title: The effect of surface modification on gliding ability of decellularized flexor tendon in a canine model in vitro.
abstract: OBJECTIVE
  To investigate the gliding ability and mechanical properties of decellularized intrasynovial tendons with and without surface modification designed to reduce gliding resistance.
  
  
  METHODS
  We randomly assigned 33 canine flexor digitorum profundus tendons to 1 of 3 groups: untreated fresh tendons, to serve as a control; tendons decellularized with trypsin and Triton X-100; and tendons decellularized as in group 2 with surface modification using carbodiimide-derivatized hyaluronic acid and gelatin (cd-HA-gelatin). Tendons were subjected to cyclic friction testing for 1,000 cycles with subsequent tensile stiffness testing. We qualitatively evaluated the surface roughness after 1,000 cycles using scanning electron microscopy.
  
  
  RESULTS
  The gliding resistance of the decellularized group was significantly higher than that of both the control and cd-HA-gelatin tendons (0.20, 0.09, and 0.11 N after the first cycle; and 0.41, 0.09, and 0.14 N after 1,000 cycles, respectively). Gliding resistance between the control and cd-HA-gelatin groups was not significantly different. The Young modulus was not significantly different between groups. The surfaces of the control and cd-HA-gelatin-treated tendons appeared smooth after 1,000 cycles, whereas those of the decellularized tendons appeared roughened under scanning electron microscopy observation.
  
  
  CONCLUSIONS
  Decellularization with trypsin and Triton X-100 did not change tendon stiffness. However, although this treatment was effective in removing cells, it adversely altered the tendon surface in both appearance and gliding resistance. Surface modification with cd-HA-gelatin improved the tendon surface smoothness and significantly decreased the gliding resistance.
  
  
  CONCLUSIONS
  The combination of decellularization and surface modification may improve the function of tendon allografts when used clinically.
authors.affiliation: Biomechanics and Tendon and Soft Tissue Laboratories, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ozasa
authors.forename: Peter C
authors.initials: PC
authors.lastname: Amadio
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Thoreson
authors.forename: Kai-Nan
authors.initials: KN
authors.lastname: An
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Zhao
mesh_terms: D064591:Allografts; D000818:Animals; D001696:Biomechanical Phenomena; D004285:Dogs; D017276:Friction / Q000187:drug effects*; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D017830:Octoxynol / Q000494:pharmacology*; D013499:Surface Properties / Q000187:drug effects; D013501:Surface-Active Agents / Q000627:therapeutic use*; D013710:Tendons / Q000503:physiopathology*; D014357:Trypsin / Q000494:pharmacology*
chemical_list: D013501:Surface-Active Agents; D017830:Octoxynol; D014357:Trypsin
keywords: Allograft; decellularization; flexor tendon; gliding resistance