Single Molecule Nanopore Spectrometry for Peptide Detection

Area of Science:

• Biophysics
• Analytical Chemistry
• Materials Science

Background:

• Single molecule nanopore spectrometry (SMNS) offers potential for molecular size discrimination.
• Previous studies demonstrated SMNS for differentiating polyethylene glycol (PEG) molecules.
• Extending SMNS to water-soluble peptides is vital for various bioapplications.

Purpose of the Study:

• To enhance single molecule nanopore spectrometry (SMNS) for sensing water-soluble peptides.
• To investigate the impact of Au25(SG)18 clusters on peptide-nanopore interactions.
• To analyze the role of fluctuations and solution conditions in peptide detection.

Main Methods:

• Utilized Au25(SG)18 clusters to modulate peptide on- and off-rates to the nanopore.
• Investigated the effect of solution conditions (pH, chaotropic salt) on peptide flexibility and current blockade fluctuations.
• Developed a model correlating current blockade depths to peptide mass.

Main Results:

• Au25(SG)18 clusters were employed to enhance peptide binding kinetics.
• Increased peptide flexibility via solution modification reduced current blockade fluctuations by nearly 2-fold.
• Enhanced SMNS improved mass resolution by over 2-fold for cationic peptides.

Conclusions:

• Optimized SMNS, incorporating Au25(SG)18 clusters and controlled solution conditions, significantly improves water-soluble peptide sensing.
• The study provides a model linking peptide mass to current blockade depth, enhancing sensor accuracy.
• These advancements are critical for advancing bioanalytical applications relying on peptide characterization.