Some properties of the organic matrix of a bovine cortical bone sample in various media

Abstract

Dimensional stability of a demineralized bovine cortical bone sample was found in all media whether EDTA, saline or ethanol and water solutions or even 100% ethanol. A 6% volume shrinkage was observed, in strong contrast to the reported swelling for tail tendon fiber collagen. Sonic velocity was strongly dependent on the state and the medium, varying by a factor greater than 2. The medium appears to contribute strongly to the observed velocity suggesting that the Reuss formalism is applicable with the solid collagen skeleton as one component and the liquid in the pores as the second. Sonic anisotropy was noted although the intensity varied. The radial to axial velocity was greatest (0.93) in saline and least in 100% ethanol (0.80) indicating that the rigidity of the tissue influenced the character of sonic propagation. Two sets of intermolecular linkages are inferred. One set, in common with tendon collagen, controls the elastic properties. A second set in bone collagen maintains dimensional stability.

Density of a sample bovine cortical bone matrix and its solid constituent in various media

“…From the eight sets of values the axial mean was 0.991 _+ 0.002; tangential, 0.978 + 0.002; radial, 0.970 + 0.004. The standard deviation refers to the observed variability of the plotted data with respect to the wet state thickness ratio for each orientation and is consistent with the limitations of the measurement process [9,10]. The mean volume ratio for all wet states was calculated from the three wet state thickness ratios using the above formula and found to be 0.939 +--0.007, where now the uncertainty is the sum of the three component standard deviations before roundoff.…”

“…where AVR is the estimated volume shrinkage, Details and numerical values for the wet states were given in a previous paper [ 10]. Figure 2 shows the thickness and volume ratios for all states including the dried bone matrix.…”

“…The density of a selected number of the demineralized desiccated specimens was found after 12 months in the desiccator. Details of the measurement techniques are given in the preceding papers [9,10]. All measurements were performed at room temperature (23~176…”

“…The axial sonic velocity of the matrix in 0.15 M saline was 1.82 km/s (10 MHz) [10], and the density of the wet matrix was calculated to be 1.186 + 0.009 g/cc. Harley et al [6] determined the axial velocity of collagen in rat tail tendon fiber in 0.15 M saline to be 2.62 km/s.…”

“…The data reported here were obtained during the investigation of other properties of the same bovine cortical bone sample [9,10].…”