Combined Effect of Pulsed Electromagnetic Field and Sound Wave on In Vitro and In Vivo Neural Differentiation of Human Mesenchymal Stem Cells Yun-Kyong Choi Dept. of Medical Biotechnology, Dongguk University, Seoul, Korea Enerelt Urnukhsaikhan Dept. of Medical Biotechnology, Dongguk University, Seoul, Korea Hee-Hoon Yoon Dongguk University Research Inst. of Biotechnology, Seoul, Korea Young-Kwon Seo Dept. of Medical Biotechnology, Dongguk University, Seoul, Korea Hyunjin Cho Dongguk University Research Inst. of Biotechnology, Seoul, Korea Jong-Seob Jeong Dept. of Medical Biotechnology, Dongguk University, Seoul, Korea Soo-Chan Kim Graduate School of Bio and Information Technology, Hankyong National University, Anseong-si, Kyonggi-do, Korea Jung-Keug Park Dept. of Medical Biotechnology, Dongguk University, Seoul, Korea DOI 10.1002/btpr.2389 Published online November 18, 2016 in Wiley Online Library (wileyonlinelibrary.com) Biophysical wave stimulus has been used as an effective tool to promote cellular maturation and differentiation in the construction of engineered tissue. Pulsed electromagnetic fields (PEMFs) and sound waves have been selected as effective stimuli that can promote neural differentiation. The aim of this study was to investigate the synergistic effect of PEMFs and sound waves on the neural differentiation potential in vitro and in vivo using human bone marrow mesenchymal stem cells (hBM–MSCs). In vitro, neural-related genes in hBM–MSCs were accelerated by the combined exposure to both waves more than by individual exposure to PEMFs or sound waves. The combined wave also up-regulated the expression of neural and synaptic-related proteins in a three-dimensional (3-D) culture system through the phos- phorylation of extracellular signal-related kinase. In a mouse model of photochemically induced ischemia, exposure to the combined wave reduced the infarction volume and improved post-injury behavioral activity. These results indicate that a combined stimulus of biophysical waves, PEMFs and sound can enhance and possibly affect the differentiation of MSCs into neural cells. Our study is meaningful for highlighting the potential of combined wave for neurogenic effects and providing new therapeutic approaches for neural cell therapy. V C 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:201–211, 2017 Keywords: pulsed electromagnetic fields, sound wave, combined stimulus, neural differentia- tion, human bone marrow mesenchymal stem cells Introduction Wave energy has been a particular focus of scientific research as a new therapy to influence living organisms. Physical wave forces induce many biological responses in humans at different levels, which coincide with cellular effects including proliferation, differentiation, and gene/pro- tein expression. 1,2 Various biological systems respond to endogenous and exogenous physical wave factors including vibration, magnetic fields, electric fields, radiation, and sound. 3 Electromagnetic fields (EMFs) and sound waves are popular factors that are known to stimulate cell functions by exerting a force on the cells and on the extracellular matrix (ECM). 4,5 EMFs have been reported to induce various cellular/ molecular responses and to enhance cell proliferation and This article was published online on 17 November 2016. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected on 21 December 2016. Correspondence concerning this article should be addressed to J.-K. Park at jkpark@dongguk.edu V C 2016 American Institute of Chemical Engineers 201