Preparation of Biocompatible Magnetic Colloids From Supercritical Fluid Extraction Of Emulsion
M. Furlan, M. Lattuada, M. Morbidelli, J. Kluge, F. Fusaro, M. Mazzotti
ETH Zurich, CH
Keywords: magnetic nanoparticles, Poly-lactic-co-glycolic acid, sCO2 extraction
Abstract:In this work, we present an innovative and clean process that allows one to prepare submicron monodispersed poly(lactic-co-glycolic) acid (PLGA) particles containing high loads of magnetite nanocrystals. First, magnetite nanocrystals are prepared through the coprecipitation method with ricinoleic acid as capping agent. Then, magnetite nanocrystals and PLGA are first dispersed together in dichloromethane, and subsequently emulsified in water in the presence of polyvinyl alcohol (PVA) as stabilizer. The organic solvent is finally removed by extraction with supercritical carbon dioxide sCO2. This last step is accomplished by spraying the emulsion through a nozzle into a high pressure vessel containing the sCO2. This step can be carried out both in batch or continuous operation modus. The result is a stable suspension of PLGA particles in water with a narrow size distribution. The initial composition of the organic phase determines both the magnetite loading as well as the nanoparticles size, which also depends on the emulsification process. The nanoparticles have been characterized by light scattering as well as both scanning and transmission electron microscopy.