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Preparation of Calcium Alginate Nanoparticles Using Water-in-Oil (W/O) Nanoemulsions
journal contribution
posted on 2012-03-06, 00:00 authored by Alexandra H. E. Machado, Dan Lundberg, António J. Ribeiro, Francisco J. Veiga, Björn Lindman, Maria G. Miguel, Ulf OlssonA 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 (C12E4), 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 CaCl2 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.