TY - JOUR
T1 - In situ friction measurement on murine cartilage by atomic force microscopy
AU - Coles, Jeffrey M.
AU - Blum, Jason J.
AU - Jay, Gregory D.
AU - Darling, Eric M.
AU - Guilak, Farshid
AU - Zauscher, Stefan
N1 - Funding Information:
This work has been supported in part by NIH grants GM08555, EB01630, AR15768, AR50245 and AR50180. We thank Stephen Johnson and Andrea Clark for their assistance and for providing the mice used in this study.
PY - 2008
Y1 - 2008
N2 - Articular cartilage provides a low-friction, wear-resistant surface for the motion of diarthrodial joints. The objective of this study was to develop a method for in situ friction measurement of murine cartilage using a colloidal probe attached to the cantilever of an atomic force microscope. Sliding friction was measured between a chemically functionalized microsphere and the cartilage of the murine femoral head. Friction was measured at normal loads ranging incrementally from 20 to 100 nN with a sliding speed of 40 μm/s and sliding distance of 64 μm. Under these test conditions, hydrostatic pressurization and biphasic load support in the cartilage were minimized, providing frictional measurements that predominantly reflect boundary lubrication properties. Friction coefficients measured on murine tissue (0.25±0.11) were similar to those measured on porcine tissue (0.23±0.09) and were in general agreement with measurements of boundary friction on cartilage by other researchers. Using the colloidal probe as an indenter, the elastic mechanical properties and surface roughness were measured in the same configuration. Interfacial shear was found to be the principal mechanism of friction generation, with little to no friction resulting from plowing forces, collision forces, or energy losses due to normal deformation. This measurement technique can be applied to future studies of cartilage friction and mechanical properties on genetically altered mice or other small animals.
AB - Articular cartilage provides a low-friction, wear-resistant surface for the motion of diarthrodial joints. The objective of this study was to develop a method for in situ friction measurement of murine cartilage using a colloidal probe attached to the cantilever of an atomic force microscope. Sliding friction was measured between a chemically functionalized microsphere and the cartilage of the murine femoral head. Friction was measured at normal loads ranging incrementally from 20 to 100 nN with a sliding speed of 40 μm/s and sliding distance of 64 μm. Under these test conditions, hydrostatic pressurization and biphasic load support in the cartilage were minimized, providing frictional measurements that predominantly reflect boundary lubrication properties. Friction coefficients measured on murine tissue (0.25±0.11) were similar to those measured on porcine tissue (0.23±0.09) and were in general agreement with measurements of boundary friction on cartilage by other researchers. Using the colloidal probe as an indenter, the elastic mechanical properties and surface roughness were measured in the same configuration. Interfacial shear was found to be the principal mechanism of friction generation, with little to no friction resulting from plowing forces, collision forces, or energy losses due to normal deformation. This measurement technique can be applied to future studies of cartilage friction and mechanical properties on genetically altered mice or other small animals.
KW - Boundary lubrication
KW - Lubricin
KW - Scanning probe microscopy
KW - Tribology
UR - http://www.scopus.com/inward/record.url?scp=38749108068&partnerID=8YFLogxK
U2 - 10.1016/j.jbiomech.2007.10.013
DO - 10.1016/j.jbiomech.2007.10.013
M3 - Article
C2 - 18054362
AN - SCOPUS:38749108068
SN - 0021-9290
VL - 41
SP - 541
EP - 548
JO - Journal of Biomechanics
JF - Journal of Biomechanics
IS - 3
ER -