**4. Conclusions**

The results obtained in this study provide a novel and interesting insight in the field of bioactive glasses for bone regeneration. MBG disks containing 4 or 5% ZnO and decorated with osteostatin were shown to improve osteoblastic cell number as well as osteoblast differentiation capacity. For the first time, osteostatin was demonstrated to enhance the in vitro osteogenic capacity of Zn2+-enriched materials, suggesting the potential of this approach in bone tissue engineering applications.

**Author Contributions:** R.P. and C.H. performed the experiments; S.S.-S. and D.L. supervised the experimental work and wrote the original draft; P.E. and M.V.-R. performed a critical review and revised the publication; A.J.S. organized the financial support, planned the research activity, and supervised the work of the team.

**Funding:** This research was funded by Instituto de Salud Carlos III, gran<sup>t</sup> number PI15/00978 co-financed with the European Union FEDER funds, the European Research Council, Advanced Grant Verdi-Proposal No. 694160 (ERC-2015-AdG) and Ministerio de Economía y Compatitividad (MINECO), gran<sup>t</sup> number MAT2015-64831-R.

**Conflicts of Interest:** The authors declare no conflict of interest.
