Effect of the guest size and shape on its binding dynamics with sodium cholate aggregates

Area of Science:

• Supramolecular Chemistry
• Physical Chemistry
• Biophysical Chemistry

Background:

• Bile salts, like sodium cholate, form aggregates in aqueous solutions.
• These aggregates can act as host systems for various guest molecules.
• Understanding guest-host interactions is crucial for applications in drug delivery and molecular recognition.

Purpose of the Study:

• To investigate the binding dynamics of hydrophobic guests with sodium cholate aggregates.
• To determine the location and residence time of different guests within the bile salt aggregates.
• To elucidate the role of guest hydrophobicity and molecular structure in aggregate interactions.

Main Methods:

• Laser flash photolysis was employed to study binding kinetics.
• Fluorescence spectroscopy was utilized to probe guest location and environment.
• Analysis of guest-aggregate interactions based on hydrophobicity and molecular dimensions.

Main Results:

• Acenaphthene, phenanthrene, and fluorene (hydrophobic guests) bind to primary sodium cholate aggregates.
• Acenaphthenol (less hydrophobic guest) preferentially binds to secondary bile salt aggregates.
• Guest residence time and accessibility within aggregates are influenced by guest size and shape.

Conclusions:

• Sodium cholate aggregates exhibit adaptable supramolecular host behavior.
• Guest hydrophobicity dictates the binding site within the aggregate structure.
• Aggregate structure and guest properties collectively govern binding dynamics and accessibility.