Preparation of Template-Free Robust Yolk-Shell Gelled Particles from Controllably Evolved All-in-Water Emulsions

Area of Science:

• Materials Science
• Chemical Engineering
• Biotechnology

Background:

• Developing novel microencapsulation techniques is crucial for advancements in drug delivery and synthetic biology.
• Current methods often require templates or organic solvents, limiting their applicability and environmental impact.

Purpose of the Study:

• To report a template-free, all-aqueous method for preparing robust hollow capsules with gelatin shells.
• To investigate the formation and properties of these capsules from double emulsions.

Main Methods:

• Utilizing a quaternary system of water/polyethylene glycol (PEG)/gelatin/alginate at elevated temperatures (>40 °C).
• Inducing the spontaneous formation of PEG-in-gelatin-in-PEG double emulsion droplets with multinuclear cores.
• Controlling capsule formation by manipulating temperature relative to gelatin's gelling point.

Main Results:

• Double emulsion droplets remained stable upon cooling after gelatin gelled.
• Above gelatin's melting temperature, droplets transformed into stable mononuclear yolk-shell capsules.
• The gelatin shell demonstrated capacity for incorporating latex beads and reinforcement with glutaraldehyde or silica.

Conclusions:

• This all-aqueous, template-free approach provides a scalable method for producing hollow gelatin capsules.
• The demonstrated payload encapsulation capabilities highlight potential applications in microencapsulation and drug delivery systems.