title: Uniform double-walled polymer microspheres of controllable shell thickness.
abstract: A method for fabricating uniform double-walled microspheres with controllable size and shell thickness has been developed. The method, based on previous work to fabricate uniform microspheres, employs multiple concentric nozzles to produce a smooth coaxial jet comprising an annular shell and core material, which is acoustically excited to break up into uniform core-shell droplets. The orientation of the jets, material flow rates, and rate of solvent extraction are controlled to create uniform and well-centered "double-walled" microspheres exhibiting a controllable shell thickness. Double-walled microspheres were fabricated with different arrangements of bulk-eroding poly(D,L-lactide-co-glycolide) (PLG) and surface-eroding poly[(1,6-bis-carboxyphenoxy) hexane] (PCPH). Variation of the fabrication parameters allowed complete encapsulation by the shell phase, including the efficient formation of a PCPH shell encapsulating a PLG core. Utilizing this technology, double-walled microsphere shell thickness can be varied from <2 microm to tens of microns while maintaining complete and well-centered core encapsulation for double-walled microspheres near 50 microm in overall diameter.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801, USA.
authors.forename: Cory
authors.initials: C
authors.lastname: Berkland
authors.forename: Emily
authors.initials: E
authors.lastname: Pollauf
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Pack
authors.forename: Kyekyoon
authors.initials: K
authors.lastname: Kim
mesh_terms: D008863:Microspheres; D011108:Polymers / Q000737:chemistry*; D013678:Technology, Pharmaceutical / Q000295:instrumentation / Q000379:methods*
chemical_list: D011108:Polymers