Single-molecule analysis of the self-assembly process facilitated by host-guest interactions

Area of Science:

• Supramolecular Chemistry
• Nanotechnology
• Analytical Chemistry

Background:

• Host-guest complex formation is fundamental in supramolecular chemistry.
• Understanding self-assembly dynamics at the molecular level is challenging.
• Para-sulfonatocalix[6]arenes (SC6) and methyl viologen (MV2+) are model systems for host-guest interactions.

Purpose of the Study:

• To analyze the self-assembly process of SC6 and MV2+ complexes at the single-molecule level.
• To discriminate between different stoichiometry complexes (1:1 and 1:2) in real time.
• To demonstrate the utility of nanopore sensing for studying supramolecular assembly.

Main Methods:

• Utilized an α-hemolysin nanopore for single-molecule analysis.
• Monitored ionic current changes through the nanopore as molecules translocated.
• Analyzed translocation events to identify and differentiate SC6-MV2+ complex stoichiometries.

Main Results:

• Successfully discriminated between 1:1 and 1:2 SC6-MV2+ complexes.
• Observed the self-assembly process in real time within the nanopore.
• Demonstrated distinct nanopore signal patterns corresponding to different complex structures.

Conclusions:

• Single-molecule analysis using nanopores is a powerful tool for studying host-guest complex self-assembly.
• The method allows for real-time discrimination of molecular complex stoichiometries.
• This approach provides insights into the dynamics of supramolecular assembly processes.