MnO2 nanoparticles/methylene blue-chitosan nanocomposite modified glassy carbon electrode (MnO2 NPs/MB–CS/GCE) as sensor for electrochemical determination of β-glucan in Morchella esculenta samples

Abstract

The aim of this work was performed for design the electrochemical biosensor (βg-GOx/MnO2 NPs/MB-CS/GCE) determination of β-glucan in morel samples by modification of glassy carbon electrode (GCE) with electrodeposition of methylene blue-chitosan (MB-CS) nanocomposite and MnO2 nanoparticles (MnO2 NPs) and immobilization β-glucanase and glucose oxidase (βg-GOx), respectively. The study of the morphology of MnO2 NPs/MB–CS/GCE by FE-SEM indicated that the electrodeposited MnO2 NPs in the chitosan layer are wrapped by MB nanocubes. The electrochemical properties of β-glucan nonconductive enzyme film were successfully immobilized in β-glucan/MnO2 NPs/MB-CS/GCE, and the synergetic advantageous effect of MB-CS and MnO2 NPs enhanced the sensitivity and selectivity of the β-glucan biosensor. The linear range of 0– 10,400 ng/mL was obtained, and the sensitivity of 0.00441 µA/ng.mL−1 and the detection limit of 0.34 ng/mL were determined. The study on the applicability of the βg-GOx/MnO2 NPs/MB–CS/GCE as β-glucan sensor in morel samples revealed significant conformity between the results of amperometric and β-Glucan Assay Kit assays, and the obtained good recoveries between 90.00% and 97.50% with relative standard deviation less than 5.18% for amperometric analysis were acceptable, confirming the appropriate applicability of the βg-GOx/MnO2 NPs/MB–CS/GCE for determination of the β-glucan content in fungal samples.