Dual ionic crosslinked interpenetrating network of alginate-cellulose beads with enhanced mechanical properties for biocompatible encapsulation

Abstract

Alginate beads have been a popular carrier of a wide array of biologically relevant molecules, such as proteins, genes, and cells, for biomedical applications. However, the difficulty of controlling their mechanical properties as well as maintaining the long-term structural integrity has prevented more widespread utilization. Herein, a simple yet highly efficient method of engineering alginate beads with improved mechanical properties is presented, whereby a secondary network of biocompatible anionic cellulose is created within the alginate network. The aqueous-soluble anionic cellulose, containing either carboxylate or sulfonate, is found to undergo crosslinking reaction with trivalent ions more favorably than divalent ions, necessitating a dual sequential ionic crosslinking scheme to create interpenetrating networks (IPN) of alginate and cellulose with divalent and trivalent ions, respectively. The IPN alginate-cellulose beads demonstrate superior mechanical strength and controllable rigidity as well as enhanced resistance to harsh chemical environment as compared to alginate beads. Furthermore, their suitability for biomedical applications is also demonstrated by encapsulating microbial species to maximize their bioactivity and therapeutic agents for controlled release.