Design of an aptamer – based fluorescence displacement biosensor for selective and sensitive detection of kanamycin in aqueous samples

Abstract

A label-free detection method for kanamycin A using an aptamer-based biosensor has been developed. To start with, some commonly used DNA G-quadruplex structure sensitive dyes were evaluated and it was verified that the thioflavin T–G-quadruplex DNA complex was useful for constructing a fluorescent displacement biosensor. The limit of detection and the dynamic detection range of this sensor for kanamycin A is 300 pM and 1 nM to 300 μM, respectively, which are comparable to or better than the results for most reported methods, particularly for almost all the optical ones. The kanamycin recovery is in the range from 94% to 105%. The success of this new method is the creation of a new type of displacement biosensor which can be made widely applicable for probing quadruplex DNA–ligand interactions and thus there is the potential that a handful of analytes including small molecules, oligonucleotides and proteins could be detected using it.