NANOINDENTATION OF BONE - Nanoindentation with Biological Applications - page 223

The positive and non-linear relationship between E and mineral V f
exists over a range of mineralization levels ( Fig. 7-4 ) 127 and tissue
types ( Fig. 7-6 ) . 50,172 Similar approaches to correlate nanomechanical
properties to site-matched measurements of factors that include mineral
composition, crystallinity, or organization of the mineral or underlying
collagen will provide additional insight into the structure-property-
function relationships at the tissue-level.
4.4. Fossilization
It is well established that there is a positive correlation between increased
mineral volume fraction and the stiffness, or modulus, of mineralized
material. 49,132 However, a large range of modulus values for bone is
observed at a constant mineral content and thus mechanical properties
cannot be explained by the mineral volume fraction and composites
theory alone. 132 The variation in modulus may also be related to changes
Figure 7-7. Modulus values of fossilized cortical bone samples plotted for each
geological age (note: x-axis is not evenly scaled). Data were compared via two-
way analysis of variance (ANOVA). A Dunnett's post-hoc analysis shows all fossilized
bone moduli values are statistically different from modern bone for p < 0.05. Apatite
and quartz values are included for comparison to reference samples with relevant
composition. 176