Emulsion templating of poly(lactic acid) particles: droplet formation behavior

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Poly(DL-lactic acid) (PLA) is a biodegradable polymer with applications in drug delivery and tissue engineering.
• Fabrication of monodisperse microparticles is crucial for controlled release and consistent material properties.
• Flow focusing microfluidic devices offer precise control over droplet generation and particle formation.

Purpose of the Study:

• To develop a method for fabricating monodisperse poly(DL-lactic acid) (PLA) microparticles.
• To investigate the influence of flow rates and device geometry on droplet and particle size.
• To characterize the porosity of the resulting PLA particles.

Main Methods:

• Utilized flow focusing glass microcapillary devices for particle fabrication.
• Employed an emulsion-based method with dichloromethane (DCM) as the dispersed phase and poly(vinyl alcohol) (PVA) as the continuous phase.
• Controlled particle formation through solvent evaporation at room temperature.

Main Results:

• Achieved monodisperse PLA particles (11-121 μm) with low porosity (particle diameter 2.7 times smaller than droplet template).
• Identified the dripping regime as essential for producing uniform droplets (CV < 2%) with specific flow rate ratios (4-25).
• Observed polydisperse droplets (CV > 6%) under jetting regime conditions.

Conclusions:

• Flow focusing microfluidics enables precise fabrication of monodisperse, low-porosity PLA microparticles.
• Optimized dripping regime parameters are critical for achieving high uniformity in droplet and subsequent particle generation.
• The study provides a scalable method for producing well-defined PLA microparticles for various applications.