequential FRET pathways from overall quenching efficiencies; and archetypical examples of cFRET configurations and their application in bioanalysis and imaging. Most of the latter examples demonstrate multiplexed detection of protease activity or nucleic acid targets. Examples of atypical and cFRET-like configurations are also discussed, including those that utilize time-gated FRET relays and charge-transfer quenching. We conclude with a perspective on challenges and directions for future research with cFRET. Although still emerging as a method, many exciting opportunities in bioanalysis, imaging, and beyond are envisioned for cFRET.
同心Förster 共振能量转移（cFRET）是一种新兴的单向量多重生物分析和成像概念。它具有一个竞争和顺序能量转移途径的网络，迄今为止，它已经与中心半导体量子点（QD）和生物分子接头组装在一起，形成了多个类型的同心排列荧光染料的多个拷贝。在这篇综述中，我们从 FRET 探针和组装的更广泛背景出发，提供了 cFRET 的概念和发展的第一手资料。讨论的主题包括 cFRET 的材料，重点是 QD 的使能特性和名义受体染料的理想特性；通过荧光强度、发射比、寿命和光漂白测量来表征和分析 cFRET 构型；半经验模型用于从整体猝灭效率确定竞争和顺序 FRET 途径的速率和效率；以及 cFRET 构型的典型示例及其在生物分析和成像中的应用。后者的大多数示例都演示了蛋白酶活性或核酸靶标的多重检测。还讨论了非典型和 cFRET 样构型的示例，包括利用时间门控 FRET 继电器和电荷转移猝灭的示例。我们以对 cFRET 未来研究的挑战和方向的展望结束。尽管作为一种方法仍在出现，但 cFRET 在生物分析、成像等领域以及其他领域都有许多令人兴奋的机会。
