Determination of Small-Sized α-Synuclein Oligomers Using Solid-State Nanopore Assisted with Circular Single-Stranded...

Area of Science:

• Biophysics
• Nanotechnology
• Neuroscience

Background:

• Misfolded alpha-synuclein (αS) oligomers are key drivers of Parkinson's disease (PD) neurodegeneration.
• Small αS oligomers exhibit higher cytotoxicity than mature aggregates.
• Solid-state nanopores offer high-resolution single-molecule sensing but struggle with heterogeneous biomolecules like αS oligomers.

Purpose of the Study:

• To develop a quantitative method for determining αS oligomers of varying sizes using nanopore sensing.
• To enhance αS oligomer identification and classification using a circular single-stranded DNA (CssDNA) frame.
• To assess the selectivity of the CssDNA frame for αS oligomers against other proteins.

Main Methods:

• Utilized 10 nm silicon nitride (SiN_x) nanopores for resistive pulse sensing.
• Employed a CssDNA frame functionalized with an aptamer to capture αS oligomers.
• Analyzed translocation events of CssDNA-αS complexes to identify and classify oligomer species.

Main Results:

• Successfully identified and classified αS oligomers from dimers to heptamers based on translocation event analysis.
• Detected primarily dimeric αS oligomers after 0.5 h incubation with the CssDNA frame.
• Demonstrated high selectivity of the CssDNA frame by distinguishing αS oligomers from β-lactoglobulin, Aβ1-42, and tau proteins.

Conclusions:

• The developed nanopore sensing approach, assisted by a CssDNA frame, enables quantitative analysis of αS oligomers at the single-molecule level.
• This method provides a promising alternative for studying αS oligomer heterogeneity relevant to Parkinson's disease.
• The specificity of the CssDNA frame highlights its potential for targeted biomolecular detection.