Researchers at the University of California, Davis have developed a one-step spray dry calcium cross-linked alginate encapsulation process where the calcium is released from a chelating agent.
Microencapsulation of biological molecules, cells, and chemicals is often used in food and pharmaceutical industries to increase the stability and shelf life of the encapsulated material and to control the pattern of release. Among encapsulation matrices, alginate is preferred due to its low-cost, biodegradability, and biocompatibility. Traditional alginate droplet-calcium bath encapsulation procedures are difficult to scale up and often produce undesirably large alginate beads.
Researchers at the University of California, Davis developed a method for the production of Cross-linked Alginate Microcapsules (CLAMs) using a single step spray drying process which utilizes a calcium chelating agent and volatile base. The reduction in pH with volatilization of the base releases calcium ions from the calcium-chelate complex initiating alginate cross-linking. Particle size is in the range of 5-10 microns and the degree of cross-linking and hence release rate can be controlled by the level of calcium ion introduced. The process is flexible enough to accommodate other anionic polymers. In addition, the process can be modified to produce fibers or films.
* One step spray dry process
Alginate Encapsulation, Spray Drying, Calcium-Mediated Cross-linking