University of Health Sciences and Pharmacy 1 article published in JoVE Medicine Biological Preparation and Mechanical Technique for Determining Viscoelastic Properties of Zonular Fibers Juan Rodriguez1,2, Matthew Reilly3, Robert P. Mecham4, Steven Bassnett2,4 1Department of Basic Sciences, University of Health Sciences and Pharmacy, 2Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, 3Department of Biomedical Engineering, The Ohio State University, 4Department of Cell Biology & Physiology, Washington University School of Medicine The protocol describes a method for the study of extracellular matrix viscoelasticity and its dependence on protein composition or environmental factors. The matrix system targeted is the mouse zonule. The performance of the method is demonstrated by comparing the viscoelastic behavior of wild-type zonular fibers with those lacking microfibril-associated glycoprotein-1.