Radial control of recognition and redox processes with multivalent nanoparticle hosts

Area of Science:

• Supramolecular Chemistry
• Nanotechnology
• Biophysical Chemistry

Background:

• Mixed Monolayer Protected Gold Clusters (MMPCs) offer tunable host-guest chemistry.
• Flavins are essential biological cofactors with redox activity.
• Multivalent host-guest systems are crucial for molecular recognition and sensing.

Purpose of the Study:

• To investigate the multivalent binding of flavins to MMPCs.
• To explore the influence of host structure and flavin redox state on binding affinity.
• To establish MMPCs as models for enzymatic recognition and platforms for device fabrication.

Main Methods:

• Synthesis of MMPCs with varying side chain lengths and recognition functionalities (hydrogen bonding, aromatic stacking).
• Spectroscopic and electrochemical techniques to study flavin binding and redox properties.
• Computational modeling to understand host-guest interactions and preorganization effects.

Main Results:

• MMPCs effectively bind flavins through multivalent interactions.
• Binding affinity exhibits a strong radial dependence, enhanced by proximity to the MMPC surface (approx. 3-fold increase).
• The effect of preorganization is reversed upon flavin reduction, with longer MMPC side chains showing stronger binding (approx. 7-fold increase) due to dipolar interactions.

Conclusions:

• Host structure and flavin redox state critically modulate recognition and binding.
• MMPCs provide a tunable platform for controlling host-guest interactions, mimicking enzymatic systems.
• These findings facilitate the design of advanced molecular recognition tools and functional nanomaterials.