Detection of acetylcholinesterase and its inhibitors by liquid crystal biosensor based on whispering gallery mode

In this work, a liquid crystal (LC) biosensor based on whispering gallery mode (WGM) lasing is reported and demonstrated for real-time and high-sensitive detection of acetylcholinesterase (AChE) and its inhibitors. Benefit from the double amplification by the WGM resonance and the 5CB molecules, small changes in biological processes are significantly enhanced in WGM spectral responses. The spectral responses provide direct information about the molecular adsorption/desorption at the LC/aqueous solution interface and can be used as an indicator of the enzymatic reaction. The limit of detection achieved was as low as 0.1 pg/mL for fenobucarb and 1 pg/mL for dimethoate, which is considerably lower than the standard levels of pesticides specified for water quality standards. Results indicate that this versatile method holds prospects for application in real-time and high-sensitive monitoring of biochemical reactions and can serve as an alternative solution to compensate for missing capabilities in conventional POM observations.