Bone regeneration is entangled with complex physiological processes by numerous biomaterials since they should be stable and immune-compatible with the body. Calcium phosphate (CaP)-based bioceramics have emerged as promising biomaterials for bone tissue engineering applications due to their chemical similarity with inorganic part of native human bone. Among them, calcium phosphate cements (CPC) are biomaterials highlighted by their osteoconductivity, osteoinduction capacity, easy to set at environment temperatures with a low exothermic reaction, moldable and potentially injectable. Particularly, apatite CPC can be developed at suitable pH values, being an attractive option to be used as a carrier for protein-derived growth factors. Platelet lysates (PL) are cell-free, protein- and growth factors-rich biological materials that can substantially boost cell growth and proliferation. In this sense, the incorporation of PL in CPC could be a promising solution to improve their bioactivity.
 
The present work aims to develop apatite-based CPC containing PL. High purity alpha-tricalcium phosphate (α-TCP) powders with optimized particle size distribution were synthesised and used as raw-material. CPC pastes were prepared by mixing α-TCP powder with deionized water in a liquid-to-powder ratio of 0.35 g/mL. CPC pastes with different amounts of PL were prepared and characterised by setting times. Crystalline phases, porosity, mechanical performance and in vitro cytotoxicity and cytocompatibility in the presence of MC3T3 cell line of the resultant CPC were also assessed. The results showed that PL were successfully incorporated in the CPC matrix. Moreover, the PL addition influences the setting time and, consequently the crystalline phases formed and the mechanical performance when compared to neat CPC. The produced PL-enriched CPC demonstrated no toxic effects in cell cultures making them promising candidates for bone tissue engineering applications.

Acknowledgments: This study was funded by European Union’s Horizon 2020 research and innovation programme under the scope of InterLynk project with grant agreement No 953169. The project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC) is also acknowledged. P. M. C. Torres and S. M. Olhero acknowledge FCT for CEECIND/01891/2017 and CEECIND/03393/2017 contracts, respectively.