Satheeshkumar Elumalai, Yang Jyisy, Srinivasadesikan Venkatesan, Lin Ming-Chang
Department of Chemistry, National Chung Hsing University.
Center for Interdisciplinary Molecular Science and Department of Applied Chemistry, National Chiao Tung University.
Anal Sci. 2017;33(10):1115-1121. doi: 10.2116/analsci.33.1115.
In this work, a simple method was developed to simultaneously fabricate silver nanoparticles (AgNPs) and modify their surfaces with recognition functional groups for colorimetric detection of Cu ions. To prepare the AgNPs with proper functional group on their surface for detection of Cu ions, photochemical reaction was employed and a photoactive species of tyrosine (Tyr) was used to trigger the photoreduction of AgNPs, while the oxidized Tyr (Tyr) was used to functionalize the AgNPs surface at the same time. To understand the behaviors, the prepared color AgNPs colloidal solution was characterized by UV-visible spectrometer, FT-IR spectrometer, dynamic light scattering (DLS), X-ray photoelectron spectrometer (XPS) and density functional theory (DFT). Based on DFT calculation results, Tyr was adsorbed on the surface of AgNPs by the quinone ring and its functional group of amino acid was freely exposed to the aqueous media for rapid interaction of Cu ions. Based on detection of different metal ions, Tyr@AgNPs were selective to interact with Cu ions through formation of highly stable Cu-Tyr@AgNPs complexes. The evidence in formation of Cu-Tyr@AgNPs complex could be obtained through the red shift of the surface plasmonic resonance (SPR) band of Tyr@AgNPs located at 557 nm, which gives a color change from light yellow to brown color allowing visual identification of Cu ions for rapid screening purposes. For quantitative analysis, a band intensity ratio of A/(A-A) was constructed to correlate with the concentration of Cu ions. A linear range up to 10 μM with a detection limit close to 150 nM was found.
在本工作中，开发了一种简单的方法，用于同时制备银纳米颗粒（AgNPs）并使用识别功能基团对其表面进行修饰，以用于比色检测铜离子。为了制备表面带有合适功能基团以检测铜离子的AgNPs，采用了光化学反应，使用酪氨酸（Tyr）的光活性物种引发AgNPs的光还原，同时使用氧化型酪氨酸（Tyr）对AgNPs表面进行功能化。为了解其行为，通过紫外可见光谱仪、傅里叶变换红外光谱仪、动态光散射（DLS）、X射线光电子能谱仪（XPS）和密度泛函理论（DFT）对制备的彩色AgNPs胶体溶液进行了表征。基于DFT计算结果，Tyr通过醌环吸附在AgNPs表面，其氨基酸功能基团自由暴露于水介质中，以便与铜离子快速相互作用。基于对不同金属离子的检测，Tyr@AgNPs通过形成高度稳定的Cu-Tyr@AgNPs络合物而选择性地与铜离子相互作用。通过位于557nm处的Tyr@AgNPs表面等离子体共振（SPR）带的红移可以获得形成Cu-Tyr@AgNPs络合物的证据，这导致颜色从浅黄色变为棕色，从而可以目视识别铜离子以进行快速筛选。对于定量分析，构建了A/(A-A)的带强度比与铜离子浓度相关。发现线性范围高达10μM，检测限接近150 nM。
