Electrochemical Aptasensor of Human Cellular Prion Based on Multiwalled Carbon Nanotubes Modified with Dendrimers: A Platform for Connecting Redox Markers and Aptamers

The present work aims to develop an electrochemical biosensor based on aptamer able to detect human cellular prions PrPC as a model biomarker of prion disease with high sensitivity. We designed the biosensor using multiwalled carbon nanotubes (MWCNTs) modified with polyamidoamine dendrimers of fourth generation (PAMAM G4) which in turn were coupled to DNA aptamers used as bioreceptors. Electrochemical signal was detected by a ferrocenyl redox marker incorporated between the dendrimers and aptamers interlayer. MWCNTs, thanks to their nanostructure organization and electrical properties, allow the distribution of aptamers and redox markers over the electrode surface. We demonstrated that the interaction between aptamers and prion proteins leads to variation in the electrochemical signal of the ferrocenyl group. High sensitivity with a detection limit of 0.5 pM and a wide linear range of detection from 1 pM to 10 μM has been demonstrated. Detection of PrPC in spiked blood plasma has been achieved in the same...