Reverse Micelles As Antioxidant Carriers: An Experimental and Molecular Dynamics Study

Area of Science:

• Colloid and Surface Chemistry
• Biophysical Chemistry
• Computational Chemistry

Background:

• Water-in-oil microemulsions offer potential as delivery systems for natural antioxidants.
• Biocompatible surfactants like lecithin and monoglycerides are key components for such formulations.
• Understanding the structure and dynamics of these microemulsions is crucial for optimizing their function.

Purpose of the Study:

• To formulate and characterize water-in-oil microemulsions using biocompatible components.
• To investigate the encapsulation and location of natural antioxidants, hydroxytyrosol (HT) and gallic acid (GA), within the microemulsion.
• To elucidate the structure and thermodynamic stability of reverse micelles (RMs) formed in the system.

Main Methods:

• Dynamic Light Scattering (DLS) and Electron Paramagnetic Resonance (EPR) spectroscopy for experimental characterization.
• Coarse-grained molecular dynamics (CGMD) simulations using the MARTINI force field for computational analysis.
• Formulation of microemulsions using natural surfactants (lecithin, monoglycerides), medium chain triglycerides, and aqueous phase.

Main Results:

• Spontaneous formation and enhanced thermodynamic stability of reverse micelles (RMs) were observed.
• Gallic acid (GA) was localized within the water core, while hydroxytyrosol (HT) was found at the surfactant interfacial layer.
• Computational analysis detailed the distinct molecular locations, explaining experimental observations like RM swelling with GA.

Conclusions:

• Biocompatible microemulsions can effectively encapsulate natural antioxidants.
• The distinct localization of GA and HT within RMs influences microemulsion properties.
• CGMD simulations provide crucial insights into microemulsion structure and dynamics, complementing experimental data.