Mineralized Collagen Fibrils: A Mechanical Model with a Staggered Arrangement of Mineral Particles

Abstract

Both elastic modulus and fracture stress are known to increase with the amount of mineral deposited within collagen fibrils. Current mechanical models of mineralized fibrils, where mineral platelets are arranged in parallel arrays, reproduce the first effect but fail to predict an increase in fracture stress. Here, we propose a model with a staggered array of platelets that is in better agreement with results on molecular packing in collagen fibrils and that accounts for an increase of both elastic modulus and fracture stress with the amount of mineral in the fibril. Finally, we explore the dependence of the mechanical properties within the model, when the degree of mineralization and the thickness of the platelets as well as their distance varies.

A three-scale finite element investigation into the effects of tissue mineralisation and lamellar organisation in human cortical and trabecular bone

“…In the case of the 17nm inter-crystal spacing, the model fulfils the axial periodicity of collagen structures which is thought to be close to 67nm (Jäger and Fratzl 2000) (note that for all other parameter studies, an inter-crystal spacing of 5nm was assumed based the similar behaviour of the mineral-collagen structure at each inter-crystal spacing examined, see results section).…”

Bone Material Properties in Osteogenesis Imperfecta

“…(50) The platelets appear to grow and mature over time; hence, older bone has a higher mineralization density. The platelets extend beyond the individual fibrils into the gap channels; estimates of the distribution of mineral between the intra-and extrafibrillar regions vary, but typically are around one-third inside, two-thirds outside.…”

Measurement of the Mechanical Properties of Bone: A Recent History

“…There has been progress over the years [17,24,25,43,59]. Recently these efforts have taken on new importance because it is becoming possible to measure the mechanical properties of very small pieces of bone, so the relationship between theory and reality is gradually becoming clearer, though it has not yet arrived [21][22][23].…”