1. School of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325, USA
2. Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, Illinois 60208, USA
3. Evolution and Optics of Nanostructures Group, Department of Biology, Ghent University, Ledeganckstraat 35, Ghent 9000, Belgium
4. Department of Materials Science and Engineering, Department of Biomedical Engineering, Department of Pharmacology, Northwestern University, Evanston, Illinois 60208, USA