[1] Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Cambridge, MA 02138 USA
[2] Harvard Univ, Wyss Inst Biologically Inspired Engn, Cambridge, MA 02138 USA
[3] MIT, Elect Res Lab, 77 Massachusetts Ave, Cambridge, MA 02139 USA
[4] MIT, Dept Mech Engn, 77 Massachusetts Ave, Cambridge, MA 02139 USA
[5] Harvard MIT Div Hlth Sci & Technol, 77 Massachusetts Ave, Cambridge, MA 02139 USA
[6] ETH, Winterthurerstr 190, CH-8057 Zurich, Switzerland