1. Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21287
2. Center for Bioengineering Innovation & Design, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21287
3. Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21287
4. Division of Gastroenterology, Department of Medicine, Johns Hopkins Medicine, Baltimore, MD 21287; Center for Bioengineering Innovation & Design, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21287