Gelatin methacrylate scaffold for bone tissue engineering: The influence of polymer concentration.

Gelatin methacrylate (GelMA) is an inexpensive, photocrosslinkable, cell-responsive hydrogel which has drawn attention for a wide range of tissue engineering applications. The potential of GelMA scaffolds was demonstrated to be tunable for different tissue engineering (TE) applications through modifying the polymer concentration, methacrylation degree, or UV light intensity. Despite the promising results of GelMA hydrogels in tissue engineering, the influence of polymer concentration for bone tissue engineering (BTE) scaffolds was not established yet. Thus, in this study, we have demonstrated the effect of polymer concentration in GelMA scaffolds on osteogenic differentiation. We prepared GelMA scaffolds with 5 and 10% polymer concentrations and characterized the scaffolds in terms of porosity, pore size, swelling characteristics, and mechanical properties. Subsequent to the scaffolds characterization, the scaffolds were seeded with bone marrow derived rat mesenchymal stem cells and cultured in osteogenic media to evaluate the possible osteogenic differentiation effect exerted by the polymer concentration. After 7, 14, 21, and 28 days, DNA content, calcium deposition, and alkaline phosphatase (ALP) activity of scaffolds were evaluated quantitatively by colorimetric bioassays. Furthermore, the distribution of the calcium deposition within the scaffolds was attained qualitatively and quantitatively by microcomputer tomography (µCT). Our data suggest that GelMA hydrogels prepared with 5% polymer concentration has promoted homogeneous extracellular matrix calcification and it is a great candidate for BTE applications.