Simple and Rapid Detection of Ibuprofen─A Typical Pharmaceuticals and Personal Care Products─by a Liquid Crystal Aptasensor

This work established a liquid crystal (LC) aptasensor for simple and rapid detection of ibuprofen, a typical pharmaceuticals and personal care products (PPCPs) pollutant. A negatively charged DNA aptamer specific for ibuprofen and a positively charged amphiphilic surfactant, hexadecyltrimethylammonium bromide (CTAB), were incubated with the sample and then directly added onto the LC interface. In the presence of ibuprofen, the specific binding of ibuprofen with the DNA aptamer will release CTAB, which then adsorbed at the LC-aqueous interface and induced the orientational change of LCs to homeotropic orientation with a dark optical signal output. While in the absence of ibuprofen, the DNA aptamer binds with CTAB through hydrophobic and electrostatic interactions, LCs remained in the planar orientation with a bright optical signal output. This LC aptasensor also has good specificity for ibuprofen and can even detect ibuprofen drug in tap water. Moreover, the response time of the LC aptasensor is fast in minutes. Additionally, this LC aptasensor benefits in monitoring the water quality and inspires the exploration of a general platform for PPCPs detection.