**4.5 Conjugated alginate potential as drug-delivery system**

Due to the relative feasibility of conjugation and semi-permeable wall structure of alginate microcapsules shows promising secretory capabilities for robust nanoparticle drug-delivery systems [8, 84–86]. Recently researchers have been able to conjugate alginate microcapsules with anti-HIV zidovudine nanoparticles. Results showed significant improvements in internalization of the nanoparticle into glioma cells during *in vitro* experiments marking for potential use as a targeted viral drug delivery system [87]. Another study demonstrated the conjugation of sodium alginate with graphene oxide which is known to create functional groups for synthesis. GO-conjugated alginate hydrogels readily loaded the anticancer drug oxorubicin hydrochloride (DOX·HCl) and caused high cytotoxicity when exposed to immortal HeLa cell lines [88]. When islet containing alginate microcapsules were conjugated with VEGF, increases in angiogenesis, islet viability, and islet function were observed [89]. More recently, similar benefits were observed through increases in bone formation and blood vessel growth after biomineral-conjugated alginate microcapsules containing MSCs were transplanted into sheep with ovine iliac crest bone defects [90]. The versatile conjugation behavior of alginate hydrogels has impressive potential for a variety of future medical applications in transplantation.
