(164e) Synthesis of Calcium Alginate Gel Beads by Electrodispersion in Vegetable Oil

Micron-size calcium-crosslinked alginate gel beads with high porosity and uniform structure are synthesized for potential application in controlled drug delivery. An electric field is used to atomize alginate and nanocalcium carbonate aqueous mixtures from a nozzle into an organic continuous phase. The crosslinking polymerization takes place in the dispersed droplets, which serve as microreactors. Acetic acid, in the organic phase, diffuses into the microreactor droplets initiating the release of calcium ions and gelation to occur. This technique allows water-in-oil emulsions to be formed and a high fabrication efficiency of spherical gel beads with a mean size of about 20 µm were achieved with a minimum amount of agglomeration. Dependence of the morphology of calcium alginate gel beads on the electric field strength, the concentration of alginate, calcium carbonate and acetic acid and the flow velocity of both phases is assessed. Fluorescence microscopy and scanning election microscopy are used to study the distribution of polymers and particle morphology. As the electrodispersion procedures are easy to perform, this method can also be used for the synthesis of particles and microencapsultion systems from a variety of polymers.