Institute of Intelligent Machines Institution, Chinese Academy of Sciences, Hefei, 230031, P.R. China.
Department of Chemistry, University of Science and Technology of China, Hefei, 230026, P.R. China.
Chemistry. 2018 Mar 15;24(16):4094-4102. doi: 10.1002/chem.201705700. Epub 2018 Feb 16.
Liquid interfacial self-assembly of metal nanoparticles holds great promise for its various applications, such as in tunable optical devices, plasmonics, sensors, and catalysis. However, the construction of large-area, ordered, anisotropic, nanoparticle monolayers and the acquisition of self-assembled interface films are still significant challenges. Herein, a rapid, validated method to fabricate large-scale, close-packed nanomaterials at the cyclohexane/water interface, in which hydrophilic cetyltrimethylammonium bromide coated nanoparticles and gold nanorods (AuNRs) self-assemble into densely packed 2D arrays by regulating the surface ligand and suitable inducer, is reported. Decorating AuNRs with polyvinylpyrrolidone not only extensively decreases the charge of AuNRs, but also diminishes repulsive forces. More importantly, a general, facile, novel technique to transfer an interfacial monolayer through a designed in situ reaction cell linked to a microfluidic chip is revealed. The self-assembled nanofilm can then automatically settle on the substrate and be directly detected in the reaction cell in situ by means of a portable Raman spectrometer. Moreover, a close-packed monolayer of self-assembled AuNRs provides massive, efficient hotspots to create great surface-enhanced Raman scattering (SERS) enhancement, which provides high sensitivity and reproducibility as the SERS-active substrate. Furthermore, this strategy was exploited to detect drug molecules in human urine for cyclohexane-extracted targets acting as the oil phase to form an oil/water interface. A portable Raman spectrometer was employed to detect methamphetamine down to 100 ppb levels in human urine, exhibiting excellent practicability. As a universal platform, handy tool, and fast pretreatment method with a good capability for drug detection in biological systems, this technique shows great promise for rapid, credible, and on-spot drug detection.
液体界面处的金属纳米颗粒自组装在可调谐光学器件、等离子体学、传感器和催化等领域具有广泛的应用前景。然而，构建大面积、有序、各向异性的纳米颗粒单层膜以及获得自组装界面膜仍然是重大挑战。在此，报道了一种在环己烷/水界面上快速、验证的大面积、紧密堆积纳米材料制备方法，其中亲水性十六烷基三甲基溴化铵（CTAB）包覆的纳米颗粒和金纳米棒（AuNRs）通过调节表面配体和合适的诱导剂自组装成密集的二维阵列。聚维酮（PVP）修饰 AuNRs 不仅广泛降低了 AuNRs 的电荷，还减小了排斥力。更重要的是，揭示了一种通用、简便、新颖的技术，通过与微流控芯片相连的设计原位反应池来转移界面单层膜。自组装的纳米薄膜可以自动沉降在基底上，并通过便携式拉曼光谱仪在原位反应池中直接进行检测。此外，自组装的 AuNRs 紧密堆积单层膜提供了大量高效的热点，以产生巨大的表面增强拉曼散射（SERS）增强，作为 SERS 活性基底，具有高灵敏度和重现性。此外，该策略被用于检测人尿中环己烷提取目标物作为油相形成油/水界面的药物分子。便携式拉曼光谱仪用于检测人尿中的甲基苯丙胺，达到 100 ppb 以下的水平，表现出优异的实用性。作为一个通用平台、便捷工具和快速预处理方法，具有在生物体系中进行药物检测的良好能力，该技术在快速、可靠和现场药物检测方面具有广阔的应用前景。
