Background:Three-dimensional (3D) printing technology holds great promise for treating diseases or injuries that affect human bones with enhanced performance over traditional techniques.Different patts of design can lead to various mechanical properties and biocompatibility to various degrees.However,there is still a long way to go before we can fully take advantage of 3D printing technologies.Methods:This study tailored 3D printed scaffolds with gelatin and platelets to maximize bone regeneration.The scaffolds were designed with special intal porous structures that can allow bone tissue and large molecules to infiltrate better into the scaffolds.They were then treated with gelatin and platelets via thermo-crosslinking and freeze-drying,respectively.Vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-β1 were measured at different time points after the scaffolds had been made.Cell proliferation and cytotoxicity were determined via cell counting kit-8 (CCK-8) assay.Results:There was a massive boost in the level of VEGF and TGF-β1 released by the scaffolds with gelatin and platelets compared to that of scaffolds with only gelatin.After 21 days of culture,the CCK-8 cell counts of the control group and treated group were significantly higher than that of the blank group (P ＜ 0.05).The cytotoxicity test also indicated the safety of the scaffolds.Conclusions:Our experiments confirmed that the 3D printed scaffolds we had designed could provide a sustained-release effect for growth factors and improve the proliferation of preosteoblasts with little cytotoxicity in vitro.They may hold promise as bone graft substitute materials in the future.