Investigating the Life Expectancy and Proteolytic Degradation of Engineered Skeletal Muscle Biological Machines

• Type of Material: Article
• Authors: Caroline Cvetkovic, University of Illinois; Meghan C. Ferrall-Fairbanks, Georgia Institute of Technology; Eunkyung Ko, University of Illinois; Lauren Grant, University of Illinois; Hyunjoon Kong, University of Illinois; Manu Platt, Emory University; Rashid Bashir, University of Illinois
• Language: English
• Date: 2017-06-19
• Publisher: NATURE PUBLISHING GROUP
• Publication Version: Final Published Version
• Copyright Statement: © 2017 The Author(s).
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/s41598-017-03723-8
• Title of Journal or Parent Work: SCIENTIFIC REPORTS
• Volume: 7
• Issue: 1
• Start Page: 3775
• End Page: 3775
• Grant/Funding Information: This project was funded by the National Science Foundation STC: Emergent Behavior of Integrated Cellular Systems (Grant CBET-0939511) and NSF Cellular and Molecular Mechanics and Bionanotechnology (CMMB) Integrative Graduate Education and Research Traineeship (IGERT) (Grant 0965918).
• Keywords: FIBRIN; FABRICATION; Science & Technology - Other Topics; BREAST; V ACTIVITY; ZYMOGRAPHY; STEREOLITHOGRAPHY; Science & Technology; IN-VITRO; CANCER; CATHEPSIN K; Multidisciplinary Sciences; CYSTEINE CATHEPSINS
• Research Categories: Health Sciences, Oncology

Abstract

A combination of techniques from 3D printing, tissue engineering and biomaterials has yielded a new class of engineered biological robots that could be reliably controlled via applied signals. These machines are powered by a muscle strip composed of differentiated skeletal myofibers in a matrix of natural proteins, including fibrin, that provide physical support and cues to the cells as an engineered basement membrane. However, maintaining consistent results becomes challenging when sustaining a living system in vitro. Skeletal muscle must be preserved in a differentiated state and the system is subject to degradation by proteolytic enzymes that can break down its mechanical integrity. Here we examine the life expectancy, breakdown, and device failure of engineered skeletal muscle bio-bots as a result of degradation by three classes of proteases: Plasmin, cathepsin L, and matrix metalloproteinases (MMP-2 and MMP-9). We also demonstrate the use of gelatin zymography to determine the effects of differentiation and inhibitor concentration on protease expression. With this knowledge, we are poised to design the next generation of complex biological machines with controllable function, specific life expectancy and greater consistency. These results could also prove useful for the study of disease-specific models, treatments of myopathies, and other tissue engineering applications.