The possibility to add different functionalities to scaffolds allows incorporating new properties to guide and promote new bone formation [1, 2]. In this regard, an interesting strategy is to use the scaffold as a delivery system for different agents that play important roles in osteogenesis and angiogenesis to encourage the integration between the biomaterials and the tissue to be regenerated [3, 4]. In this sense, metallic ions such as calcium (Ca2+) and copper (Cu2+) stimulate the promotion of bone formation and vascularization, respectively  contributing to bone formation and regeneration.
The aim of this work was to prepare nanocomposite multifunctional scaffolds with osteogenic, angiogenic and antiresorptive properties, made of alginate crosslinked with calcium or copper ions (Ca2+ or Cu2+) in combination with bioactive glass nanoparticles and alendronate-loaded microparticles.
The scaffolds obtained showed homogeneous structures and a suitable porosity. Moreover, the mechanical properties were evaluated showing that these nanocomposite scaffolds have enough mechanical strength for citocompatibility studies. In addition, the bioactive nature of the scaffolds was confirmed because of the growth of hydroxyapatite crystals on the surface after 14 days in simulated body fluid. The swelling study showed that the novel developed scaffolds have suitable swelling capacity. The degradation study indicated that scaffolds crosslinked with Ca2+ seem to be stable over time showing a slow degradation rate, whereas scaffolds crosslinked with Cu2+ showed a higher degradation rate, which suggests that there might be different interactions between these cations and the alginate chains.
According to the analysis of the release profile of Ca2+, Cu2+ and alendronate from the scaffolds, the values of the amount released were within the ranges reported to promote osteogenesis, angiogenesis and inhibition of bone resorption by osteoclasts, respectively.