1. Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, Harvard T. H. Chan School of Public Health, Harvard University, 665 Huntington Avenue, Boston, Massachusetts 02115, United States
2. Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, Connecticut 06504, United States
3. Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Pierce Hall 318, Cambridge, Massachusetts 02138, United States
4. Department of Chemical and Biological Engineering, University of Maine, Orono, Maine 04469, United States
5. School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459, Singapore
6. School of Materials Science and Engineering, Nanyang Technological University, 50 Nanynag Avenue, 639798, Singapore
7. Environmental Chemistry and Materials Centre, Nanyang Environment and Water Research Institute, 1 Cleantech Loop, 637141, Singapore