Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada.
Photochem Photobiol Sci. 2013 Oct;12(10):1824-9. doi: 10.1039/c3pp50118c.
Optical imaging offers high sensitivity and portability at low cost. The design of an optimal "activatable" imaging agent could greatly decrease the background noise and increase specificity of the signal. Five different molecules have been used to quench basal fluorescence of an enzyme substrate labeled with Cy5, Cy5.5 or IR800 at a distance of 8 amino acids (32 Å): a 6 nm gold nanoparticle (NP), a 20 nm and a 30 nm iron oxide (FeO) NP, the black hole quencher BHQ-3 and the IRdye quencher QC-1. The quenching efficiencies were 99% for QC1-IR800, 98% for QC1-Cy5.5, 96% for 30 nm FeO NP-Cy5.5, 89% for BHQ3-Cy5, 84% for BHQ3-Cy5.5, 77-90% for 6 nm gold NP-Cy5.5, depending on the number of dyes around the NP, 79% for 20 nm FeO NP-Cy5.5 and 77% for Cy5.5-Cy5. Signal activation upon cleavage by the matrix metalloproteinase MMP9 was proportional to the quenching efficiencies, ranging from 3-fold with Cy5.5-Cy5 to 67-fold with QC1-IR800. This independent work reports on the properties of the dyes and quenchers explaining the superior performance of QC-1 and 30 nm FeO NPs.
光学成像是一种高灵敏度、低成本的方法。设计最佳的“激活型”成像剂可以大大降低背景噪声并提高信号的特异性。已经使用了五种不同的分子来猝灭标记有 Cy5、Cy5.5 或 IR800 的酶底物的基本荧光，距离为 8 个氨基酸（32Å）：6nm 金纳米粒子（NP）、20nm 和 30nm 氧化铁（FeO）NP、黑洞猝灭剂 BHQ-3 和 IRdye 猝灭剂 QC-1。QC1-IR800 的猝灭效率为 99%，QC1-Cy5.5 为 98%，30nm FeO NP-Cy5.5 为 96%，BHQ3-Cy5 为 89%，BHQ3-Cy5.5 为 84%，6nm 金 NP-Cy5.5 为 77-90%，这取决于 NP 周围染料的数量，20nm FeO NP-Cy5.5 为 79%，Cy5.5-Cy5 为 77%。基质金属蛋白酶 MMP9 切割后信号的激活与猝灭效率成正比，范围从 Cy5.5-Cy5 的 3 倍到 QC1-IR800 的 67 倍。这项独立的工作报告了染料和猝灭剂的性质，解释了 QC-1 和 30nm FeO NPs 的优异性能。
