Organic noncollagenous soluble (soluble to 4M Guanidine HCl) constituents make up a small part of the bone tissue, but they have important physiological functions in the ultrastructural arrangement and the mineralization phase of the bone matrix. In this project we shall investigate the contribution of the soluble noncollagenous organic part of the bone constituents to the electromechanical and viscoelastic properties of bone tissue. Preliminary particle electrophoresis measurements in our laboratory has shown that these constituents affect the streaming potentials due to change in zeta potentials because of their high electrical charge carrying capacities (Proteoglycans, sialoproteins, etc.). The streaming potentials have been suggested as the most important source of the biological signal due to the electromechanical properties of bone tissue. They play a significant role in the biofeedback mechanism of the bone tissue. The regeneration and remodeling capacities of bone tissue changes in time, from infant to adult, as does the amount of these noncollagenous constituents. In this research we shall be investigating the contribution of these noncollagenous organic constituents to the streaming potentials, and how their contribution changes with age. The viscoelastic behavior of the bone tissue depends upon different physical causes. The effects of viscous cement lines, which are rich in noncollagenous organic constituent, on the long-term deformation of the bone tissue has been shown. The following points will investigated; a) Particle electrophoresis measurements to determine the contribution of noncollagenous organic constitutents to the immobilized ionic volume charge density of the bone tissue. b) Using plug-shaped (right circular cylinders) intact bone specimens with different treatments (control versus 4M Guanidine HCl treated) we shall be able to measure streaming potentials in the bone in different orientations. This way we shall be able to see how the anisotropic bone structure affects the streaming potentials. c) The control versus chemically treated samples (4M Guanidine HCl) will be used in tension and bending experiments with different strain rates and in creep experiments, to find out the contribution of these constituents to the viscoelastic behavior of bone tissue. d) Specimens obtained from animals of different ages will reveal how the above points change with age parallel to the changes in these constituents.
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