Controlling polymersome size through microfluidic-assisted self-assembly: Enabling 'ready to use' formulations for...

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Polymersomes, self-assembled vesicles from block copolymers like PEG-b-PTMC, are promising nanocarriers.
• Their preparation often requires solvent exchange, which can affect stability for biological use.
• Microfluidic systems offer controlled environments for nanoparticle formation.

Purpose of the Study:

• To evaluate the self-assembly of PEG-b-PTMC into polymersomes using microfluidic systems.
• To develop a method for preparing polymersomes directly in aqueous media suitable for biological applications.
• To investigate the influence of microfluidic parameters on polymersome size and formation.

Main Methods:

• Utilized two microfluidic chips (micromixer and Herringbone) for solvent displacement.
• Employed a solvent exchange method from DMSO to aqueous media (300 mOsm L⁻¹).
• Characterized the resulting nanoparticles using multi-angle light scattering and cryo-Transmission Electron Microscopy (cryo-TEM).

Main Results:

• Polymersome formation was achieved using microfluidic solvent displacement.
• The organic/aqueous solvent ratio did not affect vesicle size.
• Total flow rate and copolymer concentration influenced polymersome diameter, yielding sizes from 76 nm to 224 nm.
• Successful preparation in isotonic aqueous media was demonstrated.

Conclusions:

• Microfluidics provides a controlled method for PEG-b-PTMC polymersome synthesis.
• The developed solvent exchange protocol enables direct use of polymersomes in biological media.
• Process parameters like flow rate and concentration are critical for controlling polymersome size.