Abstract
Solid-state nanopores are versatile tools for single molecule sensing. Because their sizes can be tuned from few nm until hundreds nanometers, they are particularly promise to characterize the biomacromolecule assembly. We were interested by the detection of amyloid fibril obtained from model proteins. To reach this goal three main problems have to be tackle. First, the protein unfolding usually promotes the adsorption at solid/liquid interfaces especially by non-electrostatic interactions inducing the nanopore fouling. Second, the protein amyloid fibrils are more rigid than polymer chain. Thus their translocations require an important energy overcome to barrier of entrance and the one to escape. This is amplified by the adsorption. Finally, the characterization of the fibrillation kinetic imposes to work with very stable nanopores. We have produced different nanopores to evaluate their potentiality for amyloid fibril detection. Then, these nanopores were functionalized with PEG chain, in order to prevent the unspecific adsorption and improve their lifetime. We have studied the translocation of small protein aggregate as well as large fibrils through these nanopores. The SiN nanopore coated with PEG is limited to the detection of small protein aggregate. However, it allows the relative current blockade is related to the morphology of the aggregate. The conical nanopore on PET performed by track-etched technique is the most suitable to follow the growing of amyloid fibril due to a longer lifetime and an optimum geometry which allow to decrease the energy barrier of entrance.