An Ultrasensitive Liquid Crystal Aptasensing Chip Assisted by Three-Way Junction DNA Pockets for Acrylamide Detection in Food Samples

Abstract

Acrylamide, an unsaturated amide found in heat-processed foods, poses serious risks to human health due to its neurotoxicity, carcinogenicity, and genotoxicity. This highlights the importance of quantitative monitoring of acrylamide in foods and the environments to ensure public health safety. Therefore, there is an urgent need for simple, rapid, and highly sensitive methods to accurately quantify acrylamide. In the present study, a user-friendly aptasensor was designed to quantify ultra-low levels of acrylamide in nuts for the first time. This innovative approach utilizes chemical engineering of a glass slide as a portable sensing platform, which incorporates liquid crystal (LC) molecules and a three-way junction (TWJ) DNA pocket. The immobilized TWJ pocket can disrupts the vertical alignment of LCs, turning the dark polarized background of the aptasensor to a colorful state. The binding of the specific aptamer to acrylamide disrupts the TWJ structure, enabling the LCs to return to their homotropic alignment. This structural change restores the dark polarized view of the sensing platform. The TWJ-engineered LC aptasensor effectively detects ultra-low concentrations of acrylamide in the range of 0.0005 to 50 fmol/L, with a detection limit of 0.106 amol/L. The aptasensor was successfully applied to real roasted nut samples, including peanut, almond, pistachio, and hazelnut, achieving recovery values ranging from 96.84% to 99.61%. With its simplicity, portability, ease of use, and cost-effectiveness, this aptasensor is a powerful sensing device for food safety monitoring.

Environmental implication

Acrylamide is a thermal processing contaminant that forms in foods subjected to frying, toasting, and roasting. Furthermore, its high solubility in water raises significant concerns about environmental contamination, particularly through industrial effluents and agricultural runoff. Given the health risks associated with acrylamide, such as neurotoxicity, carcinogenicity, and genotoxicity, there is an urgent need for a sensitive, specific, and rapid technique to accurately determi ne its content in both food and the environment. To address this need, we introduced a simple, rapid, and cost-effective aptasensing strategy. This approach involves the chemical engineering of a glassy slide as a portable sensing platform, incorporating liquid crystal molecules and a three-way junction DNA pocket for efficient detection.