SiNWs Biophysically Regulate the Fates of Human Mesenchymal Stem Cells.

While biophysical stimuli from polymeric matrices are known to significantly affect the fates of human mesenchymal stem cells (hMSCs), the stimulatory effects of nano-sized silicon-based matrices on hMSCs have not been thoroughly investigated. We previously demonstrated that vertically aligned, single-crystalline silicon nanowires (SiNWs) can control the osteogenicity of hMSCs via controllable spring constants from SiNWs matrix. However, other possible differentiation fates of hMSCs on SiNWs have not been explored. We hypothesize that tunable spring constant from artificial SiNWs matrices can direct different types of hMSC differentiations. The spring constants of tunable SiNW matrices can be consistently controlled by tuning the SiNW length. The results of gene expression and cell stiffness suggest that hMSCs differentiations are sensitive to our distinguishable spring constants from the SiNWs groups, and simultaneously conduct osteogenicity and adipogenicity. These findings suggest that SiNW matrices can regulate the fates of hMSCs when the SiNW characteristics are carefully tuned.