Abstract: BACKGROUND: Bone tissue engineering scaffolds with modified growth factors have promising applications in bone repair materials, but the rapid release of growth factors leads to composite scaffolds that can promote bone repair only at an early stage, and the coating process provides a new idea to solve this problem.
OBJECTIVE: To prepare Mg-F membrane/icaritin/β-tricalcium phosphate scaffold to characterize the biological properties of the new scaffold.  
METHODS: The β-tricalcium phosphate scaffold was prepared by applying 3D printing technology, and the icaritin/β-tricalcium phosphate scaffold was prepared by low energy electron beam deposition technology. Mg-F membrane/icaritin/β-tricalcium phosphate scaffolds were fabricated by pulsed laser deposition technology. The microstructure, pore diameter, porosity, wire diameter, compressive strength, and elemental composition of the scaffolds were examined, and the icaritin binding force and slow-release properties were analyzed. Rabbit bone marrow mesenchymal stem cells were co-cultured with β-tricalcium phosphate scaffold, icariin/β-tricalcium phosphate scaffold and Mg-F membrane/icariin membrane/β-tricalcium phosphate scaffold extract. Cell proliferation was measured by CCK8 assay. Rabbit bone marrow mesenchymal stem cells were co-cultured with the above three scaffolds, separately, and osteogenic induction medium was added, and the osteogenic differentiation ability was observed by alizarin red staining.
RESULTS AND CONCLUSION: (1) Scanning electron microscope showed that the structure of β-tricalcium phosphate scaffold was relatively regular and the pore connectivity rate was good; the surface of the icariin membrane/β-tricalcium phosphate scaffold had relatively dense icariin membrane covering the original microscopic pores; Mg-F membrane was deposited on the surface of the icariin membrane, leaving a relatively rough and loose surface with microscopic pores. The differences in pore diameter, porosity, wire diameter, and compressive strength of three kinds of scaffolds were not statistically significant (P > 0.05). (2) The icariin binding force of Mg-F membrane /icariin membrane /β-tricalcium phosphate scaffold was better than that of icariin membrane /β-tricalcium phosphate scaffold (P < 0.05), and slow release of icariin lasted longer. (3) The results of CCK8 assay showed that the three kinds of scaffold extracts did not affect the growth of bone marrow mesenchymal stem cells. Alizarin red staining showed that at 21 days of osteogenic induction, the number of calcium nodules and the maturity of calcium nodules in the Mg-F membrane/icariin membrane/β-tricalcium phosphate scaffold group and the icariin membrane/β-tricalcium phosphate scaffold group were better than those in the β-tricalcium phosphate scaffold group. (4) The results show that the Mg-F membrane/ icariin membrane / β-tricalcium phosphate scaffold has good cytocompatibility, osteogenic ability, drug binding and sustained release properties. 

Key words: pulsed laser deposition, low energy electron beam, sustained-release membrane, β-tricalcium phosphate, bone tissue engineering scaffold, icaritin