Thiol-Enhanced Nanopore Sensing of Cysteine-Containing Peptides

Abstract

Nanopore sensing, first conceived more than three decades ago, has seen rapid advancements in recent years in its capability in single-molecule sensing. Following immense success in nucleic acid sequencing, increased efforts have been directed to probing other biomolecules such as proteins. In recent years, our group has investigated the enhancement of nanopore sensing of peptide signals by introducing gold clusters to the pore. Gold clusters have been shown to prolong peptide occupation times in the pore, permitting the observation of unique characteristic signals related to the peptide’s kinetics that are not otherwise observable. While the ability to sense peptide biomarkers of diseases such as diabetes, neurodegeneracy, and ovarian cancer has been demonstrated, the challenge of achieving biomarker detection at clinical concentrations remains. In this work, we sought to reduce the limit of detection of this approach through the modification of the gold clusters and the consideration of non-cluster methods of enhancing peptide dwell times, such as the introduction of small thiol dimers. By achieving a lower detection limit, a wider range of critical diagnostic applications become practically possible using nanopore sensing.