An Electrochemical Sense Array Based on Aptamer and Biotin-Avidin System for the Selective Detection of Glucagon-Like...

GLP-1 as an incretin, has the ability to decrease blood sugar levels in a glucose-dependent manner by enhancing the secretion of insulin. Besides the insulinotropic effects, GLP-1 has been associated with numerous regulatory and protective effects. Thus, the action of GLP-1 is preserved in patients with type 2 diabetes and substantial pharmaceutical research has therefore been directed towards the development of GLP-1-based treatment.

In this work, we reported an electrochemical sense array based on the aptamer and biotin-avidin system for the detection of glucagon-like peptide-1 (GLP-1). The sense array employed a "stem-loop" conformation ap-tamer which was immobilized on the electrode of the 16-unit gold array via pre-labeled thiol group (-SH). Pre-labeled biotin serves as an affinity tag for the binding of avidin-horseradish peroxidase (avidin-HRP). The stem-loop structure of the aptamer kept the biotin from being approached by a bulky avidin-HRP by means of the steric hindrance. After the interaction of the target (GLP-1) and the aptamer, the aptamer would undergo a significant conformational change to force biotin away from the electrode, giving the avidin-HRP easy access to the labeled biotin. The HRP in the substrate could sensitively transduce the concentration of GLP-1 into the electrical signals, which were then measured by electrochemical technology of cyclic voltammetry and amperometric i-t curve.

Under the optimal experimental conditions, the proposed sense array for GLP-1 had a good linear relationship from 0.1 pmol/L to 20 pmol/L with a detection limit of 0.05 pmol/L and can be used to accurately detect the GLP-1 in serum.

The experimental results show that GLP-1 could be selectively detected by the electrochemical sense array, indicating that the proposed sense array based on the biotin-avidin system and the stem-loop aptamer has great potential in the detection of GLP-1.