1. Department of Chemical Engineering, McMaster University, 1280 Main St. West, Hamilton, Ontario L8S 4M1, Canada
2. Biointerfaces Institute, McMaster University, 1280 Main St. West, Hamilton, Ontario L8S 4M1, Canada
3. Nano-Imaging and Spectroscopy Laboratory, Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario L1G 0C5, Canada