1. Cancer Center and Department of Pathology, University of New Mexico School of Medicine, NSF Center for Micro-Engineered Materials, and Chemical and Nuclear Engineering and Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Bio-sciences Division and National Flow Cytometry Resource, Los Alamos National Laboratories, Los Alamos, New Mexico 87545, and Department of Chemical and Environmental Engineering, Illinois Institute of Technology, Chicago, Illinois 60616