Preparation of Flavin Adenine Dinucleotide Aptamer-Based Sensor and Its Application for Glucose Detection

An flavin adenine dinucleotide (FAD) aptamer-based sensor was constructed with gold nanoparticles (AuNPs) as the main body, and methanobactin (Mb) and FAD as the ligands. Mb was used to wrap AuNPs, which has a strong adsorption capacity for Mb, to form a stable Mb-AuNPs structure. The Mb-AuNPs structure was used to modify the surface of the bare gold electrode by the drip-coating method, and FAD was introduced into the Mb-AuNPs structure, in which the‒COOH groups could firmly bind to FAD, to improve the ability to recognize glucose. As a result, a novel aptamer biosensor with glucose oxidase-like activity could be constructed. Cyclic voltammetry and the time-current curve method were used to explore the feasibility of its application in glucose detection. At 25 ℃ and pH 7.2, there was a good linear relationship between glucose concentration in the range of 10–200 μmol/L and the response current of the biosensor, with a correlation coefficient (R²) of 0.99791, and the detection limit was 4.22 × 10^-8 mol/L (R_SN = 3). The aptamer-based sensor has several advantages such as simple preparation, low price, easy operation and rapid detection.