Dual Switchable CRET-Induced Luminescence of CdSe/ZnS Quantum Dots (QDs) by the Hemin/G-Quadruplex-Bridged Aggregation and Deaggregation of Two-Sized QDs

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• 作者：Lianzhe Hu ; Xiaoqing Liu ; Alessandro Cecconello ; Itamar Willner
• 刊名：Nano Letters
• 出版年：2014
• 出版时间：October 8, 2014
• 年：2014
• 卷：14
• 期：10
• 页码：6030-6035
• 全文大小：367K
• ISSN：1530-6992

文摘

The hemin/G-quadruplex-catalyzed generation of chemiluminescence through the oxidation of luminol by H₂O₂ stimulates the chemiluminescence resonance energy transfer (CRET) to CdSe/ZnS quantum dots (QDs), resulting in the luminescence of the QDs. By the cyclic K⁺-ion-induced formation of the hemin/G-quadruplex linked to the QDs, and the separation of the G-quadruplex in the presence of 18-crown-6-ether, the ON-OFF switchable CRET-induced luminescence of the QDs is demonstrated. QDs were modified with nucleic acids consisting of the G-quadruplex subunits sequences and of programmed domains that can be cross-linked through hybridization, using an auxiliary scaffold. In the presence of K⁺-ions, the QDs aggregate through the cooperative stabilization of K⁺-ion-stabilized G-quadruplex bridges and duplex domains between the auxiliary scaffold and the nucleic acids associated with the QDs. In the presence of 18-crown-6-ether, the K⁺-ions are eliminated from the G-quadruplex units, leading to the separation of the aggregated QDs. By the cyclic treatment of the QDs with K⁺-ions/18-crown-6-ether, the reversible aggregation/deaggregation of the QDs is demonstrated. The incorporation of hemin into the K⁺-ion-stabilized G-quadruplex leads to the ON-OFF switchable CRET-stimulated luminescence of the QDs. By the mixing of appropriately modified two-sized QDs, emitting at 540 and 610 nm, the dual ON-OFF activation of the luminescence of the QDs is demonstrated.

Keywords:

Chemiluminescence; DNA; DNAzyme; switch; crown ether; fluorescence