Hierarchically structured nanocomposites comprising levels from the macroscopic tissue arrangement down to the molecular arrangement of proteins have a great potential in tissue engineering and regenerative medicine. The nanoscale of the materials can provide a dramatic improvement in the mechanical performance and in the transduction of the mechanical stimuli to the cellular level.¹ Innovative bioceramics-biopolymer nanocomposites are able to bolster scientific efforts for tissue regeneration because of the excellent combination of bioactivity and osteoconductivity of the bioceramics, and the flexibility and shape controllability of the biopolymers. Furthermore, the incorporation of different ions (e.g. strontium, zinc, magnesium, manganese, silicon) into the nanocomposites showed an ionic released during bone graft resorption, and hence an influence in bone health, while strengthening the mechanical properties of the implants.² Besides, minerals and traces of metal elements may provide physicochemical modifications in the produced materials, which can accelerate bone formation and resorption in vivo.¹ In this study, we aim to evaluate calcium phosphates-based nanocomposites doped with Zn, Sr, and Mn, towards tissue regeneration. Outcomes showed that incorporating metal ions, such as Zn, Sr, and Mn, into the composites, can increase crystallinity, solubility, and mechanical strength. The biological performance of human adipose derived stem cells (hASCs) presented different responses on cell proliferation/differentiation with the incorporation of different ions. hASCs were induced to differentiate toward a osteogenic phenotype by culturing onto the ions coated structures as demonstrated by ALP activity and alizarin red staining. Proliferation is stimulated when Zn is incorporated, while Sr and Mn showed greater osteogenic potential.² Besides, combining these bioceramics with enzymatically crosslinked silk fibroin resulted in boosted physicochemical, mechanical and biological performance, being a viable strategy for osteochondral regeneration.³ Co-cultured cells adhered and proliferated onto the hierarchical scaffolds, showing a mineralized ECM and GAGs deposition in bone and cartilage-like layers, respectively.

References

1. S Pina, JM Oliveira, RL Reis, Advanced Materials 2015;27: 1143–1169.

2. S Pina, RF Canadas, G Jiménez, Cells Tissues Organs 2017;204:150.

3. S.Pina, V Ribeiro, RL Reis, JM Oliveira, Patent Application no. 110106 N, 2017.

Acknowledgments: The authors thank to the project FROnTHERA (NORTE-01-0145-FEDER-000023), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). The financial support from the Portuguese Foundation for Science and Technology to M-ERA-NET/0001/2014 project and to the funds provided under the program Investigador FCT (IF/01285/2015) are also greatly acknowledge.