Functional characterization of a supramolecular affinity switch at the single molecule level

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Nanotechnology

Background:

• Resorcinarene molecules are versatile hosts for guest molecules.
• Controlling supramolecular host-guest interactions is crucial for developing smart materials.
• Photodimerizable moieties offer a route to externally switchable molecular systems.

Purpose of the Study:

• To quantitatively investigate surface-immobilized, switchable resorcinarene receptors.
• To explore the effect of photodimerization on receptor structure and binding affinity.
• To establish a link between structural changes and binding properties at the single-molecule level.

Main Methods:

• Atomic Force Microscopy (AFM) for topographic imaging.
• AFM-Single Molecule Force Spectroscopy (AFM-SMFS) for measuring binding forces.
• Photochemical switching using ultraviolet (UV) light and thermal stimuli.

Main Results:

• Successfully immobilized and characterized switchable resorcinarene receptors.
• Demonstrated external control over receptor conformation and binding affinity using UV light and heat.
• Quantified changes in complexation affinity for ammonium guest ions correlating with structural alterations.

Conclusions:

• The study confirms the feasibility of externally controlling supramolecular receptor affinity.
• Single-molecule force spectroscopy provides a powerful tool to associate binding properties with structural changes.
• This work lays the foundation for designing responsive supramolecular materials with tunable recognition properties.