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, NC 27599, USA.
2. Joint UNC/NC State Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599-7575, USA.
3. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
4. Department of Biology, Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
5. Division of Hematology and Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
6. Department of Medicine, 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.