Permeability of Cortical Bone to Large Molecular Weight Proteins Under Diffusive and Load-Induced Convective Transport Mechanisms

Abstract

The composition of bone is 75% mineral and organic components and 25% fluid; yet until the past 30 years, the fluid component of bone had been ignored [1]. The idea of load induced fluid flow via pressure gradients was hypothesized for the first time by Piekarski et al in his application of Biot’s poroelasticity theory [2]. Poroelasticity theory mathematically describes the sponge-like behavior of bone: when bone is squeezed(loaded) fluid will be induced to flow. However although the concept of load induced fluid flow is well accepted in the orhopedic field, our study is the first to provide quantitative evidence of the effect of load induced fluid on macromolecular transport. Hence the goals of this study include observing permeability of large molecular weight tracers in cortical bone, ii.) comparing molecular size dependence on tracer permeability in cortical bone, and iii.) comparing effects of convective and diffusive transport mechanisms on permeability.