Alginate microbeads with internal microvoids for the sustained release of drugs

The process of Ca²⁺ mediated gelation of alginate and the fabrication of nanoengineered polyelectrolyte capsules were combined for the preparation of alginate microbeads characterized by the presence of well-defined drug loaded microvoids in their volume. The obtained engineered alginate microbeads are described in terms of their morphology, loading efficiency and release characteristics. It was found that the generation of microvoids in the volume of alginate microbeads could be a promising approach for the creation of microstructured and biocompatible hydrogels, prospectively having highly tunable properties in terms of loading and releasing characteristics. In particular, it was found that the developed system was able to limit drug leakage during the gelation process and to control the initial burst release of small hydrophilic drug molecules, such as doxorubicin hydrochloride. Finally, the cytocompatibility of the developed microhydrogels was assessed on MCF-7 human breast cancer cells as well as their ability to sustain the release of the model drug during time.