[1] ETH, Dept Hlth Sci & Technol, LFO, CH-8092 Zurich, Switzerland
[2] ETH, Dept Hlth Sci & Technol, HPL, CH-8093 Zurich, Switzerland
[3] McGill Univ, Biointerface Lab, Dept Min & Mat Engn, Montreal, PQ H3A 0C5, Canada
[4] ETH, Dept Mat, CH-8093 Zurich, Switzerland