title: Biomechanical and magnetic resonance characteristics of a cartilage-like equivalent generated in a suspension culture.
abstract: OBJECTIVE
  To generate a cartilage biomaterial using a suspension culture with biophysical properties similar to native articular cartilage.
  
  
  METHODS
  A novel cartilage tissue equivalent (CTE) using a no-scaffold, high-density suspension culture of neonatal porcine chondrocytes was formed on poly 2-hydroxyethyl methacrylate-treated plates for up to 16 weeks. Equilibrium aggregate modulus and hydraulic permeability were measured at 8 and 16 weeks using confined compression stress relaxation experiments. The CTE proteoglycan composition was characterized using sodium and T(1rho) magnetic resonance imaging methods after 8 weeks.
  
  
  RESULTS
  The resultant CTE produces a biomaterial consistent with a hyaline cartilage phenotype in appearance and expression of type II collagen and aggrecan. The equilibrium aggregate modulus and permeability for the 8-week specimens were 41.6 (standard deviation (SD) 4.3) kPa and 2.85(-13) (SD 2.45(-13)) m(4)/Ns, respectively, and, for the 16-week specimens, 35.2 (SD 7.6) kPa and 2.67(-13) (SD 1.06(-13)) m(4)/Ns, respectively. Average sodium concentration of the 8-week CTE ranged from 260 to 278 mM and average T(1rho) relaxation times from 105 to 107 ms, indicating proteoglycan content similar to that of native articular cartilage.
  
  
  CONCLUSIONS
  The high-density culture method produced a CTE with characteristics that approach those of native articular cartilage. The CTE mechanical properties are similar to those of the native cartilage. The CTE developed in this study represents a promising methodological advancement in cartilage tissue engineering and cartilage repair.
authors.affiliation: Center for Biomedical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, Delaware, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Novotny
authors.forename: Christina M
authors.initials: CM
authors.lastname: Turka
authors.forename: Changhoon
authors.initials: C
authors.lastname: Jeong
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Wheaton
authors.forename: Chuanzhao
authors.initials: C
authors.lastname: Li
authors.forename: Ana
authors.initials: A
authors.lastname: Presedo
authors.forename: Dean W
authors.initials: DW
authors.lastname: Richardson
authors.forename: Ravinder
authors.initials: R
authors.lastname: Reddy
authors.forename: George R
authors.initials: GR
authors.lastname: Dodge
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001696:Biomechanical Phenomena / Q000379:methods; D002358:Cartilage, Articular / Q000166:cytology* / Q000502:physiology*; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000502:physiology*; D019245:Compressive Strength; D004548:Elasticity; D008279:Magnetic Resonance Imaging; D010539:Permeability; D013552:Swine; D013718:Tensile Strength; D023822:Tissue Engineering / Q000379:methods*