Designing a Label Free Aptasensor for Detection of Methamphetamine

Abstract

A label-free electrochemical nucleic acid aptasensor for the detection of methamphetamine (MA) by the immobilization of thiolated self-assembled DNA sequences on a gold nanoparticles-chitosan modified electrode is constructed. When MA was complexed specifically to the aptamer, the configuration of the nucleic acid aptamer switched to a locked structure and the interface of the biosensor changed, resulting in a variation of the corresponding peak current of an electrochemical probe ([Fe(CN)₆]^3-/4-). Two different methods of cyclic voltammetry (CV) and microcantilever were employed to determine MA detection limit. Under the optimized experimental conditions, the presented sensor exhibits a nice specificity towards MA. The detection limits for MA in electrode and microcantilever were obtained 10 and 0.7 nM. The proposed aptasensor can be easily regenerated by the denaturalization of aptamer-target complexes in a heated water bath at 80-90 °C. Besides, this biosensor has a high reproducibility and selectivity, which can be a promising method to detect MA in real samples.