[1] CSIC, Ctr Biol Mol Severo Ochoa, Madrid 28049, Spain
[2] Univ Autonoma Madrid, Madrid 28049, Spain
[3] CSIC CEI UAM CSIC, Inst Micro & Nanotecnol, IMN CNM, Madrid 28760, Spain
[4] Eidgenoss TH ETH Zurich, Dept Biosyst Sci & Engn, CH-4058 Basel, Switzerland