TY - JOUR
T1 - Computational and experimental methodology for site-matched investigations of the influence of mineral mass fraction and collagen orientation on the axial indentation modulus of lamellar bone
AU - Spiesz, Ewa M.
AU - Reisinger, Andreas G.
AU - Kaminsky, Werner
AU - Roschger, Paul
AU - Pahr, Dieter H.
AU - Zysset, Philippe K.
N1 - Funding Information:
The authors thank the Austrian Science Fund (FWF) for grant support (Grant no. P19009-N20 ), the Hochschuljubiläumsstiftung of Vienna for sponsoring a part of the used computational resources (Grant no. H-1906/2010 ), the AUVA (Austrian Social Insurance for Occupational Risk) and the WGKK (Social Health Insurance Vienna). Additionally, the authors would like to thank Thomas Tangl for providing assistance with the sample preparation and Phaedra Messmer for assistance with the qBEI measurements.
PY - 2013/12
Y1 - 2013/12
N2 - Relationships between mineralization, collagen orientation and indentation modulus were investigated in bone structural units from the mid-shaft of human femora using a site-matched design.Mineral mass fraction, collagen fibril angle and indentation moduli were measured in registered anatomical sites using backscattered electron imaging, polarized light microscopy and nano-indentation, respectively. Theoretical indentation moduli were calculated with a homogenization model from the quantified mineral densities and mean collagen fibril orientations.The average indentation moduli predicted based on local mineralization and collagen fibers arrangement were not significantly different from the average measured experimentally with nanoindentation (. p=0.9). Surprisingly, no substantial correlation of the measured indentation moduli with tissue mineralization and/or collagen fiber arrangement was found.Nano-porosity, micro-damage, collagen cross-links, non-collagenous proteins or other parameters affect the indentation measurements. Additional testing/simulation methods need to be considered to properly understand the variability of indentation moduli, beyond the mineralization and collagen arrangement in bone structural units.
AB - Relationships between mineralization, collagen orientation and indentation modulus were investigated in bone structural units from the mid-shaft of human femora using a site-matched design.Mineral mass fraction, collagen fibril angle and indentation moduli were measured in registered anatomical sites using backscattered electron imaging, polarized light microscopy and nano-indentation, respectively. Theoretical indentation moduli were calculated with a homogenization model from the quantified mineral densities and mean collagen fibril orientations.The average indentation moduli predicted based on local mineralization and collagen fibers arrangement were not significantly different from the average measured experimentally with nanoindentation (. p=0.9). Surprisingly, no substantial correlation of the measured indentation moduli with tissue mineralization and/or collagen fiber arrangement was found.Nano-porosity, micro-damage, collagen cross-links, non-collagenous proteins or other parameters affect the indentation measurements. Additional testing/simulation methods need to be considered to properly understand the variability of indentation moduli, beyond the mineralization and collagen arrangement in bone structural units.
KW - Collagen fibril orientation
KW - Homogenization
KW - Mineralization
KW - Nanoindentation
KW - Quantitative polarized light microscopy (qPLM)
KW - Site-matching
UR - http://www.scopus.com/inward/record.url?scp=84883257097&partnerID=8YFLogxK
U2 - 10.1016/j.jmbbm.2013.07.004
DO - 10.1016/j.jmbbm.2013.07.004
M3 - Journal article
C2 - 23994944
AN - SCOPUS:84883257097
SN - 1751-6161
VL - 28
SP - 195
EP - 205
JO - Journal of the mechanical behavior of biomedical materials
JF - Journal of the mechanical behavior of biomedical materials
ER -