Droplet shape control using microfluidics and designer biosurfactants.

Area of Science:

• Materials Science
• Biomaterials Engineering
• Colloid and Surface Chemistry

Background:

• Precise control over emulsion droplet size and shape is crucial for many applications.
• Existing methods often struggle with long-term shape stability and precise control.
• Protein-surfactants offer potential for stabilizing emulsions, but shape memory remains a challenge.

Purpose of the Study:

• To develop a 'shape-memorable' micro-droplet formulation with enhanced stability and shape control.
• To investigate the role of polyethylene glycol (PEG)-modified proteins in droplet stabilization and shape retention.
• To explore the potential of these functionalized droplets for biomimetic applications.

Main Methods:

• Synthesis of monodisperse micro-droplets using a flow-focusing microfluidic device.
• Formulation of droplets stabilized by polyethylene glycol (PEG)-modified protein-surfactants.
• Characterization of interfacial protein network mechanical properties and PEG layer influence.
• Demonstration of droplet interface functionalization with accessible biotins.

Main Results:

• Droplets exhibited stability against coalescence for months and maintained non-spherical shapes for hours.
• Controllable synthesis of monodisperse droplets with aspect ratios from 1.0 to 3.4 was achieved.
• PEGylation of protein-surfactants enhanced interfacial network strength, enabling shape conservation.
• Functionalization of droplet interfaces with biotins was successfully demonstrated.

Conclusions:

• Polyethylene glycol (PEG)-modified protein-surfactants create robust, shape-memorable micro-droplets.
• The enhanced interfacial properties allow for prolonged non-spherical droplet stability.
• These findings offer a tailorable interface for diverse biomimetic and functional applications.