title: See-saw rocking: an in vitro model for mechanotransduction research.
abstract: In vitro mechanotransduction studies, uncovering the basic science of the response of cells to mechanical forces, are essential for progress in tissue engineering and its clinical application. Many varying investigations have described a multitude of cell responses; however, as the precise nature and magnitude of the stresses applied are infrequently reported and rarely validated, the experiments are often not comparable, limiting research progress. This paper provides physical and biological validation of a widely available fluid stimulation device, a see-saw rocker, as an in vitro model for cyclic fluid shear stress mechanotransduction. This allows linkage between precisely characterized stimuli and cell monolayer response in a convenient six-well plate format. Models of one well were discretized and analysed extensively using computational fluid dynamics to generate convergent, stable and consistent predictions of the cyclic fluid velocity vectors at a rocking frequency of 0.5 Hz, accounting for the free surface. Validation was provided by comparison with flow velocities measured experimentally using particle image velocimetry. Qualitative flow behaviour was matched and quantitative analysis showed agreement at representative locations and time points. Maximum shear stress of 0.22 Pa was estimated near the well edge, and time-average shear stress ranged between 0.029 and 0.068 Pa. Human tenocytes stimulated using the system showed significant increases in collagen and GAG secretion at 2 and 7 day time points. This in vitro model for mechanotransduction provides a versatile, flexible and inexpensive method for the fluid shear stress impact on biological cells to be studied.
authors.affiliation: Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Botnar Research Centre, Oxford OX3 7LD, UK russell.tucker@eng.ox.ac.uk.
authors.forename: R P
authors.initials: RP
authors.lastname: Tucker
authors.affiliation: Department of Zoology, University of Oxford, Botnar Research Centre, Oxford OX3 7LD, UK Department of Biology, Lund University, Lund, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Henningsson
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Oxford OX3 7LD, UK.
authors.forename: S L
authors.initials: SL
authors.lastname: Franklin
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
authors.forename: D
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Botnar Research Centre, Oxford OX3 7LD, UK Department of Mechanical Engineering, University College London, London WC1E 6BT, UK.
authors.forename: Y
authors.initials: Y
authors.lastname: Ventikos
authors.affiliation: Department of Zoology, University of Oxford, Botnar Research Centre, Oxford OX3 7LD, UK Structure and Motion Laboratory, Royal Veterinary College, Hatfield AL9 7TA, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Bomphrey
authors.affiliation: Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Botnar Research Centre, Oxford OX3 7LD, UK.
authors.forename: M S
authors.initials: MS
authors.lastname: Thompson
mesh_terms: D002478:Cells, Cultured; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005434:Flow Cytometry / Q000295:instrumentation*; D006801:Humans; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D008846:Micromanipulation / Q000295:instrumentation; D008954:Models, Biological; D009991:Oscillometry / Q000295:instrumentation*; D010812:Physical Stimulation / Q000295:instrumentation*; D013314:Stress, Mechanical; D013710:Tendons / Q000166:cytology* / Q000502:physiology*
keywords: computational fluid dynamics; cyclic fluid flow; particle image velocimetry; rocking; shear stress; tenocytes