Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland. School of Medicine, Pharmacy, and Health, Durham University, Stockton-on-Tees, United Kingdom; and. Institute of Health and Society, Newcastle University, Newcastle upon Tyne, United Kingdom. Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland. Laboratory of Organic Chemistry, ETH Zurich, Zurich, Switzerland. Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; steingoetter@biomed.ee.ethz.ch.