On-demand controlled drug release holds great promise for cancer therapy. Light-degradable nanocarriers have gained increasing attention for designing controllable drug delivery systems owing to their spatiotemporally controllable properties. Herein, a highly luminescent and light-degradable nanocarrier is constructed by intercalating glutathione-capped gold nanoclusters (AuNCs) into zeolitic imidazolate framework-8 (ZIF-8) via competitive coordination assembly, named AuNC@ZIF-8, for light-triggered drug release. Glutathione-capped AuNCs and 2-methylimidazole (MIm) competitively coordinated with Zn²⁺ to form AuNC@ZIF-8 using a one step process in an aqueous solution. Specifically, the obtained AuNC@ZIF-8 has a high quantum yield of 52.96% and displays a distinctive property of photolysis. Competitive coordination interactions within AuNC@ZIF-8 were evidenced by X-ray diffraction and X-ray photoelectron spectroscopy, in which Zn²⁺ strongly coordinated with the N of MIm and weakly coordinated with the carboxyl/amino groups in the glutathione of AuNCs. Under light irradiation, the Au–S bond in AuNCs breaks, enhancing the coordination ability between carboxyl/amino groups and Zn²⁺. This collapses the crystal structure of AuNC@ZIF-8 and causes subsequent fluorescence quenching. Additionally, AuNC@ZIF-8 is successfully employed as a luminescent nanocarrier of anticancer drugs to form drug-AuNC@ZIF-8, in which three typical anticancer drugs are selected due to different coordination interactions. The obtained smart drug-AuNC@ZIF-8 can be effectively internalized into HeLa cells and degraded in response to blue light, with negligible dark cytotoxicity and high light cytotoxicity. This study highlights the crucial role of competitive coordination interactions in synthesizing functional materials with fluorescence efficiency and photolytic properties.

中文翻译：

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用于光响应药物释放的光可降解金纳米簇插层金属有机框架的竞争配位组装

按需控制药物释放为癌症治疗带来了巨大希望。光降解纳米载体由于其时空可控特性，在设计可控药物递送系统方面受到越来越多的关注。在此，通过竞争性配位组装将谷胱甘肽封端的金纳米团簇（AuNCs）插入沸石咪唑骨架8（ZIF-8）中，构建了一种高发光和可光降解的纳米载体，命名为AuNC@ZIF-8，用于光触发药物发布。谷胱甘肽封端的 AuNC 和 2-甲基咪唑 (MIm)在水溶液中通过一步法与 Zn ²⁺竞争性配位形成 AuNC@ZIF-8。具体而言，所获得的AuNC@ZIF-8具有52.96%的高量子产率，并表现出独特的光解特性。 X射线衍射和X射线光电子能谱证明了AuNC@ZIF-8内的竞争性配位相互作用，其中Zn ²⁺与MIm的N强配位，与AuNCs的谷胱甘肽中的羧基/氨基弱配位。在光照射下，AuNCs中的Au-S键断裂，增强了羧基/氨基与Zn ²⁺之间的配位能力。这破坏了 AuNC@ZIF-8 的晶体结构并导致随后的荧光猝灭。此外，AuNC@ZIF-8还成功用作抗癌药物的发光纳米载体，形成药物-AuNC@ZIF-8，其中由于不同的配位相互作用而选择了三种典型的抗癌药物。获得的智能药物AuNC@ZIF-8可以有效地内化到HeLa细胞中并响应蓝光而降解，具有可忽略的暗细胞毒性和高光细胞毒性。这项研究强调了竞争性配位相互作用在合成具有荧光效率和光解特性的功能材料中的关键作用。