Integrating L-Cys-AuNCs in ZIF-8 with Enhanced Fluorescence and Strengthened Stability for Sensitive Detection of Copper Ions

Gold nanoclusters (AuNCs) have been widely investigated because of their unique photoluminescence properties. However, the applications of AuNCs are limited by their poor stability and relatively low fluorescence. In the present work, we developed nanocomposites (L-Cys-AuNCs@ZIF-8) with high fluores...

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Main Authors: Ting Zhou, Luyao Zang, Xia Zhang, Xia Liu, Zijie Qu, Guodong Zhang, Xiufeng Wang, Fang Wang, Zhiqing Zhang
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/29/24/6011
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author Ting Zhou
Luyao Zang
Xia Zhang
Xia Liu
Zijie Qu
Guodong Zhang
Xiufeng Wang
Fang Wang
Zhiqing Zhang
author_facet Ting Zhou
Luyao Zang
Xia Zhang
Xia Liu
Zijie Qu
Guodong Zhang
Xiufeng Wang
Fang Wang
Zhiqing Zhang
author_sort Ting Zhou
collection DOAJ
description Gold nanoclusters (AuNCs) have been widely investigated because of their unique photoluminescence properties. However, the applications of AuNCs are limited by their poor stability and relatively low fluorescence. In the present work, we developed nanocomposites (L-Cys-AuNCs@ZIF-8) with high fluorescence and stability, which were constructed by encapsulating the water-dispersible L-Cys-AuNCs into a ZIF-8 via Zn<sup>2+</sup>-triggered growth strategy without high temperature and pressure. The maximum emission wavelength of the L-Cys-AuNCs@ZIF-8 composite was at 868 nm, and the fluorescence intensity of L-Cys-AuNCs@ZIF-8 was nearly nine-fold compared with L-Cys-AuNCs without the ZIF-8 package. The mechanism investigation by fluorescence spectroscopy and X-ray photoelectron spectroscopy showed that L-Cys-AuNCs@ZIF-8 impeded ligand rotation, induced energy dissipation, and diminished the self-quenching effect, attributing to the spatial distribution of L-Cys-AuNCs. Based on the high fluorescence efficiency of L-Cys-AuNCs@ZIF-8, a “signal off” detective platform was proposed with copper ions as a model analyte, achieving a sensitive detection limit of Cu<sup>2+</sup> at 16.7 nM. The quenching mechanism was confirmed, showing that the structure of the L-Cys-AuNCs@ZIF-8 nanocomposites was collapsed by the addition of Cu<sup>2+</sup>. Attributing to the strong adsorption ability between copper ions and pyridyl nitrogen, the as-prepared L-Cys-AuNCs@ZIF-8 was shown to accumulate Cu<sup>2+</sup>, and the Zn<sup>2+</sup> in ZIF-8 was replaced by Cu<sup>2+</sup>.
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spelling doaj-art-8324303bfdf149f6979e0ac5fc156a1a2025-08-20T02:43:45ZengMDPI AGMolecules1420-30492024-12-012924601110.3390/molecules29246011Integrating L-Cys-AuNCs in ZIF-8 with Enhanced Fluorescence and Strengthened Stability for Sensitive Detection of Copper IonsTing Zhou0Luyao Zang1Xia Zhang2Xia Liu3Zijie Qu4Guodong Zhang5Xiufeng Wang6Fang Wang7Zhiqing Zhang8Department of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaDepartment of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaDepartment of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaDepartment of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaDepartment of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaDepartment of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaDepartment of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaDepartment of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaDepartment of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, ChinaGold nanoclusters (AuNCs) have been widely investigated because of their unique photoluminescence properties. However, the applications of AuNCs are limited by their poor stability and relatively low fluorescence. In the present work, we developed nanocomposites (L-Cys-AuNCs@ZIF-8) with high fluorescence and stability, which were constructed by encapsulating the water-dispersible L-Cys-AuNCs into a ZIF-8 via Zn<sup>2+</sup>-triggered growth strategy without high temperature and pressure. The maximum emission wavelength of the L-Cys-AuNCs@ZIF-8 composite was at 868 nm, and the fluorescence intensity of L-Cys-AuNCs@ZIF-8 was nearly nine-fold compared with L-Cys-AuNCs without the ZIF-8 package. The mechanism investigation by fluorescence spectroscopy and X-ray photoelectron spectroscopy showed that L-Cys-AuNCs@ZIF-8 impeded ligand rotation, induced energy dissipation, and diminished the self-quenching effect, attributing to the spatial distribution of L-Cys-AuNCs. Based on the high fluorescence efficiency of L-Cys-AuNCs@ZIF-8, a “signal off” detective platform was proposed with copper ions as a model analyte, achieving a sensitive detection limit of Cu<sup>2+</sup> at 16.7 nM. The quenching mechanism was confirmed, showing that the structure of the L-Cys-AuNCs@ZIF-8 nanocomposites was collapsed by the addition of Cu<sup>2+</sup>. Attributing to the strong adsorption ability between copper ions and pyridyl nitrogen, the as-prepared L-Cys-AuNCs@ZIF-8 was shown to accumulate Cu<sup>2+</sup>, and the Zn<sup>2+</sup> in ZIF-8 was replaced by Cu<sup>2+</sup>.https://www.mdpi.com/1420-3049/29/24/6011fluorescenceL-Cys-AuNCs@ZIF-8Cu<sup>2+</sup> detectionquenching mechanism
spellingShingle Ting Zhou
Luyao Zang
Xia Zhang
Xia Liu
Zijie Qu
Guodong Zhang
Xiufeng Wang
Fang Wang
Zhiqing Zhang
Integrating L-Cys-AuNCs in ZIF-8 with Enhanced Fluorescence and Strengthened Stability for Sensitive Detection of Copper Ions
Molecules
fluorescence
L-Cys-AuNCs@ZIF-8
Cu<sup>2+</sup> detection
quenching mechanism
title Integrating L-Cys-AuNCs in ZIF-8 with Enhanced Fluorescence and Strengthened Stability for Sensitive Detection of Copper Ions
title_full Integrating L-Cys-AuNCs in ZIF-8 with Enhanced Fluorescence and Strengthened Stability for Sensitive Detection of Copper Ions
title_fullStr Integrating L-Cys-AuNCs in ZIF-8 with Enhanced Fluorescence and Strengthened Stability for Sensitive Detection of Copper Ions
title_full_unstemmed Integrating L-Cys-AuNCs in ZIF-8 with Enhanced Fluorescence and Strengthened Stability for Sensitive Detection of Copper Ions
title_short Integrating L-Cys-AuNCs in ZIF-8 with Enhanced Fluorescence and Strengthened Stability for Sensitive Detection of Copper Ions
title_sort integrating l cys auncs in zif 8 with enhanced fluorescence and strengthened stability for sensitive detection of copper ions
topic fluorescence
L-Cys-AuNCs@ZIF-8
Cu<sup>2+</sup> detection
quenching mechanism
url https://www.mdpi.com/1420-3049/29/24/6011
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