Nanoinclusions in cryogenically quenched nanoemulsions

Area of Science:

• Materials Science
• Physical Chemistry
• Biophysics

Background:

• Understanding the behavior of oil-in-water nanodroplets is crucial for various applications, including drug delivery and materials science.
• The formation of internal structures within nanodroplets during rapid freezing can impact their properties and stability.

Purpose of the Study:

• To investigate the formation of nanoinclusions within silicone oil and squalene nanodroplets dispersed in an aqueous surfactant solution.
• To determine the factors influencing nanoinclusion formation during cryogenic quenching.

Main Methods:

• Dispersion of oil-in-water nanodroplets containing silicone oil and squalene mixtures.
• Rapid quenching of nanodroplets in liquid ethane.
• Examination of frozen samples using cryogenic transmission electron microscopy (CTEM).

Main Results:

• Nanoinclusions were observed within the oil nanodroplets under specific conditions of ice formation and oil composition.
• The formation of these nanoinclusions was independent of the type of surfactant used.
• Observations suggest nanoinclusions originate from vapor cavity nucleation during water freezing.

Conclusions:

• The freezing process of the surrounding aqueous phase can induce the formation of internal nanoinclusions within liquid oil nanodroplets.
• The composition of the oil mixture and the ice phase play critical roles in nanoinclusion formation.
• These findings provide insights into the physical processes occurring at the nanoscale during rapid freezing of emulsions.