Probing exchange pathways in one-dimensional aggregates with super-resolution microscopy.

Area of Science:

• Supramolecular chemistry and materials science.
• Biophysics and molecular biology.

Background:

• Supramolecular fibers are essential structural components in both biological systems and synthetic materials.
• Understanding molecular dynamics, such as monomer exchange, is crucial for controlling fiber properties and functions.
• Previous ensemble measurements lacked the resolution to reveal detailed molecular exchange mechanisms.

Purpose of the Study:

• To quantitatively investigate molecular exchange pathways in supramolecular fibers.
• To develop and demonstrate a methodology combining super-resolution microscopy and stochastic simulation for studying single aggregates.
• To elucidate the mechanism of monomer exchange in self-assembled supramolecular fibrils.

Main Methods:

• Employed super-resolution stochastic optical reconstruction microscopy (STORM) to visualize individual supramolecular fibers at high resolution.
• Utilized stochastic simulation to model and analyze molecular dynamics and exchange processes.
• Applied the combined methodology to synthetic building blocks that self-assemble into supramolecular fibrils.

Main Results:

• Revealed a homogeneous molecular exchange pathway along the entire polymer backbone of supramolecular fibers.
• Demonstrated that single-aggregate studies provide a detailed molecular picture hidden by previous ensemble measurements.
• Validated the potential of the combined STORM and simulation approach for analyzing molecular exchange.

Conclusions:

• The study provides a quantitative understanding of monomer exchange dynamics in supramolecular fibers.
• The developed methodology enables detailed investigation of structure-dynamics relationships in one-dimensional aggregates.
• These findings open new avenues for studying both synthetic and natural supramolecular fiber systems.