Division of Applied Mathematics, Brown University, Providence, Rhode Island, United States of America.|Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.|Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.|Department of Biomedical Engineering, Computational Biology Department, and Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America.|Division of Applied Mathematics, Brown University, Providence, Rhode Island, United States of America.