title: Surface ultrastructure and mechanical property of human chondrocyte revealed by atomic force microscopy.
abstract: OBJECTIVE
  The mechanical properties of chondrocytes influence maintenance of the articular cartilage extracellular matrix. To differentiate the mechanical properties of chondrocytes between a young, normal modulus and an old, osteoarthritic (OA) modulus, we used an atomic force microscope (AFM) to probe the surface ultrastructure and to measure their adhesion force and stiffness.
  
  
  METHODS
  We directly visualized a single chondrocyte cell by using AFM and quantitatively measured the dimensions of the cells.
  
  
  RESULTS
  Profiles displayed heights of 1026+/-203 and 1668+/-352 nm for old and young cells, respectively. Contour maps revealed differences in the sizes and structures of the two groups. Mean calculated adhesion forces differed between normal and OA chondrocytes (7.06+/-3.35 and 2.97+/-1.82 nN, respectively), as did calculated stiffness values (0.0960+/-0.009 and 0.0347+/-0.005 N/m, respectively).
  
  
  CONCLUSIONS
  These findings suggested that the mechanical properties of normal chondrocytes substantially differed from those of OA chondrocytes. We believe this study represents the first direct characterization of the surface ultrastructure and mechanical measurements of human chondrocytes between normal and OA stages. This new approach could be a useful technique for investigating age-related changes in the properties of human chondrocytes.
authors.affiliation: Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: C-H
authors.initials: CH
authors.lastname: Hsieh
authors.forename: Y-H
authors.initials: YH
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Lin
authors.forename: J-J
authors.initials: JJ
authors.lastname: Tsai-Wu
authors.forename: C H
authors.initials: CH
authors.lastname: Herbert Wu
authors.forename: C-C
authors.initials: CC
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002358:Cartilage, Articular / Q000166:cytology* / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000502:physiology; D048429:Cell Size; D019902:Chondrocytes / Q000502:physiology / Q000648:ultrastructure*; D005109:Extracellular Matrix; D005434:Flow Cytometry; D006801:Humans; D018625:Microscopy, Atomic Force / Q000379:methods*; D008875:Middle Aged; D010003:Osteoarthritis / Q000473:pathology; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D015815:Cell Adhesion Molecules