Ionotropic cross-linked polymeric beads for drug delivery and in vitro applications

In recent years, polymer-based beads are emerging as promising platforms for biomedical use, especially in the areas of drug delivery and molecular release in cell culture. Biocompatible polymers from natural sources such as polysaccharides have been variously processed through several methods to produce smart devices with controlled transport properties. For this purpose, ionotropic cross-linking is a high versatile strategy to manufacture stable beads from polyelectrolytes in the presence of ions (i.e., Ca2+, Na+). This approach can be implemented by several process technologies to fabricate microsized beads with controllable size, shape, and good stability. Moreover, ionotropic cross-linked beads also offer the opportunity to introduce functional groups for the development of smart devices with multiple bioactive functions to be used as smart carrier for selective drug delivery. This chapter proposes an overview of the current use of main ionotropic polymers (i.e., alginate, chitosan, gellan gum, etc.) and different technologies recently implemented for the fabrication of beads for drug delivery and in vitro release.