title: Microfluidic fabrication of monodisperse polylactide microcapsules with tunable structures through rapid precipitation.
abstract: We describe a versatile and facile route to the continuous production of monodisperse polylactide (PLA) microcapsules with controllable structures. With the combination of microfluidic emulsification, solvent diffusion, and internal phase separation, uniform PLA microcapsules with a perfluorooctyl bromide (PFOB) core were successfully obtained by simply diluting monodisperse ethyl acetate (EA)-in-water emulsion with pure water. Rapid extraction of EA from the droplets into the aqueous phase enabled the solidification of the polymer droplets in a nonequilibrium state during internal phase separation between a concentrated PLA/EA phase and a PFOB phase. Higher-molecular-weight PLA generated structural complexity of the microcapsules, yielding core-shell microcapsules with covered with small PFOB droplets. Removal of the PFOB via freeze drying gave hollow microcapsules with dimpled surfaces. The core-shell ratios and the diameter of these microcapsules could be finely tuned by just adjusting the concentration of PFOB and flow rates on emulsification, respectively. These biocompatible microcapsules with controllable size and structures are potentially applicable in biomedical fields such as drug delivery carriers of many functional molecules.
authors.affiliation: Department of Chemistry and Biotechnology, Graduate School of Natural Science and Technology and ‡Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University , 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Takaichi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Yukitaka
authors.initials: Y
authors.lastname: Kimura
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ono
mesh_terms: D002214:Capsules; D011232:Chemical Precipitation; D004655:Emulsions; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D011091:Polyesters / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D002214:Capsules; D004655:Emulsions; D011091:Polyesters; C033616:poly(lactide)