Cu2+ induced Regulation and construction of FAD-Mb/Cu-Mb@AuNPs Bi-functional mimetic enzyme and application in glucose visualization detection

Abstract

FAD-Mb/Cu-Mb@AuNPs, a bi-functional mimetic enzyme (BME) was constructed through modification of gold nanoparticles (AuNPs) with flavine adenosine dinucleotide (FAD) and Cu2+ relayed on the mediation of methanobactin (Mb). Mb interacted with Au of AuNPs to form S-Au, which allowed the formation of Mb-AuNPs. The FAD and Cu2+ was bound to Mb of Mb-AuNPs through –CONH- and chelate of Cu2+ with 4-sulfonyl-5-hydroxyimidazole and 4-hydroxy-5-sulfonylimidazole, then FAD-Mb/Cu-Mb@AuNPs had been constructed. The FAD enhanced the glucose oxidase activity of BME and Cu2+ endowed it with high per-oxidase activity. The BME could be used for rapid visual detection of glucose under the condition of 40.0°C and pH 4.0. The BME was composed of Mb (1.6 mL, 10−4 mol/L) and AuNPs (15 nm) mixture (V:V = 1:1), FAD (6 μL, 2.4 × 10−3 mol/L) and CuSO4 (0.2 mL, 5 × 10−3 mol/L). The detection range of glucose was 20～80 mmol/L and the detection limit was 3.06 × 10−5 mol/L.