A sensitive electrochemical immunosensor for prion detection based on poly-β-cyclodextrin/gold nanoparticles/glassy carbon electrode

In this work, we developed a sensitive electrochemical immunosensor for prion detection based on poly-beta-cyclodextrin (P beta-CD)/gold nanoparticles (AuNPs) modified electrode. Here, P beta-CD film provided lots of beta-CD units to capture the prion antibody by host-guest interaction. In the presence of prion, the specific interaction between prion and its antibody brought prion protein to the electrode surface to block the electron transfer channel of [Fe(CN)(6)](3-/4-) ions provided by the inner cavity of beta-CD, resulting in the decrease of the redox currents of [Fe(CN)(6)](3-/4-) ions. Based on this kind of blocking effect, prion protein was detected sensitively. Under the optimal conditions, the developed immunosensor showed a linear response range from 15 fM to 1500 fM with a low detection limit of 2.1 fM (3 sigma). By changing the specific antibody, this strategy could be easily extended to detect the infectious isoform of prion (PrPsc) and other proteins. Based on its low cost (second antibody-free and label-free) and high sensitivity, the developed method shows great potential applications in diagnosis of prion diseases at presymptomatic stage and bioanalysis. (C) 2017 Elsevier B.V. All rights reserved.