Revealing the complex self-assembly behaviour of sodium deoxycholate in aqueous solution

Area of Science:

• Biomaterials Science
• Supramolecular Chemistry
• Biophysics

Background:

• Sodium deoxycholate is a natural bile salt with physiological roles and applications as a surfactant.
• Previous models of its self-assembly in water were incomplete and controversial, suggesting missing mesophases.

Purpose of the Study:

• To comprehensively investigate the self-assembly behavior of sodium deoxycholate in aqueous solutions.
• To resolve controversies and complete the understanding of its aggregate structures and phase transitions.

Main Methods:

• Utilized a combination of electron microscopy, optical microscopy, and Small-Angle X-ray Scattering (SAXS).
• Investigated self-assembly under varying conditions of concentration, pH, temperature, and ionic strength/composition.

Main Results:

• Identified novel self-assembled phases including rods, sponges, vesicles, lamellae, and nanotubes.
• Observed reversible transitions among these phases within physiological conditions.
• Integrated findings with existing literature, explaining all structures within established surfactant phase behavior models.

Conclusions:

• Sodium deoxycholate demonstrates exceptional structural variability, forming a wide spectrum of surfactant phases.
• These findings provide fundamental insights into the in vivo functions of bile salts.
• The versatility highlights the molecule's adaptive nature in biological contexts.