Single-molecule sensing with an anthrax nanopore enabled by pH-asymmetric ionic liquids

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Anthrax protective antigen forms a heptameric channel with nanopore properties.
• Instability issues like current attenuation and occlusion limit its use in single-molecule sensing.

Purpose of the Study:

• To stabilize the anthrax nanopore for improved single-molecule sensing.
• To investigate the effect of different electrolyte systems on nanopore stability and electrical properties.

Main Methods:

• Designed four electrolyte systems: KCl, NaCl, LiCl, and 1-butyl-3-methylimidazolium chloride ([BMIM]Cl).
• Applied asymmetric ionic strength and pH conditions.
• Evaluated nanopore stability, electrical characteristics, and molecular detection capabilities.

Main Results:

• The [BMIM]Cl system with pH asymmetry significantly stabilized the nanopore.
• Achieved diminished channel occlusion, enhanced signal-to-noise ratio, and steady open-pore current.
• Demonstrated single-molecule discrimination of MAPKK gene family peptides.

Conclusions:

• Ionic liquids, specifically [BMIM]Cl, can create a robust nanopore platform for high-resolution sensing.
• This stabilized nanopore platform offers advantages for detecting biologically relevant molecules.
• Highlights the potential of ionic liquids in regulating nanoscale transport for biosensing applications.