Monodisperse liquid-filled biodegradable microcapsules.
OBJECTIVE
Encapsulation of liquids into biodegradable polymer microcapsules has been a challenging task due to production limitations stemming from solution viscosity, phase stabilization, molecular localization, and scalable production. We report an extension of Precision Particle Fabrication (PPF) technology for the production of monodisperse liquid-filled microcapsules containing an oil or aqueous core and contrast these results to double-walled microspheres.


METHODS
PPF technology utilizes a coaxial nozzle to produce a liquid core jet surrounded by a polymer annular jet, which is further encompassed by a non-solvent carrier stream, typically 0.5% wt/vol polyvinyl alcohol in water. Jet diameters are controlled by the volumetric flow rate of each phase. The compound jet is then disrupted into uniform core/shell droplets via a controllable acoustic wave and shell material is hardened by solvent extraction.


RESULTS
Monodisperse polymeric microcapsules demonstrated a narrow size distribution and the formation of a continuous shell leading to efficient encapsulation of various liquid cores. The intermingling of core and shell phases and the localization of different molecular probes (fluorescent dyes and fluorescently labeled proteins) to the core or shell phase provided additional evidence of phase separation and molecular partitioning, respectively. We also demonstrate the pulsatile release of bovine serum albumin encapsulated in an aqueous core.


CONCLUSIONS
PPF technology provided exceptional control of the overall size and shell thickness of microcapsules filled with various types of oil or water. This technique may enable advanced delivery profiles of pharmaceuticals or nutraceuticals.
Berkland
Cory
C
Department of Chemical and Petroleum Engineering, 2030 Becker Dr., Lawrence, Kansas 66047, USA. berkland@ku.edu
Pollauf
Emily
E
Varde
Neel
N
Pack
Daniel W
DW
Kim
Kyekyoon Kevin
KK
D000465:Algorithms; D001672:Biocompatible Materials / Q000737:chemistry*; D002214:Capsules / Q000737:chemistry*; D003911:Dextrans / Q000737:chemistry; D004339:Drug Compounding / Q000379:methods*; D045703:Emulsifying Agents / Q000737:chemistry*; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D006586:Hexanes / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry; D008752:Methylene Chloride / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010078:Oxazines / Q000737:chemistry; D010316:Particle Size; D049388:Polyanhydrides / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D011673:Pulsatile Flow; D000074262:Rapeseed Oil; D012235:Rhodamines / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012827:Silicone Oils / Q000737:chemistry; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D014867:Water / Q000737:chemistry
D001672:Biocompatible Materials; D002214:Capsules; D003911:Dextrans; D045703:Emulsifying Agents; D005229:Fatty Acids, Monounsaturated; D005456:Fluorescent Dyes; D006586:Hexanes; D010078:Oxazines; D049388:Polyanhydrides; D011108:Polymers; D000074262:Rapeseed Oil; D012235:Rhodamines; D012827:Silicone Oils; D012996:Solutions; C523504:poly(1,6-bis-4-carboxyphenoxyhexane); D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; C022027:lissamine rhodamine B; D012710:Serum Albumin, Bovine; D019344:Lactic Acid; D008752:Methylene Chloride; C029773:rhodamine B; C044808:nile red