Cyanides have been recognized as one of the most toxic chemicals and are harmful to the environment and human beings. Herein, fluorescence resonance energy transfer (FRET)-based upconversion nanoprobes for cyanide anions have been designed and prepared by assembling Au nanoparticles (NPs) on core–shell-structured NaYF₄:Yb,Er@NaYF₄:Yb upconversion NPs (csUCNPs), where csUCNPs act as the energy donor and Au NPs act as the energy acceptor. The Au content was optimized in order to have a large quenching efficiency in upconversion luminescence (UCL). The cyanide-mediated redox reaction leads to the consumption of Au NPs, resulting in UCL recovery by the inhibition of the FRET process. On the basis of these features, csUCNP/Au nanoassemblies can serve as sensitive nanoprobes for cyanide ions with a detection limit of 1.53 μM. Moreover, no significant UCL variation was observed upon the addition of other interfering ions, showing the excellent selectivity of nanoprobes toward cyanide ion sensing. The easy preparation of such upconversion-based nanoprobes provides a promising platform for sensitive and selective sensing of other hazardous species.

中文翻译：

---

基于金修饰的上转换纳米组件的氰化物阴离子荧光传感

氰化物已被认为是毒性最高的化学物质之一，对环境和人类有害。在这里，已经通过在核壳结构的NaYF ₄上组装金纳米颗粒（NPs）来设计和制备用于氰化物阴离子的基于荧光共振能量转移（FRET）的上转换纳米探针：Yb，Er @ NaYF ₄：Yb上转换NP（csUCNP），其中csUCNP充当能量供体，Au NP充当能量受体。为了在上转换发光（UCL）中具有大的猝灭效率，对Au含量进行了优化。氰化物介导的氧化还原反应导致Au NP的消耗，通过抑制FRET过程导致UCL恢复。基于这些特征，csUCNP / Au纳米组件可作为氰化物离子的敏感纳米探针，检测极限为1.53μM。此外，添加其他干扰离子后未观察到明显的UCL变化，显示出纳米探针对氰化物离子感测的出色选择性。这种基于上转换的纳米探针的简便制备为其他危险物种的敏感和选择性感测提供了一个有希望的平台。