title: Characterization of a novel bioreactor system for 3D cellular mechanobiology studies.
abstract: In vitro engineering systems can be powerful tools for studying tissue development in response to biophysical stimuli as well as for evaluating the functionality of engineered tissue grafts. It has been challenging, however, to develop systems that adequately integrate the application of biomimetic mechanical strain to engineered tissue with the ability to assess functional outcomes in real time. The aim of this study was to design a bioreactor system capable of real-time conditioning (dynamic, uniaxial strain, and electrical stimulation) of centimeter-long 3D tissue engineered constructs simultaneously with the capacity to monitor local strains. The system addresses key limitations of uniform sample loading and real-time imaging capabilities. Our system features an electrospun fibrin scaffold, which exhibits physiologically relevant stiffness and uniaxial alignment that facilitates cell adhesion, alignment, and proliferation. We have demonstrated the capacity for directly incorporating human adipose-derived stromal/stem cells into the fibers during the electrospinning process and subsequent culture of the cell-seeded constructs in the bioreactor. The bioreactor facilitates accurate pre-straining of the 3D constructs as well as the application of dynamic and static uniaxial strains while monitoring bulk construct tensions. The incorporation of fluorescent nanoparticles throughout the scaffolds enables in situ monitoring of local strain fields using fluorescent digital image correlation techniques, since the bioreactor is imaging compatible, and allows the assessment of local sample stiffness and stresses when coupled with force sensor measurements. In addition, the system is capable of measuring the electromechanical coupling of skeletal muscle explants by applying an electrical stimulus and simultaneously measuring the force of contraction. The packaging of these technologies, biomaterials, and analytical methods into a single bioreactor system has produced a powerful tool that will enable improved engineering of functional 3D ligaments, tendons, and skeletal muscles. Biotechnol. Bioeng. 2016;113: 1825-1837. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 400 N. Broadway, Smith 5023, Baltimore, Maryland, 21287.|Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Colin A
authors.initials: CA
authors.lastname: Cook
authors.affiliation: Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 400 N. Broadway, Smith 5023, Baltimore, Maryland, 21287.|Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland.|Department of Biomedical Engineering, Ankara University Faculty of Engineering, Ankara, Turkey.
authors.forename: Pinar Y
authors.initials: PY
authors.lastname: Huri
authors.affiliation: Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 400 N. Broadway, Smith 5023, Baltimore, Maryland, 21287.|Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Ginn
authors.affiliation: Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 400 N. Broadway, Smith 5023, Baltimore, Maryland, 21287.|Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Jordana
authors.initials: J
authors.lastname: Gilbert-Honick
authors.affiliation: Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 400 N. Broadway, Smith 5023, Baltimore, Maryland, 21287.|Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Somers
authors.affiliation: Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 400 N. Broadway, Smith 5023, Baltimore, Maryland, 21287.
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Temple
authors.affiliation: Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 400 N. Broadway, Smith 5023, Baltimore, Maryland, 21287.|Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland.|Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland.|Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Hai-Quan
authors.initials: HQ
authors.lastname: Mao
authors.affiliation: Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 400 N. Broadway, Smith 5023, Baltimore, Maryland, 21287. wgrayson@jhmi.edu.|Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland. wgrayson@jhmi.edu.|Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland. wgrayson@jhmi.edu.|Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland. wgrayson@jhmi.edu.
authors.forename: Warren L
authors.initials: WL
authors.lastname: Grayson
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D001672:Biocompatible Materials; D001703:Biophysics / Q000295:instrumentation* / Q000379:methods*; D019149:Bioreactors; D018929:Cell Culture Techniques / Q000295:instrumentation*; D002478:Cells, Cultured; D004867:Equipment Design; D006801:Humans; D013234:Stem Cells / Q000502:physiology; D023822:Tissue Engineering
chemical_list: D001672:Biocompatible Materials
keywords: biomaterials; biomimetic; bioreactor; mechanobiology