Detection of β-glucans using an amperometric biosensor based on high-affinity interaction between Dectin-1 and β-glucans

Early diagnosis of fungal infection plays an important role in increasing antifungal therapeutic response, but meaningful tests such as microbiological cultures and histopathological diagnosis are usually insensitive and time-consuming. A sensitive amperometric biosensor for β-glucans was fabricated by immobilizing Dectin-1 onto Nafion–thionine–gold nanoparticle–chitosan multilayer films to trap its corresponding ligand from sample solution. On formation of ligand–receptor complex, detection of β-glucans was accomplished by monitoring the decrease of the electrochemical signal of the modified electrode due to the inhibition of the transmission of electrons. Dectin-1 was constructed by cloning the extracellular carbohydrate recognition domain of the mouse Dectin gene into the pET28a(+) prokaryotic expression vector. Optimal conditions and analytical performances of the described biosensor were investigated. Under the optimal conditions, the biosensor response for β-glucans presented good accuracy, stability, and reproducibility. The proposed biosensor not only could be used for rapid analysis of serum β-glucans but also provided a screening procedure for the determination of fungal infections.