Uniform double-walled polymer microspheres of controllable shell thickness

Area of Science:

• Biomaterials Engineering
• Nanotechnology
• Drug Delivery Systems

Background:

• Fabricating uniform microspheres is crucial for controlled release applications.
• Previous methods lacked precise control over shell thickness and core encapsulation.
• Developing double-walled microspheres offers enhanced encapsulation and release profiles.

Purpose of the Study:

• To develop a method for fabricating uniform double-walled microspheres with controllable size and shell thickness.
• To investigate the encapsulation of different biodegradable polymers within these double-walled structures.
• To demonstrate the tunability of shell thickness for tailored drug delivery.

Main Methods:

• Utilized multiple concentric nozzles to create a coaxial jet of shell and core materials.
• Employed acoustic excitation to break the coaxial jet into uniform core-shell droplets.
• Controlled jet orientation, material flow rates, and solvent extraction for precise fabrication.
• Fabricated double-walled microspheres using bulk-eroding poly(D,L-lactide-co-glycolide) (PLG) and surface-eroding poly[(1,6-bis-carboxyphenoxy) hexane] (PCPH).

Main Results:

• Achieved uniform and well-centered double-walled microspheres with controllable shell thickness.
• Demonstrated complete encapsulation of core materials by the shell phase.
• Successfully formed poly[(1,6-bis-carboxyphenoxy) hexane] shells encapsulating poly(D,L-lactide-co-glycolide) cores.
• Varied shell thickness from sub-micron to tens of microns for microspheres around 50 micrometers in diameter.

Conclusions:

• The developed method provides precise control over double-walled microsphere fabrication.
• This technology enables the creation of tailored microstructures for advanced drug delivery.
• The ability to control shell thickness and ensure complete encapsulation opens new possibilities in biomaterial design.