Detection of beta-glucans using an amperometric biosensor based on high-affinity interaction between Dectin-1 and beta-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 beta-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 beta-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 beta-glucans presented good accuracy, stability, and reproducibility. The proposed biosensor not only could be used for rapid analysis of serum beta-glucans but also provided a screening procedure for the determination of fungal infections. 2010 Elsevier Inc. All rights reserved.