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Bone Reports Jun 2017Bone is a composite material with five distinct structural levels: collagen molecules, mineralized collagen fibrils, lamellae, osteon and whole bone. However, most...
Bone is a composite material with five distinct structural levels: collagen molecules, mineralized collagen fibrils, lamellae, osteon and whole bone. However, most fracture testing methods have been limited to the macroscopic scale and there is a need for advanced characterization methods to assess toughness at the osteon level and below. The goal of this investigation is to present a novel framework to measure the fracture properties of bone at the microscopic scale using scratch testing. A rigorous experimental protocol is articulated and applied to examine cortical bone specimens from porcine femurs. The observed fracture behavior is very complex: we observe a strong anisotropy of the response with toughening mechanisms and a competition between plastic flow and brittle fracture. The challenge consists then in applying nonlinear fracture mechanics methods such as the -integral or the energetic Size Effect Law to quantify the fracture toughness in a rigorous fashion. Our result suggests that mixed-mode fracture is instrumental in determining the fracture resistance. There is also a pronounced coupling between fracture and elasticity. Our methodology opens the door to fracture assessment at multiple structural levels, microscopic and potentially nanometer length scale, due to the scalability of scratch tests.
PubMed: 28377977
DOI: 10.1016/j.bonr.2016.12.001 -
Journal of Advanced Periodontology &... 2020The present study aimed to evaluate the osteopromoting ability of human tooth powder and compare it to a bovine xenograft, a synthetic material, and the DFDBA allograft.
Comparison of osteopromoting ability of human tooth powder with the demineralized freeze-dried bone allograft, a bovine xenograft, and a synthetic graft: An in vitro study.
BACKGROUND
The present study aimed to evaluate the osteopromoting ability of human tooth powder and compare it to a bovine xenograft, a synthetic material, and the DFDBA allograft.
METHODS
In this in vitro study, 30 teeth without caries, inflammation, and infection, which had been extracted for orthodontic reasons, were collected. The crowns were removed, pulpectomy was carried out, and the samples were ground to a powder with particles <500 µm. Osteoblast-like cells of MG-63 were cultured with the tooth powder, Cerabone, DFDBA, and Osteon II. Cell proliferation was assessed by the MTT assay at 24- and 72-hour intervals. The alizarin red test was carried out after three and five days. The alkaline phosphatase level was measured after 24, 48, and 72 hours to assess the osteoblastic activity. The results were analyzed with one-way ANOVA.
RESULTS
According to the MTT assay, all the materials exhibited a higher proliferation rate than the control group in 24 hours. In 72 hours, DFDBA had the lowest cell proliferation rate at concentrations of 40 and 80 mg/mL. DFDBA and the positive control group were able to create calcified nodules by the alizarin red test. At the 48- and 72-hour intervals, DFDBA had the lowest alkaline phosphatase activity at a concentration of 40 mg/mL. At the 72-hour interval, bovine xenograft had the highest alkaline phosphatase level, followed by the synthetic material and tooth powder.
CONCLUSION
The tooth powder was able to increase cell proliferation in comparison with the bovine xenograft, the synthetic graft, and the DFDBA. However, its osteopromoting ability was less than that of the osteogenic materials.
PubMed: 35919308
DOI: 10.34172/japid.2020.005 -
Journal of Biological Engineering Jul 2023Modular tissue engineering (MTE) is a novel "bottom-up" approach that aims to mimic complex tissue microstructural features. The constructed micromodules are assembled...
BACKGROUND
Modular tissue engineering (MTE) is a novel "bottom-up" approach that aims to mimic complex tissue microstructural features. The constructed micromodules are assembled into engineered biological tissues with repetitive functional microunits and form cellular networks. This is emerging as a promising strategy for reconstruction of biological tissue.
RESULTS
Herein, we constructed a micromodule for MTE and developed engineered osteon-like microunits by inoculating human-derived umbilical cord mesenchymal stem cells (HUMSCs) onto nHA/PLGA microspheres with surface modification of dual growth factors (BMP2/bFGF). By evaluating the results of proliferation and osteogenic differentiation ability of HUMSCs in vitro, the optimal ratio of the dual growth factor (BMP2/bFGF) combination was derived as 5:5. In vivo assessments showed the great importance of HUMSCs for osteogneic differentiation. Ultimately, direct promotion of early osteo-differentiation manifested as upregulation of Runx-2 gene expression. The vascularization capability was evaluated by tube formation assays, demonstrating the importance of HUMSCs in the microunits for angiogenesis.
CONCLUSIONS
The modification of growth factors and HUMSCs showed ideal biocompatibility and osteogenesis combined with nHA/PLGA scaffolds. The micromodules constructed in the current study provide an efficient stem cell therapy strategy for bone defect repair.
PubMed: 37430290
DOI: 10.1186/s13036-023-00360-w -
World Journal of Stem Cells Nov 2015To evaluate adhesion, proliferation and differentiation of human dental pulp stem cells (hDPSCs) on four commercially available scaffold biomaterials.
AIM
To evaluate adhesion, proliferation and differentiation of human dental pulp stem cells (hDPSCs) on four commercially available scaffold biomaterials.
METHODS
hDPSCs were isolated from human dental pulp tissues of extracted wisdom teeth and established in stem cell growth medium. hDPSCs at passage 3-5 were seeded on four commercially available scaffold biomaterials, SureOss (Allograft), Cerabone (Xenograft), PLLA (Synthetic), and OSTEON II Collagen (Composite), for 7 and 14 d in osteogenic medium. Cell adhesion and morphology to the scaffolds were evaluated by scanning electron microscopy (SEM). Cell proliferation and differentiation into osteogenic lineage were evaluated using DNA counting and alkaline phosphatase (ALP) activity assay, respectively.
RESULTS
All scaffold biomaterials except SureOss (Allograft) supported hDPSC adhesion, proliferation and differentiation. hDPSCs seeded on PLLA (Synthetic) scaffold showed the highest cell proliferation and attachment as indicated with both SEM and DNA counting assay. Evaluating the osteogenic differentiation capability of hDPSCs on different scaffold biomaterials with ALP activity assay showed high level of ALP activity on cells cultured on PLLA (Synthetic) and OSTEON II Collagen (Composite) scaffolds. SEM micrographs also showed that in the presence of Cerabone (Xenograft) and OSTEON II Collagen (Composite) scaffolds, the hDPSCs demonstrated the fibroblastic phenotype with several cytoplasmic extension, while the cells on PLLA scaffold showed the osteoblastic-like morphology, round-like shape.
CONCLUSION
PLLA scaffold supports adhesion, proliferation and osteogenic differentiation of hDPSCs. Hence, it may be useful in combination with hDPSCs for cell-based reconstructive therapy.
PubMed: 26640621
DOI: 10.4252/wjsc.v7.i10.1215 -
Iranian Journal of Basic Medical... Nov 2020We investigated the role of various biomaterials on cell viability and in healing of an experimentally induced femoral bone hole model in rats.
Role of organic and ceramic biomaterials on bone healing and regeneration: An experimental study with significant value in translational tissue engineering and regenerative medicine.
OBJECTIVES
We investigated the role of various biomaterials on cell viability and in healing of an experimentally induced femoral bone hole model in rats.
MATERIALS AND METHODS
Cell viability and cytotoxicity of gelatin (Gel; 50 µg/µl), chitosan (Chi; 20 µg/µl), hydroxyapatite (HA; 50 µg/µl), nanohydroxyapatite (nHA; 10 µg/µl), three-calcium phosphate (TCP; 50 µg/µl) and strontium carbonate (Sr; 10 µg/µl) were evaluated on hADSCs via MTT assay. femoral drill-bone hole model was produced in rats that were either left untreated or treated with autograft, Gel, Chi, HA, nHA, TCP and Sr, respectively. The animals were euthanized after 30 days. Their bone holes were evaluated by gross-pathology, histopathology, SEM and radiography. Also, their dry matter, bone ash and mineral density were measured.
RESULTS
Both the Gel and Chi showed cytotoxicity, while nHA had no role on cytotoxicity and cell-viability. All the HA, TCP and Sr significantly improved cell viability when compared to controls (0.05). Both the Gel and Chi had no role on osteoconduction and osteoinduction. Compared to HA, nHA showed superior role in increasing new bone formation, mineral density and ash (0.05). In contrast to HA and nHA, both the TCP and Sr showed superior morphological, radiographical and biochemical properties on bone healing (0.05). TCP and Sr showed the most effective osteoconduction and osteoinduction, respectively. In the Sr group, the most mature type of osteons formed.
CONCLUSION
Various biomaterials have different efficacy during bone regeneration. TCP was found to be the best material for osteoconduction and Sr for osteoinduction.
PubMed: 33235700
DOI: 10.22038/ijbms.2020.46228.10707 -
Journal of Orthopaedic Research :... Jun 2022The purpose of this study was to determine the efficacy of highly concentrated tricalcium phosphate (TCP) biocomposite screws on local bone formation in a rabbit model...
The purpose of this study was to determine the efficacy of highly concentrated tricalcium phosphate (TCP) biocomposite screws on local bone formation in a rabbit model of osteoporosis induced by bilateral ovariohysterectomy (OHE). Fourteen 24-week-old female New Zealand rabbits (weight, 3-3.5 kg) were divided into two groups: (1) OHE and biodegradable poly(lactic-co-glycolic acid) (PLGA) without ß-TCP plate or screw insertion (OHE/Bio ScRew [BSR]) group and (2) OHE and biocomposite PLGA with highly concentrated ß-TCP plate and screw insertion (OHE/highly concentrated ß-triCalcium phosphate [HCCP]). Both groups underwent bilateral OHE and had two different types of screws and plates inserted at the proximal tibia. Bilateral tibiae were extracted at 25 weeks post-OHE. The extracted tibiae were scanned with ex vivo microcomputed tomography (micro-CT). Parameters including bone mineral density (BMD), trabecular bone volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb. Th), and trabecular separation (Tb. Sp) were evaluated after staining the tibial samples with hematoxylin and eosin (H&E) and Masson's trichrome. We then performed pathological assessments. Micro-CT images revealed improved new bone formation near the implant in the OHE/HCCP group with higher values of BMD, BV/TV, and Tb.N but lower values of Tb. Th and Tb. Sp than the OHE/BSR group. Analyses of H&E and Masson's trichrome staining showed better new bone formation around the implant in the OHE/HCCP group than in the OHE/BSR group. The use of highly concentrated TCP biocomposite screw and plate might improve local bone formation and facilitate osteoconductivity in an osteoporotic rabbit model.
Topics: Animals; Bone Density; Bone Screws; Calcium Phosphates; Female; Osteogenesis; Osteoporosis; Rabbits; X-Ray Microtomography
PubMed: 34432337
DOI: 10.1002/jor.25171 -
Anais Da Academia Brasileira de Ciencias Sep 2019Abstract: Riostegotherium yanei from the Itaboraí Basin, Brazil, is the oldest known Xenarthra. This paper aims to describe the internal morphology of the osteoderms...
Abstract: Riostegotherium yanei from the Itaboraí Basin, Brazil, is the oldest known Xenarthra. This paper aims to describe the internal morphology of the osteoderms of Riostegotherium yanei from the perspective of histology and micro-CT approaches, expanding the available data on cingulate osteoderm microstructure. Seven osteoderms of R. yanei were used for the internal microstructure description and eight of Dasypus novemcinctus for comparison. The osteoderms of Riostegotherium yanei lacks the diploë-like structure typical of glyptodonts but has a three-layered structure composed of two layers of non-Haversian compact bone enclosing a central layer of primary and secondary osteons. This internal organization is distinct from other Astegotheriini of comparable age, but similar to Dasypus. The 3D reconstruction of Riostegotherium yanei revealed two patterns of internal organization. Pattern 1 of movable osteoderm is composed of large remodeled areas at the base and a more compact bone at the tongue; in Pattern 2 (both movable and buckler), the internal cavities are much smaller, more numerous, and more interconnected to each other. In one buckler osteoderm, the cavities are organized somewhat radially with a compact central region (Pattern 1). Pattern 1 of both movable and buckler osteoderms resemble that of Dasypus.
Topics: Animals; Bone and Bones; Brazil; Fossils; Xenarthra
PubMed: 31482940
DOI: 10.1590/0001-3765201920181290 -
Journal of Anatomy May 2011Osteon morphotype scores (MTSs) allow for quantification of mechanically important collagen/lamellar variations between secondary osteons when viewed in circularly...
Osteon morphotype scores (MTSs) allow for quantification of mechanically important collagen/lamellar variations between secondary osteons when viewed in circularly polarized ight (CPL). We recently modified the 6-point MTS method of Martin et al. (Martin RB, Gibson VA, Stover SM, Gibeling JC, Griffin LV (1996a) Osteonal structure in the equine third metacarpus. Bone 19, 165-71) and reported superiority of this modified method in correlating with 'tension' and 'compression' cortices of both chimpanzee proximal femoral diaphyses and diaphyses of other non-anthropoid bones that are loaded in habitual bending (Skedros et al. 2009, 2011). In these studies, the 'tension' and 'compression' cortices differed significantly in predominant collagen fiber orientation (CFO) based on weighted-mean gray levels (CFO/WMGLs) in CPL images. In chimpanzee femora, however, some osteons were difficult to score with the 6-point method; namely, 'hybrids' with peripherally bright 'hoops' and variability in alternating rings within the osteon wall. We hypothesized that some of these hybrids would be more prevalent in regions subject to torsion than bending. In this perspective the present study was aimed at expanding our 6-point scoring method (S-6-MTS) into two 12-point methods with six additional morphotypes that considered these hybrids. Three- and 4-point methods were also evaluated. We hypothesized that at least one of these other methods would out-perform the S-6-MTS in terms of accuracy, reliability, and interpreting torsion vs. bending load histories. Osteon morphotypes were quantified in CPL images from transverse sections of eight adult chimpanzee femora (neck, proximal diaphysis, mid-diaphysis), where the mid-diaphysis and base- and mid-neck locations have relatively more complex loading (e.g. torsion + bending) than the proximal diaphysis, where bending predominates. Correlation coefficients between CFO/WMGL and MTSs showed that the S-6-MTS method was either stronger or equivalent to the 12-point methods, and typically stronger than the 3- and 4-point methods for all load environments. In nearly all instances the S-6-MTS is more reliable and accurate when it is applied to cases where interpreting load history requires distinguishing habitual bending from torsion. Consequently, in studies of osteonal adaptations for these load histories the 3- and 4-point methods are not stronger correlates, and the extra time required to assign additional scores in the 12-point methods is both unnecessary and can be highly unreliable.
Topics: Adaptation, Physiological; Animals; Collagen; Femur; Haversian System; Microscopy, Polarization; Pan troglodytes; Stress, Mechanical; Weight-Bearing
PubMed: 21323667
DOI: 10.1111/j.1469-7580.2011.01348.x -
Bone Dec 2023Current clinical methods of bone health assessment depend to a great extent on bone mineral density (BMD) measurements. However, these methods only act as a proxy for...
Current clinical methods of bone health assessment depend to a great extent on bone mineral density (BMD) measurements. However, these methods only act as a proxy for bone strength and are often only carried out after the fracture occurs. Besides BMD, composition and tissue-level mechanical properties are expected to affect the whole bone's strength and toughness. While the elastic properties of the bone extracellular matrix (ECM) have been extensively investigated over the past two decades, there is still limited knowledge of the yield properties and their relationship to composition and architecture. In the present study, morphological, compositional and micropillar compression bone data was collected from patients who underwent hip arthroplasty. Femoral neck samples from 42 patients were collected together with anonymous clinical information about age, sex and primary diagnosis (coxarthrosis or hip fracture). The femoral neck cortex from the inferomedial region was analyzed in a site-matched manner using a combination of micromechanical testing (nanoindentation, micropillar compression) together with micro-CT and quantitative polarized Raman spectroscopy for both morphological and compositional characterization. Mechanical properties, as well as the sample-level mineral density, were constant over age. Only compositional properties demonstrate weak dependence on patient age: decreasing mineral to matrix ratio (p = 0.02, R = 0.13, 2.6 % per decade) and increasing amide I sub-peak ratio I/I (p = 0.04, R = 0.11, 1.5 % per decade). The patient's sex and diagnosis did not seem to influence investigated bone properties. A clear zonal dependence between interstitial and osteonal cortical zones was observed for compositional and elastic bone properties (p < 0.0001). Site-matched microscale analysis confirmed that all investigated mechanical properties except yield strain demonstrate a positive correlation with the mineral fraction of bone. The output database is the first to integrate the experimentally assessed microscale yield properties, local tissue composition and morphology with the available patient clinical information. The final dataset was used for bone fracture risk prediction in-silico through the principal component analysis and the Naïve Bayes classification algorithm. The analysis showed that the mineral to matrix ratio, indentation hardness and micropillar yield stress are the most relevant parameters for bone fracture risk prediction at 70 % model accuracy (0.71 AUC). Due to the low number of samples, further studies to build a universal fracture prediction algorithm are anticipated with the higher number of patients (N > 200). The proposed classification algorithm together with the output dataset of bone tissue properties can be used for the future comparison of existing methods to evaluate bone quality as well as to form a better understanding of the mechanisms through which bone tissue is affected by aging or disease.
PubMed: 37769956
DOI: 10.1016/j.bone.2023.116920 -
Applied Bionics and Biomechanics 2022Cortical bone is a transversely isotropic material, and the mechanical properties may be related to the loading direction on the osteon. Therefore, analyzing the...
Cortical bone is a transversely isotropic material, and the mechanical properties may be related to the loading direction on the osteon. Therefore, analyzing the differences in the failure processes of cortical bone under different loading conditions is necessary to explore the measures for reducing the incidence of fracture. In this study, to investigate the effects of different loading directions on the fracture performance in the cortical bone, a numerical method that could simultaneously simulate the failure processes in the cortical bone structure under compression and bending loads was established based on continuum damage mechanics theory. The prediction accuracy and feasibility of the numerical method were first verified by comparing with the corresponding experimental results. Then, the differences in the failure process and fracture performance of the same cortical bone structure under compression and bending loads were investigated. The simulation results indicated that for the same structure, the slip-open failure mode appeared under compression load, and the crack propagated along a certain angle to the loading direction; the tension-open failure mode appeared under bending load, and the crack propagated along the direction perpendicular to the loading direction. Meanwhile, the fracture load was greater and the fracture time was later in the compression than in the bending condition. These phenomena stated that discrepant failure processes and fracture patterns occurred in the same cortical bone structure under different loading conditions. The main reason may be related to the tension-compression asymmetry and transversely isotropic characteristics in the cortical bone material. The fracture simulations in the cortical bone under different loading conditions could improve the prediction accuracy in bone biomechanics and provide the prevention method for cortical bone damage and fracture.
PubMed: 36439555
DOI: 10.1155/2022/3406984