title: Elliptical posts allow for detailed control of non-equibiaxial straining of cell cultures.
abstract: BACKGROUND
  A modification of the Flexcell system that allows imposition of homogenous, controlled non-equibiaxial strains to cell cultures is developed and experimentally validated. The Flexcell system by default applies equibiaxial strain to cell cultures, meaning no shear strain, while soft tissue cells in vivo are subjected to a range of mechanical deformations including shear strain caused by activities of daily living. Shear strains are suspected to play an important role in tissue necrosis.
  
  
  METHODS
  The Flexcell system was redesigned using a finite element model in order to obtain large areas of the membrane in a controlled, uniform non-equibiaxial strain state.
  
  
  RESULTS
  The redesign was manufactured and the resulting strains were experimentally validated by means of image analysis methods. The results showed that the system could be used for experiments varying the shear strain.
  
  
  CONCLUSIONS
  The result allows scientists and experimentalists to apply detailed control of the strain tensor applied to tissue samples in two dimensions.
authors.affiliation: Department of Mechanical and Manufacturing Engineering, Aalborg University, Aalborg, Denmark. cgo@m-tech.aau.dk
authors.forename: Christian Gammelgaard
authors.initials: CG
authors.lastname: Olesen
authors.forename: Christian Pablo
authors.initials: CP
authors.lastname: Pennisi
authors.forename: Mark
authors.initials: M
authors.lastname: de Zee
authors.forename: Vladimir
authors.initials: V
authors.lastname: Zachar
authors.forename: John
authors.initials: J
authors.lastname: Rasmussen
mesh_terms: D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods*; D005347:Fibroblasts / Q000166:cytology* / Q000502:physiology; D020342:Finite Element Analysis; D006801:Humans; D003668:Pressure Ulcer / Q000473:pathology* / Q000503:physiopathology; D013314:Stress, Mechanical