Optical detection of the ligand–receptor binding by anchoring transitions of liquid crystals

An optical detection system of the specific binding events between ligands and bioreceptors was developed using the anchoring transitions of a liquid crystal (LC). The specific binding of ligand–receptor pairs on a modified surface disturbs the orientational order of the LC and induces the anchoring transition from the homeotropic to the homogeneous LC alignment. Since the initial homeotropic alignment is preserved in the absence of the binding process, the binding events are easily monitored by a simple optical system through the LC texture change. This concept of the optical detection would be useful for designing a variety of biosensors.