Fast Probing Amyloid Polymorphism via Nanopore Translocation

Abstract

Neurodegenerative diseases are characterized by the presence of cross-β-sheet amyloid fibrils and a rich mesoscopic polymorphism, requiring noninvasive detection with high fidelity. Here, we introduce a methodology that can probe via a sensitive synthetic nanopore the complex polymorphism of amyloid fibrils by an automated and fast screening protocol. Statistically analyzing the translocation events on two model amyloid systems derived from β-lactoglobulin and lysozyme allows extracting the cross-sectional configuration of hydrated amyloid fibrils from current block amplitude and correlating dwell time with fibril length. These findings are consistent with the amyloid polymorphs observed in solution by atomic force microscopy. Furthermore, the ionic current signal of a single translocation event can reveal abnormally aggregated conformations of amyloid fibrils without potential artifacts associated with microscopy methods. This study introduces an effective approach to physically discriminating and separating amyloid and may serve in the rapid diagnosis of early aggregating pathological amyloidosis.

Exploring single-molecule interactions: heparin and FGF-1 proteins through solid-state nanopores

“…The characterization and discrimination of amyloid particles through nanopores further extend the scope of disease identification, allowing the observation of disease progression as these particles are identified as biomarkers associated with neurological diseases. 46,47 O'Donohue et al . demonstrated the successful classification of the monomeric and dimeric forms of human serum transferrin receptor proteins through SSNs and confirmed the coexistence of both forms in a heterogeneous mixture.…”

Label-free and amplification-free viral RNA quantification from primate biofluids using a trapping-assisted optofluidic nanopore platform

“…Nanopore detection is based on changes in ionic current across a membrane with a nanoscopic opening as a particle passes (translocates) through this nanopore ( 21 ). This principle now forms the basis of commercial next-generation DNA sequencing technology ( 22 ) but has also been used to detect other biomolecules, including DNA ( 23 – 25 ), RNA ( 26 , 27 ), proteins ( 28 , 29 ), whole virus ( 30 , 31 ), and small molecules ( 32 , 33 ). Thus, nanopores offer outstanding (single-molecule) sensitivity and great simplicity due to their label-free transduction mechanism.…”