title: Preparation of calcium alginate nanoparticles using water-in-oil (W/O) nanoemulsions.
abstract: A procedure for the preparation of calcium alginate nanoparticles in the aqueous phase of water-in-oil (W/O) nanoemulsions was developed. The emulsions were produced from mixtures of the nonionic surfactant tetraethylene glycol monododecyl ether (C(12)E(4)), decane, and aqueous solutions of up to 2 wt % sodium alginate by means of the phase inversion temperature (PIT) emulsification method. This method allows the preparation of finely dispersed emulsions without a large input of mechanical energy. With alginate concentrations of 1-2 wt % in the aqueous phase, emulsions showed good stability against Ostwald ripening and narrow, monomodal distributions of droplets with radii <100 nm. Gelation of the alginate was induced by the addition of aqueous CaCl(2) to the emulsions under stirring, and particles formed were collected using a simple procedure based on extraction of the surfactant on addition of excess oil. The final particles were characterized using cryo-transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). They were found to be essentially spherical with a homogeneous interior, and their size was similar to that of the initial emulsion droplets. The herein presented "low-energy" method for preparation of biocompatible nanoparticles has the potential to be used in various applications, e.g., for the encapsulation of sensitive biomacromolecules.
authors.affiliation: Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, Lund, Sweden. alexandra.machado@fkem1.lu.se
authors.forename: Alexandra H E
authors.initials: AH
authors.lastname: Machado
authors.forename: Dan
authors.initials: D
authors.lastname: Lundberg
authors.forename: António J
authors.initials: AJ
authors.lastname: Ribeiro
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Veiga
authors.forename: Björn
authors.initials: B
authors.lastname: Lindman
authors.forename: Maria G
authors.initials: MG
authors.lastname: Miguel
authors.forename: Ulf
authors.initials: U
authors.lastname: Olsson
mesh_terms: D000464:Alginates / Q000737:chemistry*; D020285:Cryoelectron Microscopy; D004655:Emulsions / Q000737:chemistry*; D005027:Ethylene Oxide / Q000737:chemistry; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009821:Oils / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000464:Alginates; D004655:Emulsions; D006603:Hexuronic Acids; D009821:Oils; D013501:Surface-Active Agents; D014867:Water; D020723:Glucuronic Acid; D005027:Ethylene Oxide