Search

From farm to plate, food meets various challenges and pollution. Food detection is essential to ensure food safety. Although detection techniques have obtained great development, the accuracy, sensitivity and operating conditions still have room for improvement. Composed of dielectric media with different refractive indices to form a periodic structure, an optical material named photonic crystal (PC) can offer a breakthrough. Owing to the periodic structure, Bragg diffraction happens with optical waves propagating in a PC and photonic band gap (PBG), a characteristic parameter of the PC, will form. The properties of PBG are widely used in the field of detection. Combined with the techniques of biology, immunology, optics and fluorescence etc., PCs can play the role of specific, efficient, sensitive and convenient sensors in food detection. At present, PCs have been successfully applied to analyze hazardous substances in food, such as microorganisms, biotoxins, veterinary drug residues, pesticide residues, excessive additives, illegal additives, environmental pollutants and heavy metal composition. This article introduces PCs about the fabrication methods, principles and techniques applied in detection and research progress in food detection. [ABSTRACT FROM AUTHOR]

Based on the demonstration of molecular imprinting technology, photonic crystal technology and the technology of molecularly imprinted photonic crystal, the relevant researches on the application of molecularly imprinted photonic crystal technology in the detection of toxic and harmful substances in food (veterinary drug residues, pesticide residues, biological toxins, endocrine disruptors, illegal additives) and nutrients was combed. It pointed out that molecularly imprinted photonic crystal technology combined the high selectivity of molecular imprinting technology to the target and the unique optical properties of photonic crystals, and was suitable for food detection as a new optical sensor. Compared with the traditional food detection methods, molecularly imprinted photonic crystal technology greatly improved the detection efficiency, shortened the detection time, improved the visual detection degree, and was more conducive to the development of field detection. However, molecularly imprinted photonic crystal technology also had the disadvantages of complex synthesis process, large amount of organic reagents, narrow detection range and poor repeatability. Researchers could make further research in the future on developing environment-friendly green synthesis methods, enhancing the stability and controllability of photonic crystals, reducing the nonspecific adsorption of molecularly imprinted photonic crystals, developing high-throughput detection methods suitable for simultaneous detection of multiple targets, and expanding the application in the field of microbial detection to optimize and develop molecularly imprinted photonic crystal technology. [ABSTRACT FROM AUTHOR]