1. Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, Harvard T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts 02115, United States
2. School of Chemical and Biomedical Engineering, Nanyang Technological University, 637457 Singapore
3. Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06504, United States
4. School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore
5. Environmental Chemistry and Materials Centre, Nanyang Environment and Water Research Institute, 637141 Singapore
6. Environmental Microbiology and Food Safety Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, 10300 Baltimore Avenue, Beltsville, Maryland 20705, United States