Magnesium doping on TiN coatings affects mesenchymal stem cell differentiation and proliferation positively in a dose-dependent manner

BACKGROUND: In vitro evaluation of cell-surface interactions for hard tissue implants have mostly been done using osteoblasts. However, when an implant is placed in the body, mesenchymal stem cells (MSCs) play a major role in new bone formation. Therefore, using MSCs in cell-surface investigations may provide more reliable information on the prediction of in vivo behavior of implants. OBJECTIVE: In this study, Mg doped TiN coatings ((Ti,Mg)N) were prepared and tested for their effect on MSC differentiation and mineralization. METHODS: MSCs were isolated from rat bone marrow (rBMSCs) and seeded onto bare Ti, TiN and Mg containing (Ti,Mg)N surfaces. Cell proliferation, osteogenic differentiation (collagen type 1, alkaline phosphatase activity), calcium phosphate deposition (von Kossa staining, Scanning Electron Microscopy) analysis were conducted. RESULTS: Differentiation towards osteoblast lineage was significantly improved with the increment in Mg presence. Collagen type I deposition, mineralization, and the ALP activity were higher on high Mg containing (>10 at% Mg) surfaces but differentiation of rBMSCs were found to be delayed. CONCLUSIONS: Mg presence affected rBMSCs proliferation and differentiation positively in a dose-dependent manner. However, high Mg amounts delayed both proliferation and differentiation.