The measurement of biomechanical properties of porcine articular cartilage using atomic force microscopy

Articular cartilage is the connective tissue that lines the articulating surfaces of diarthrodial joints, providing a low-friction, load-bearing surface during joint motion. Articular cartilage comprises of a single cell type, the chondrocyte, embedded within an extensive extracellular matrix (ECM). Each chondrocyte is surrounded by a narrow region called the pericellular matrix (PCM) that is distinct from the ECM in both its biochemical composition [1] and biomechanical properties [2]. While multiple techniques have been used to measure the mechanical properties of the PCM, including micropipette aspiration of isolated chondrons [2], these studies required mechanical or enzymatic extraction of the chondrocyte and surrounding PCM (i.e., the “chondron” [1]) from the cartilage, and the influence of this isolation process on PCM properties is unknown. Atomic force microscopy (AFM) provides a high resolution form of nano- and microindentation approaches that can be used to measure local mechanical properties in situ [3,4]. The objective of this study was to use AFM to quantify the biomechanical properties of the ECM and PCM of human articular cartilage in situ.

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Investigation of articular cartilage structural and biomechanical properties by atomic-force microscopy

Osteoarthritis and Cartilage ◽

10.1016/j.joca.2018.02.776 ◽

2018 ◽

Vol 26 ◽

pp. S400 ◽

Cited By ~ 1

Author(s):

C. Prein ◽

F. Lagugne-Labarthet ◽

F. Beier

Keyword(s):

Atomic Force Microscopy ◽

Articular Cartilage ◽

Biomechanical Properties ◽

Force Microscopy ◽

Atomic Force

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Spatial Mapping of the Biomechanical Properties of the Pericellular Matrix of Articular Cartilage Measured In Situ via Atomic Force Microscopy

Biophysical Journal ◽

10.1016/j.bpj.2010.03.037 ◽

2010 ◽

Vol 98 (12) ◽

pp. 2848-2856 ◽

Cited By ~ 92

Author(s):

Eric M. Darling ◽

Rebecca E. Wilusz ◽

Michael P. Bolognesi ◽

Stefan Zauscher ◽

Farshid Guilak

Keyword(s):

Atomic Force Microscopy ◽

Articular Cartilage ◽

Biomechanical Properties ◽

Spatial Mapping ◽

Pericellular Matrix ◽

Force Microscopy ◽

Atomic Force

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Immunofluorescence-guided atomic force microscopy to measure the micromechanical properties of the pericellular matrix of porcine articular cartilage

Journal of The Royal Society Interface ◽

10.1098/rsif.2012.0314 ◽

2012 ◽

Vol 9 (76) ◽

pp. 2997-3007 ◽

Cited By ~ 37

Author(s):

Rebecca E. Wilusz ◽

Louis E. DeFrate ◽

Farshid Guilak

Keyword(s):

Atomic Force Microscopy ◽

Articular Cartilage ◽

Elastic Moduli ◽

Articular Surface ◽

Biomechanical Properties ◽

Pericellular Matrix ◽

Type Vi Collagen ◽

Force Microscopy ◽

Micromechanical Properties ◽

Atomic Force

The pericellular matrix (PCM) is a narrow region that is rich in type VI collagen that surrounds each chondrocyte within the extracellular matrix (ECM) of articular cartilage. Previous studies have demonstrated that the chondrocyte micromechanical environment depends on the relative properties of the chondrocyte, its PCM and the ECM. The objective of this study was to measure the influence of type VI collagen on site-specific micromechanical properties of cartilage in situ by combining atomic force microscopy stiffness mapping with immunofluorescence imaging of PCM and ECM regions in cryo-sectioned tissue samples. This method was used to test the hypotheses that PCM biomechanical properties correlate with the presence of type VI collagen and are uniform with depth from the articular surface. Control experiments verified that immunolabelling did not affect the properties of the ECM or PCM. PCM biomechanical properties correlated with the presence of type VI collagen, and matrix regions lacking type VI collagen immediately adjacent to the PCM exhibited higher elastic moduli than regions positive for type VI collagen. PCM elastic moduli were similar in all three zones. Our findings provide further support for type VI collagen in defining the chondrocyte PCM and contributing to its biological and biomechanical properties.

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