Strain-induced Differentiation of Mesenchymal Stem Cells.

Directing the fate of human mesenchymal stem/stromal cells (hMSCs) toward bone formation using mechanical strain is a promising approach in regenerative medicine related to bone diseases. Numerous studies have evaluated the effects of vibration or cyclic tensile strain on MSCs towards developing a mechanically-based method for stimulating differentiation. Here, we study the differentiation of hMSCs cultured on elastic polydimethylsiloxane (PDMS) membrane, which is magnetically actuated to induce periodically varying strain. The strain distribution across the membrane was calculated by finite-element modeling and demonstrates three main areas of different strain amplitudes. The strain effect on the hMSCs was evaluated by measuring the mineralization of differentiated hMSCs using Alizarin S red stain. The results indicate a strain-dependent differentiation of hMSCs, where the highest region of strain on the membrane resulted in the most accelerated differentiation. Osteogenic differentiation was achieved as early as two weeks, which is significantly sooner than control hMSCs treated with osteogenic media alone.