State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Molecular Science and Biomedicine Laboratory, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha 410082, P. R. China.
Anal Chem. 2020 Mar 17;92(6):4623-4629. doi: 10.1021/acs.analchem.0c00164. Epub 2020 Mar 5.
The label-free assay has drawn extensive attention because it does not require a labeling step and enables direct interaction and signal transduction between the sensing unit and target analytes. Herein, we demonstrate a proof-of-principle concept of a label-free and visualized nanoplasmonic strategy for silver ions sensing, where only TiC MXenes are employed by exploring their excellent adsorption affinity and reductive property toward metal ions. Ag was adsorbed onto the surface of TiC MXene nanosheets, followed by the TiC MXenes mediated in situ silver nanoparticles (Ag NPs) generation without adding any extra stabilizing or reducing agent. The excellent localized surface plasmon resonances at a particular wavelength provide Ag NPs the capability for colorimetric assay with a detection limit of 0.615 μM. With the assistance of a smartphone, RGB analysis exhibited visualized results consistent with the results measured on a UV-vis spectrometer, promising a budget, simple-operating on-site detection. Moreover, the detection of Ag in real samples was achieved with satisfactory results meeting the analysis demand for the Drinking Water Standards of the World Health Organization (WHO) and the United States Environmental Protection Agency (U.S. EPA). These results reveal that TiC MXenes possess great potential in building convenient label-free colorimetry nanoplatforms and may evoke more inspirations to explore strategies for the direct sensing of analytes.
无标记检测法引起了广泛关注，因为它不需要标记步骤，可以实现传感单元与目标分析物之间的直接相互作用和信号转导。在此，我们展示了一种无标记和可视化纳米等离子体策略用于银离子传感的原理验证概念，其中仅使用 TiC MXenes 通过探索其对金属离子的优异吸附亲和力和还原性能来实现。Ag 被吸附到 TiC MXene 纳米片的表面上，然后在没有添加任何额外稳定剂或还原剂的情况下，通过 TiC MXenes 介导的原位银纳米颗粒（Ag NPs）生成。在特定波长下的优异局域表面等离子体共振使 Ag NPs 具有比色测定的能力，检测限为 0.615 μM。借助智能手机，RGB 分析显示出与在紫外-可见分光光度计上测量的结果一致的可视化结果，有望实现低成本、简单操作的现场检测。此外，还实现了对实际样品中 Ag 的检测，结果令人满意，满足世界卫生组织（WHO）和美国环境保护署（U.S. EPA）的饮用水标准的分析要求。这些结果表明，TiC MXenes 在构建方便的无标记比色纳米平台方面具有巨大潜力，并可能激发更多灵感来探索直接传感分析物的策略。
