1. Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
2. Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
3. Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
4. Fiber and Polymer Science Program, Textile Engineering, Chemistry, and Science Department, North Carolina State University, Raleigh, North Carolina 27695, United States
5. Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States