1. Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics Eshelman School of Pharmacy University of North Carolina at Chapel Hill Chapel Hill NC 27599 USA
2. Department of Chemical and Biomolecular Engineering University of Delaware 150 Academy Street Newark DE 19716 USA
3. NIST Center for Neutron Research National Institute of Standards and Technology 100 Bureau Drive Gaithersburg MD 20899 USA
4. Research Computer Center University of North Carolina Chapel Hill Chapel Hill NC 27599 USA
5. Department of Biochemistry and Biophysics School of Medicine University of North Carolina at Chapel Hill Chapel Hill NC 27599 USA
6. Eshelman School of Pharmacy University of North Carolina at Chapel Hill Chapel Hill NC 27599 USA
7. Laboratory of Chemical Design of Bionanomaterials Faculty of Chemistry M.V. Lomonosov Moscow State University Moscow 119992 Russia