Carbon-Dot and Quantum-Dot-Coated Dual-Emission Core–Satellite Silica Nanoparticles for Ratiometric Intracellular Cu2+ Imaging

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• 作者：Chenchen Zou ; Mohamed Frahat Foda ; Xuecai Tan ; Kang Shao ; Long Wu ; Zhicheng Lu ; Hagar Shendy Bahlol ; Heyou Han
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：July 19, 2016
• 年：2016
• 卷：88
• 期：14
• 页码：7395-7403
• 全文大小：667K
• 年卷期：0
• ISSN：1520-6882

文摘

Copper (Cu²⁺) is physiologically essential, but excessive Cu²⁺ may cause potential risk to plants and animals due to the bioaccumulative properties. Hence, sensitive recognition is crucial to avoid overintake of Cu²⁺, and visual recognition is more favored for practical application. In this work, a dual-emission ratiometric fluorescent nanoprobe was developed possessing the required intensity ratio, which can facilitate the sensitive identification of Cu²⁺ by the naked eye. The probe hybridizes two fluorescence nanodots (quantum dots (QDs) and carbon dots (CDs)). Although both of them can be viable fluorescence probes for metal ion detection, rarely research has coupled this two different kinds of fluorescence material in one nanosensor to fabricate a selectively ratiometric fluorescence probe for intracellular imaging. The red emitting CdTe/CdS QDs were capped around the silica microsphere to serve as the response signal label, and the blue-emitting CDs, which is insensitive to the analyte, were covalently attached to the QDs surface to act as the reference signal. This core–satellite hybrid sphere not only improves the stability and brightness of QDs significantly but also decreases the cytotoxicity toward HeLa cells tremendously. Moreover, the Cu²⁺ could quench the QDs emission effectively but have no ability for reduction of the CDs emission. Accordingly, a simple, efficient, and precise method for tracing Cu²⁺ was proposed. The increase of Cu²⁺ concentration in the series of 0–3 × 10^–6 M was in accordance with linearly decrease of the F₆₅₀/F₄₂₅ ratio. As for practical application, this nanosensor was utilized to the ratiometric fluorescence imaging of copper ions in HeLa cells.