Novel Wound Tear Model for 3D Bioartificial Constructs In Vitro

Wimmer C, Addison K, Frazier C, Qi J, Banes AJ. 14th Annual Conference of the North Carolina Tissue Engineering and Regenerative Medicine Society, Raleigh, NC, September 10, 2012.

Wound models for connective tissues in vitro generally test for kinetics of cell migration, toxicity or apoptosis in response to a drug. We have developed a 3D wound and tear model for bioartificial tendon to test the effects of compounds that are stimulatory for tenocytes in response to traumatic injury as well as mechanical stimulation. A 6 place, trough loader was created in Solidworks with dual arm, y-shaped cavities and submitted for construction of a rapid prototyped polymeric device to fit beneath a standard BioFlex, rubber bottomed culture plate. A nonwoven nylon mesh was bonded to the membrane at the outside segments of arms and at the base of the Y with tabular extensions to capture a cell-populated hydrogel. The bottoms of the cavities have holes through which vacuum can draw down the rubber membrane to create a void for deposition of a cell-seeded collagen gel (bioartificial tendons, BATs). Once gels have compacted for three days, a modified arctangular loading post was placed beneath the membrane to apply tension across the Y arm. Strains of up to 18% can be applied to create a tear at the stress riser at the crotch of the Y with a vacuum-based system. Cells can be mechanically conditioned at low strain and low frequency or subjected to traumatic injury by high strain cycling of the construct. Live/dead cell counts DNA be made in situ or by releasing cells from the matrix and performing direct cells counts.