Design of a Liquid Crystal-Based Sensor for Ultrasensitive Detection of Sunset Yellow

Sunset yellow (SUN) is one of the popular synthetical food colorants which are a member of the class azo dyes and in food industries greatly used. An excess consumption of SUN can cause to behavioral symptoms including of hyperactivity, inattentiveness, cancer, and some further health effects. Hence, it is important to detect this food colorant effectively to reduce risk. Herein, an innovative liquid crystal (LC)-based sensor was designed for the label-free and ultra-sensitive detecting of the SUN by means of a cationic surfactant-decorated LC interface. The nematic liquid crystal in contact with CTAB revealed a homeotropic alignment, when SUN was injected into the LC-cell, the homeotropic alignment consequently altered to a planar one by electrostatic interactivities between SUN and CTAB. The designed LC-based sensor detected SUN at too much trace level as low as 0.5 aM with analogous selectiveness. The suggested LC-based sensor is a rapid, convenient, and simple procedure for label-free detection of SUN in food industrial and safety control application.