College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Rd, Hangzhou, Zhejiang, 310058, China; Key Laboratory of on Site Processing Equipment for Agricultural Products, Ministry of Agriculture and Rural Affairs, China; Key Laboratory of Intelligent Equipment and Robotics for Agriculture of Zhejiang Province, China.
State Key Lab of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
Biosens Bioelectron. 2022 Aug 1;209:114274. doi: 10.1016/j.bios.2022.114274. Epub 2022 Apr 11.
Development of rapid molecular detection technologies is critical for the safer and smarter urban agriculture, medicine, and pro-environment. The emergent terahertz (THz) spectroscopy has its distinct advantages of being non-destructive, label-free and able to trace intermolecular and intramolecular vibrations, yet it suffers from the low performance of sensing materials available and their high fabrication cost. Here, we introduce a reticular material -- two dimensional (2D) covalent organic frameworks (COFs) and prepare their nanofilms as the lossy layer for THz absorbers. The COF film can be directly deposited on the dielectric layer of THz absorbers via an in-situ wet-chemistry growth. It possesses designable hierarchical structures, high specific areas of 736-971 m/g, and precise nanopores of 1.6-2.1 nm, depending on its 2D COF constituents. The resulting THz absorber has been tested for pesticide detection. It presents a limit of detection at 2.2 ng and a selective response of 2.7-7.8 times that of interferents such as saccharides, antibiotics, and dyes, satisfying the need for practical application. Such flexible filmy sensor can measure the pesticide residue on the surface of apple for practical application. The THz sensor also demonstrates high stability over 1000 cycles of bending. Use of reticular nanofilm as the responsive layer may permit the future development of high-performance THz absorbers and other sensors for rapid molecular recognition.
快速分子检测技术的发展对于更安全、更智能的城市农业、医学和环保至关重要。新兴的太赫兹（THz）光谱技术具有非破坏性、无标记以及能够追踪分子间和分子内振动的独特优势，但它受到可用传感材料性能和制造成本高的限制。在这里，我们介绍了一种网状材料——二维（2D）共价有机框架（COFs），并将其纳米薄膜制备为太赫兹吸收体的损耗层。COF 薄膜可以通过原位湿法化学生长直接沉积在太赫兹吸收体的介电层上。它具有可设计的分层结构、736-971 m/g 的高比表面积和 1.6-2.1nm 的精确纳米孔，具体取决于其二维 COF 组成。所制备的太赫兹吸收体已用于农药检测。它的检测限为 2.2ng，对干扰物如糖类、抗生素和染料的选择性响应为 2.7-7.8 倍，满足实际应用的需要。这种灵活的薄膜传感器可用于测量苹果表面的农药残留，用于实际应用。太赫兹传感器在 1000 次弯曲循环后仍具有高稳定性。使用网状纳米薄膜作为响应层可能会促进未来开发用于快速分子识别的高性能太赫兹吸收体和其他传感器。
