Label-free fluorometric assay for acetylcholinesterase and inhibitor screening based on supramolecular assemblies

Abstract

A new, easily prepared, inexpensive and facile fluorometric assay method for screening of acetylcholinesterase (AChE) and its inhibitor is successfully established with the supramolecular assemblies of myristoylcholine and heparin. Myristoylcholine, an amphiphilic compound, is chosen as the cationic surfactant as well as the substrate for AChE. The environment-dependent dye pyrene, encapsulated in hydrophobic interiors of the supramolecular assemblies, works as the fluorescent probe. This new assay method is designed to monitor the release of the encapsulated fluorescent probe from supramolecular assemblies triggered by an enzyme hydrolysis process. Such a strategy is appealing; organic synthesis was not required due to the use of the supramolecular assembly. The supramolecular assembly system allows for the sensitive assay of AChE with a limit of detection (LOD) as low as 4 mU mL⁻¹. The results also clearly demonstrate the usefulness of this fluorometric assay method for screening inhibitors of AChE. Given its inexpensive, simple and easy operation, this method may extend to high-throughput screening of AChE inhibitors and relevant Alzheimer's disease (AD) drug discovery.