Stem cell migration and mechanotransduction on linear stiffness gradient hydrogels

William J. Hadden, Jennifer L. Young, Andrew W. Holle, Meg L. McFetridge, Du Yong Kim, Philip Wijesinghe, Hermes Taylor-Weiner, Jessica H. Wen, Andrew R. Lee, Karen Bieback, Ba Ngu Vo, David D. Sampson, Brendan F. Kennedy, Joachim P. Spatz, Adam J. Engler, Yu Suk Cho^*