A food safety gadget for acrylamide determination: Aptamer placement at surfactant-liquid crystal interface

A tag-free and sensitive aptasensor was introduced to quantify acrylamide based on pursuing the directional order of liquid crystal molecules (LCs) at the surfactant-decorated interface. The hydrophobic interaction of surfactant tails and LCs induced their well-ordered vertical design. The regular alignment of LCs was perturbed through the electrostatic interaction of the specific aptamer with the surfactant head, which altered the polarized texture of the aptasensor from dark to bright optical appearance. However, in the presence of acrylamide and its specific interaction with aptamer strand, LCs arranged vertically with a dark polarized texture. Using the designed aptasensor, acrylamide was detected over the ranges of 1 fmol L-1 to 1 nmol L-1 and 1 nmol L-1 to 50 mu mol L-1 with the detection limit (LOD) of 0.28 fmol L-1 and the recovery value of 92.36-101.35%. Besides, the aptasensor successfully quantified acrylamide in the diverse real samples including decaffeinated coffee (36 mu g kg-1), roasted coffee (159 mu g kg-1), roasted date seeds (13-369 mu g kg-1) and roasted quince (1556 mu g kg-1). Acrylamide content of cocoa and instant date seed powder were less than LOD. The detection methodology described in this study provides a sensitive, facile, rapid and portable tool for LC-based sensing of acrylamide.