1. Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 01238, USA.
2. Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA 92521, USA.
3. School of Materials Science and Engineering and School of Biological Sciences, Nanyang Technological University, Singapore 639798.
4. National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973, USA.
5. College of Engineering, Purdue University, West Lafayette, IN 47907, USA.
6. Tescan-USA, Cranberry Township, PA 16066, USA.
7. Biology Department, Gonzaga University, Spokane, WA 99258, USA.