The construction of covalent organic frameworks - photonic crystal employed for label-free detection of AFB1

Covalent organic framework (COF) materials have the advantages of good chemical stability, regular pores, high specific surface area, and it is widely used in adsorption, catalysis, and biosensors. However, the construction of photonic crystal (PC) with COF remains a challenge. In this work, we developed a new type of COF PC, which had an inverse opal array structure, called covalent organic framework - inverse opal photonic crystal (COF-IOPC). The COF-IOPC was prepared by sacrificial template method, which was simple and rapid. The SiO 2 microspheres was used to prepare the opal template through the restricted meniscus self-assembly method, and then, the COF pre-reaction solution was added to fulfill the crevices of the opal template. By controlling the size of the SiO 2 particles of the opal template, the photonic band gap of the COF-IOPC could be manipulated to exhibit different structural colors. Furthermore, the COF-IOPC could be used to detect Aflatoxin B 1 (AFB 1 ) without label. The spiked real samples were detected through the national standard method Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/MS) as comparison, and the results indicated that COF-IOPC sensing method had a well accuracy with the LC-MS/MS method. The successful construction of this novel material further expands the application field of COF material.