Design and Validation of a Cyclic Strain Bioreactor to Condition Spatially-Selective Scaffolds in Dual Strain Regimes
by
J. Matthew Goodhart, Jared O. Cooper, Richard A. Smith, John L. Williams, Warren O. Haggard and Joel D. Bumgardner *
J. Matthew Goodhart, Jared O. Cooper, Richard A. Smith, John L. Williams, Warren O. Haggard and Joel D. Bumgardner *
Joint Biomedical Engineering Graduate Program, University of Memphis-University of Tennessee Health Science Center, University of Memphis, ET 330, Memphis, TN 38152, USA
*
Author to whom correspondence should be addressed.
Processes 2014, 2(2), 345-360; https://doi.org/10.3390/pr2020345
Received: 22 November 2013 / Revised: 31 January 2014 / Accepted: 21 February 2014 / Published: 31 March 2014
(This article belongs to the Special Issue Design of Bioreactor Systems for Tissue Engineering)
The objective of this study was to design and validate a unique bioreactor design for applying spatially selective, linear, cyclic strain to degradable and non-degradable polymeric fabric scaffolds. This system uses a novel three-clamp design to apply cyclic strain via a computer controlled linear actuator to a specified zone of a scaffold while isolating the remainder of the scaffold from strain. Image analysis of polyethylene terephthalate (PET) woven scaffolds subjected to a 3% mechanical stretch demonstrated that the stretched portion of the scaffold experienced 2.97% ± 0.13% strain (mean ± standard deviation) while the unstretched portion experienced 0.02% ± 0.18% strain. NIH-3T3 fibroblast cells were cultured on the PET scaffolds and half of each scaffold was stretched 5% at 0.5 Hz for one hour per day for 14 days in the bioreactor. Cells were checked for viability and proliferation at the end of the 14 day period and levels of glycosaminoglycan (GAG) and collagen (hydroxyproline) were measured as indicators of extracellular matrix production. Scaffolds in the bioreactor showed a seven-fold increase in cell number over scaffolds cultured statically in tissue culture plastic petri dishes (control). Bioreactor scaffolds showed a lower concentration of GAG deposition per cell as compared to the control scaffolds largely due to the great increase in cell number. A 75% increase in hydroxyproline concentration per cell was seen in the bioreactor stretched scaffolds as compared to the control scaffolds. Surprisingly, little differences were experienced between the stretched and unstretched portions of the scaffolds for this study. This was largely attributed to the conditioned and shared media effect. Results indicate that the bioreactor system is capable of applying spatially-selective, linear, cyclic strain to cells growing on polymeric fabric scaffolds and evaluating the cellular and matrix responses to the applied strains.
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Keywords:
bioreactor; cyclic strain; fibroblast; tendon; cell-culture
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MDPI and ACS Style
Goodhart, J.M.; Cooper, J.O.; Smith, R.A.; Williams, J.L.; Haggard, W.O.; Bumgardner, J.D. Design and Validation of a Cyclic Strain Bioreactor to Condition Spatially-Selective Scaffolds in Dual Strain Regimes. Processes 2014, 2, 345-360.
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