Magnesium scaffolds with two novel biomimetic designs and MgF2 coating for bone tissue engineering

Abstract

In this study, magnesium scaffolds including 60% porosity were designed and fabricated using sucrose spacer agent by the powder metallurgy technique with the pore size of 400–600 μm with two biomimetic designs of the filled center design (FCD) and the hollow center design (HCD) for bone regeneration. The spacer agent was removed by distilled water and hydrofluoric (HF) acid before the sintering process. After the sintering process, on the surfaces of both scaffold designs, magnesium fluoride (MgF2) coating was applied. Evaluation of scaffolds by X-ray diffractometery (XRD) show that, on the surface of the untreated scaffolds MgF2 had been negligible formed because of spacer agent removal process using HF solution. However, on the surface coated magnesium scaffold a thicker coating of MgF2was formed. Results of compression test showed that by changing the design from hollow center to filled, the yield stress of the scaffolds increased from 7.3 MPa to 22 MPa. In addition, in vitro test indicated that both designs of MgF2 coated magnesium scaffolds had approximately same degradation rates. Also, the results of magnesium ion release by ICP-AES test showed that the MgF2 coated magnesium scaffolds had lower degradation rate compared to uncoated scaffolds. In addition, EDS analysis on the surface of the coated magnesium scaffold confirms the formation of MgF2 coating. Also, this analysis showed that after 14 days of immersion in Dullbecco's PBS solution, the MgF2 layer remained on the surface of the scaffold.