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Journal of the Royal Society, Interface Feb 2022Bone has a sophisticated architecture characterized by a hierarchical organization, starting at the sub-micrometre level. Thus, the analysis of the mechanical and...
Bone has a sophisticated architecture characterized by a hierarchical organization, starting at the sub-micrometre level. Thus, the analysis of the mechanical and structural properties of bone at this scale is essential to understand the relationship between its physiology, physical properties and chemical composition. Here, we unveil the potential of Brillouin-Raman microspectroscopy (BRaMS), an emerging correlative optical approach that can simultaneously assess bone mechanics and chemistry with micrometric resolution. Correlative hyperspectral imaging, performed on a human diaphyseal ring, reveals a complex microarchitecture that is reflected in extremely rich and informative spectra. An innovative method for mechanical properties analysis is proposed, mapping the intermixing of soft and hard tissue areas and revealing the coexistence of regions involved in remodelling processes, nutrient transportation and structural support. The mineralized regions appear elastically inhomogeneous, resembling the pattern of the osteons' lamellae, while Raman and energy-dispersive X-ray images through scanning electron microscopy show an overall uniform distribution of the mineral content, suggesting that other structural factors are responsible for lamellar micromechanical heterogeneity. These results, besides giving an important insight into cortical bone tissue properties, highlight the potential of BRaMS to access the origin of anisotropic mechanical properties, which are almost ubiquitous in other biological tissues.
Topics: Anisotropy; Bone and Bones; Cortical Bone; Haversian System; Humans; Microscopy, Electron, Scanning; Spectrum Analysis, Raman
PubMed: 35104431
DOI: 10.1098/rsif.2021.0642 -
Journal of Biomechanics Oct 2003Precise descriptions of the three-dimensional arrangements of collagen in bone are essential to understand the mechanical properties of this complex tissue. Transmission... (Review)
Review
Precise descriptions of the three-dimensional arrangements of collagen in bone are essential to understand the mechanical properties of this complex tissue. Transmission electron microscopy (TEM) analysis of decalcified human compact bone in section reveals characteristic patterns forming regular series of nested arcs. Such patterns are a direct consequence of an organization described as a twisted plywood and relate the distribution of collagen fibrils in osteons with that of molecules in cholesteric liquid crystals. The hypothesis that liquid crystalline properties are involved in the morphogenesis of dense collagen matrices was supported by data obtained in vitro. At a molecular level, acid-soluble collagen molecules spontaneously assemble, at concentrations of 50mg/ml or more, in precholesteric-banded patterns and cholesteric phases, identified by polarized light microscopy. In a more physiological context, these results were conforted, with the precursor molecule of collagen, procollagen, soluble at neutral pH. This protein spontaneously forms liquid crystalline precholesteric phases corresponding to banded patterns and birefringent cords. Stabilization of the liquid crystalline collagen, induced by pH modification and fibril formation, shows characteristic morphologies in TEM, which directly mimic arrays described in vivo. Undulating fibrils are indeed similar to crimp morphologies described in tendons and continuously twisting fibrils, and give rise to arced patterns similar to supra-molecular architectures identified in compact bone.
Topics: Biomechanical Phenomena; Bone and Bones; Collagen; Crystallization; Haversian System; Microscopy
PubMed: 14499304
DOI: 10.1016/s0021-9290(03)00134-9 -
Biomechanics and Modeling in... Dec 2022Cortical bone is a complex hierarchical structure consisting of biological fiber composites with transversely isotropic constituents, whose microstructures deserve...
Cortical bone is a complex hierarchical structure consisting of biological fiber composites with transversely isotropic constituents, whose microstructures deserve extensive study to understand the mechanism of living organisms and explore development of biomimetic materials. Based on this, we establish a three-level hierarchical structure from microscale to macroscale and propose a multiscale micromechanics model of cortical bone, which considers Haversian canal, osteonal lamellae, cement line and interstitial lamellae. In order to study the microstructural effect on the elastic behavior of hierarchical structures, the Mori-Tanaka model and locally exact homogenization theory are introduced for the homogenization of heterogeneous materials of microstructure at each level. Within sub-microscale, Haversian canal and Osteonal lamella are treated as fiber and matrix, whose homogenization is surrounded with cement line matrix in microstructure (or what we called "osteon") for the second homogenization; finally, osteon and interstitial lamella establish the meso-structure for the third homogenization, predicting the effective moduli of cortical bone. The correctness of the model in this paper is verified against the data in literature with good agreement. Finally, the dynamic viscoelastic response of cortical bones is investigated from a multiscale perspective, where the measured data are substituted into the present models to study the hydration and aging effect on bones' stiffness and viscoelasticity. It is demonstrated that the hydration is much more influential in affecting the storage and loss moduli of cortical bone than the aging effect. We also present a few numerical investigations on microstructural material and geometric parameters on the overall mechanical properties of cortical bone.
Topics: Elasticity; Biomechanical Phenomena; Haversian System; Bone and Bones; Cortical Bone; Models, Biological
PubMed: 36057052
DOI: 10.1007/s10237-022-01615-z -
Calcified Tissue International Jul 1982Cortical bone, at the osteonal level, consists of three phases: mineral, organic, and pore or void phases. In osteonal segments excised from mature human cortical bone,...
Cortical bone, at the osteonal level, consists of three phases: mineral, organic, and pore or void phases. In osteonal segments excised from mature human cortical bone, organic volume percent is a constant. Determination of the mineral and organic phase densities present in these segments has led to defining a simple relationship between percent mineralization and void volume. Studies of a group of osteonal segments from 5 human tibias suggest that porosity of up to 22.7% may exist. This is much more than is suggested by histological examination, leading to the conclusion that the majority of the void phase is present as a dispersed porosity.
Topics: Bone and Bones; Haversian System; Humans; Male; Mathematics; Models, Biological
PubMed: 6814721
DOI: 10.1007/BF02411263 -
Anatomical Record. Part B, New Anatomist Sep 2003Cortical bone is perforated by an interconnected network of porous canals that facilitate the distribution of neurovascular structures throughout the cortex. This... (Review)
Review
Cortical bone is perforated by an interconnected network of porous canals that facilitate the distribution of neurovascular structures throughout the cortex. This network is an integral component of cortical microstructure and, therefore, undergoes continual change throughout life as the cortex is remodeled. To date, the investigation of cortical microstructure, including the canal network, has largely been limited to the two-dimensional (2D) realm due to methodological hurdles. Thanks to continuing improvements in scan resolution, micro-computed tomography (muCT) is the first nondestructive imaging technology capable of resolving cortical canals. Like its application to trabecular bone, muCT provides an efficient means of quantifying aspects of 3D architecture of the canal network. Our aim here is to introduce the use of muCT for this application by providing examples, discussing some of the parameters that can be acquired, and relating these to research applications. Although several parameters developed for the analysis of trabecular microstructure are suitable for the analysis of cortical porosity, the algorithm used to estimate connectivity is not. We adapt existing algorithms based on skeletonization for this task. We believe that 3D analysis of the dimensions and architecture of the canal network will provide novel information relevant to many aspects of bone biology. For example, parameters related to the size, spacing, and volume of the canals may be particularly useful for investigation of the mechanical properties of bone. Alternatively, parameters describing the 3D architecture of the canal network, such as connectivity between the canals, may provide a means of evaluating cumulative remodeling related change.
Topics: Haversian System; Humans; Imaging, Three-Dimensional; Tomography, X-Ray Computed
PubMed: 12964207
DOI: 10.1002/ar.b.10024 -
Biomechanics and Modeling in... Dec 2008Bone remodelling is the process that maintains bone structure and strength through adaptation of bone tissue mechanical properties to applied loads. Bone can be modelled...
Bone remodelling is the process that maintains bone structure and strength through adaptation of bone tissue mechanical properties to applied loads. Bone can be modelled as a porous deformable material whose pores are filled with cells, organic material and interstitial fluid. Fluid flow is believed to play a role in the mechanotransduction of signals for bone remodelling. In this work, an osteon, the elementary unit of cortical bone, is idealized as a hollow cylinder made of a deformable porous matrix saturated with an interstitial fluid. We use Biot's poroelasticity theory to model the mechanical behaviour of bone tissue taking into account transverse isotropic mechanical properties. A finite element poroelastic model is developed in the COMSOL Multiphysics software. Elasticity equations and Darcy's law are implemented in this software; they are coupled through the introduction of an interaction term to obtain poroelasticity equations. Using numerical simulations, the investigation of the effect of spatial gradients of permeability or Poisson's ratio is performed. Results are discussed for their implication on fluid flow in osteons: (i) a permeability gradient affects more the fluid pressure than the velocity profile; (ii) focusing on the fluid flow, the key element of loading is the strain rate; (iii) a Poisson's ratio gradient affects both fluid pressure and fluid velocity. The influence of textural and mechanical properties of bone on mechanotransduction signals for bone remodelling is also discussed.
Topics: Animals; Bone Remodeling; Bone and Bones; Compressive Strength; Computer Simulation; Elasticity; Extracellular Fluid; Finite Element Analysis; Haversian System; Porosity; Stress, Mechanical; Weight-Bearing
PubMed: 17990014
DOI: 10.1007/s10237-007-0111-0 -
PloS One 2024The histological, or microscopic, appearance of bone tissue has long been studied to identify species-specific traits. There are several known histological...
The histological, or microscopic, appearance of bone tissue has long been studied to identify species-specific traits. There are several known histological characteristics to discriminate animal bone from human, but currently no histological characteristic that has been consistently identified in human bone exclusive to other mammals. The drifting osteon is a rare morphotype found in human long bones and observationally is typically absent from common mammalian domesticates. We surveyed previously prepared undecalcified histological sections from 25 species (human n = 221; nonhuman primate n = 24; nonprimate n = 169) to see if 1) drifting osteons were indeed more common in humans and 2) this could be a discriminating factor to identify human bone histologically. We conclude that drifting osteons are indeed more prevalent in human and nonhuman primate bone relative to nonprimate mammalian bone. Two criteria identify a rib or long bone fragment as human, assuming the fragment is unlikely to be from a nonhuman primate given the archaeological context: 1) at least two drifting osteons are present in the cross-section and 2) a drifting osteon prevalence (or as a percentage of total secondary osteons) of ≥ 1%. We present a quantitative histological method that can positively discriminate human bone from nonprimate mammalian bone in archaeological contexts.
Topics: Animals; Humans; Haversian System; Prevalence; Mammals; Histological Techniques; Primates
PubMed: 38394068
DOI: 10.1371/journal.pone.0298029 -
Tissue Engineering. Part A Jul 2014Vascularization of an artificial graft represents one of the most significant challenges facing the field of bone tissue engineering. Over the past decade, strategies to...
Vascularization of an artificial graft represents one of the most significant challenges facing the field of bone tissue engineering. Over the past decade, strategies to vascularize artificial scaffolds have been intensively evaluated using osteoinductive calcium phosphate (CaP) biomaterials in animal models. In this work, we observed that CaP-based biomaterials implanted into rat calvarial defects showed remarkably accelerated formation and mineralization of new woven bone in defects in the initial stages, at a rate of ∼60 μm/day (0.8 mg/day), which was considerably higher than normal bone growth rates (several μm/day, 0.1 mg/day) in implant-free controls of the same age. Surprisingly, we also observed histological evidence of primary osteon formation, indicated by blood vessels in early-region fibrous tissue, which was encapsulated by lamellar osteocyte structures. These were later fully replaced by compact bone, indicating complete regeneration of calvarial bone. Thus, the CaP biomaterial used here is not only osteoinductive, but vasculogenic, and it may have contributed to the bone regeneration, despite an absence of osteons in normal rat calvaria. Further investigation will involve how this strategy can regulate formation of vascularized cortical bone such as by control of degradation rate, and use of models of long, dense bones, to more closely approximate repair of human cortical bone.
Topics: Animals; Biocompatible Materials; Bone and Bones; Calcium Phosphates; Chitosan; Haversian System; Humans; Implants, Experimental; Male; Rats, Wistar; Skull; Wound Healing
PubMed: 24460696
DOI: 10.1089/ten.TEA.2013.0696 -
Journal of Forensic Sciences Mar 2012Distinguishing between human and nonhuman bone is important in forensic anthropology and archeology when remains are fragmentary and DNA cannot be obtained. Histological...
Distinguishing between human and nonhuman bone is important in forensic anthropology and archeology when remains are fragmentary and DNA cannot be obtained. Histological examination of bone is affordable and practical in such situations. This study suggests using osteon circularity to distinguish human bone fragments and hypothesizes that osteons will more closely resemble a perfect circle in nonhumans than in humans. Standard histological methods were used, and circularity was determined using an image analysis program, where circularity was controlled for by Haversian canal measurements. Homogeneity was first tested for multiple variables within human and nonhuman samples. No significant differences were found between human sexes (p = 0.657) or among nonhuman species (p = 0.553). Significant differences were found among intraskeletal elements of both humans (p = 0.016) and nonhumans (p = 0.013) and between pooled samples of humans and nonhumans (p < 0.001). Results of this study indicate that osteon circularity can be used to distinguish between fragmented human and nonhuman long bone.
Topics: Aged; Analysis of Variance; Animals; Bone and Bones; Deer; Dogs; Female; Forensic Anthropology; Haversian System; Humans; Image Processing, Computer-Assisted; Male; Microscopy; Middle Aged; Species Specificity; Swine
PubMed: 22103892
DOI: 10.1111/j.1556-4029.2011.01973.x -
Journal of Biomechanical Engineering Feb 1998Microcracks have been associated with age-related bone tissue fragility and fractures. The objective of this study was to develop a simple osteonal cortical bone model...
Microcracks have been associated with age-related bone tissue fragility and fractures. The objective of this study was to develop a simple osteonal cortical bone model and apply linear elastic fracture mechanics theory to understand the micromechanics of the fracture process in osteonal cortical bone and its dependence on material properties. The linear fracture mechanics of our composite model of cortical bone, consisting of an osteon and interstitial bone tissue, was characterized in terms of a stress intensity factor (SIF) near the tip of a microcrack. The interaction between a microcrack and an osteon was studied for different types of osteons and various spacing between the crack and the osteon. The results of the analysis indicate that the fracture mechanics of osteonal cortical bone is dominated by the modulus ratio between the osteon and interstitial bone tissue: A soft osteon promotes microcrack propagation toward the osteon (and cement line) while a stiff one repels the microcrack from the osteon (and cement line). These findings suggest that newly formed, low-stiffness osteons may toughen cortical bone tissue by promoting crack propagation toward osteons. A relatively accurate empirical formula also was obtained to provide an easy estimation of the influence of osteons on the stress intensity factor.
Topics: Biomechanical Phenomena; Bone Density; Bone Remodeling; Connective Tissue; Elasticity; Fracture Healing; Fractures, Spontaneous; Haversian System; Humans; Models, Theoretical; Tensile Strength
PubMed: 9675689
DOI: 10.1115/1.2834290