Two-Photon Ratiometric Fluorescent Sensor Based on Specific Biomolecular Recognition for Selective and Sensitive Detection of Copper Ions in Live Cells

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• 作者：Yan Fu ; Changqin Ding ; Anwei Zhu ; Zifeng Deng ; Yang Tian ; Ming Jin
• 刊名：Analytical Chemistry
• 出版年：2013
• 出版时间：December 17, 2013
• 年：2013
• 卷：85
• 期：24
• 页码：11936-11943
• 全文大小：414K
• 年卷期：v.85,no.24(December 17, 2013)
• ISSN：1520-6882

文摘

In this work, we develop a ratiometric two-photon fluorescent probe, ATD@QD-E₂Zn₂SOD (ATD = amino triphenylamine dendron, QD = CdSe/ZnSe quantum dot, E₂Zn₂SOD = Cu-free derivative of bovine liver copper鈥搝inc superoxide dismutase), for imaging and sensing the changes of intracellular Cu²⁺ level with clear red-to-yellow color change based on specific biomolecular recognition of E₂Zn₂SOD for Cu²⁺ ion. The inorganic鈥搊rganic nanohybrided fluorescent probe features two independent emission peaks located at 515 nm for ATD and 650 nm for QDs, respectively, under two-photon excitation at 800 nm. Upon addition of Cu²⁺ ions, the red fluorescence of QDs drastically quenches, while the green emission from ATD stays constant and serves as a reference signal, thus resulting in the ratiometric detection of Cu²⁺ with high accuracy by two-photon microscopy (TPM). The present probe shows high sensivity, broad linear range (10^鈥?鈥?0^鈥? M), low detection limit down to 10 nM, and excellent selectivity over other metal ions, amino acids, and other biological species. Meanwhile, a QD-based inorganic-organic probe demonstrates long-term photostability, good cell-permeability, and low cytotoxicity. As a result, the present probe can visualize Cu²⁺ changes in live cells by TPM. To the best of our knowledge, this is the first report for the development of a QD-based two-photon ratiometric fluorescence probe suitable for detection of Cu²⁺ in live cells.