Exploratory Full-Field Strain Analysis of Regenerated Bone Tissue from Osteoinductive Biomaterials

Biomaterials for bone regeneration are constantly under development, and their application in critical-sized defects represents a promising alternative to bone grafting techniques. However, the ability of all these materials to produce bone mechanically comparable with the native tissue remains unclear. This study aims to explore the full-field strain evolution in newly formed bone tissue produced in vivo by different osteoinductive strategies, including delivery systems for BMP-2 release. In situ high-resolution X-ray micro-computed tomography (microCT) and digital volume correlation (DVC) were used to qualitatively assess the micromechanics of regenerated bone tissue. Local strain in the tissue was evaluated in relation to the different bone morphometry and mineralization for specimens (n = 2 p/treatment) retrieved at a single time point (10 weeks in vivo). Results indicated a variety of load-transfer ability for the different treatments, highlighting the mechanical adaptation of bone structure in the early stages of bone healing. Although exploratory due to the limited sample size, the findings and analysis reported herein suggest how the combination of microCT and DVC can provide enhanced understanding of the micromechanics of newly formed bone produced in vivo, with the potential to inform further development of novel bone regeneration approaches.

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Cellularizing hydrogel-based scaffolds to repair bone tissue: How to create a physiologically relevant micro-environment?

Journal of Tissue Engineering ◽

10.1177/2041731417712073 ◽

2017 ◽

Vol 8 ◽

pp. 204173141771207 ◽

Cited By ~ 28

Author(s):

Mathieu Maisani ◽

Daniele Pezzoli ◽

Olivier Chassande ◽

Diego Mantovani

Keyword(s):

Bone Regeneration ◽

Bone Tissue ◽

Bone Repair ◽

Critical Issue ◽

Bone Defects ◽

Bone Tissue Regeneration ◽

Differentiation Potential ◽

Promising Alternative

Tissue engineering is a promising alternative to autografts or allografts for the regeneration of large bone defects. Cell-free biomaterials with different degrees of sophistication can be used for several therapeutic indications, to stimulate bone repair by the host tissue. However, when osteoprogenitors are not available in the damaged tissue, exogenous cells with an osteoblast differentiation potential must be provided. These cells should have the capacity to colonize the defect and to participate in the building of new bone tissue. To achieve this goal, cells must survive, remain in the defect site, eventually proliferate, and differentiate into mature osteoblasts. A critical issue for these engrafted cells is to be fed by oxygen and nutrients: the transient absence of a vascular network upon implantation is a major challenge for cells to survive in the site of implantation, and different strategies can be followed to promote cell survival under poor oxygen and nutrient supply and to promote rapid vascularization of the defect area. These strategies involve the use of scaffolds designed to create the appropriate micro-environment for cells to survive, proliferate, and differentiate in vitro and in vivo. Hydrogels are an eclectic class of materials that can be easily cellularized and provide effective, minimally invasive approaches to fill bone defects and favor bone tissue regeneration. Furthermore, by playing on their composition and processing, it is possible to obtain biocompatible systems with adequate chemical, biological, and mechanical properties. However, only a good combination of scaffold and cells, possibly with the aid of incorporated growth factors, can lead to successful results in bone regeneration. This review presents the strategies used to design cellularized hydrogel-based systems for bone regeneration, identifying the key parameters of the many different micro-environments created within hydrogels.

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Heidelberg-mCT-Analyzer: a novel method for standardized microcomputed-tomography-guided evaluation of scaffold properties in bone and tissue research

Royal Society Open Science ◽

10.1098/rsos.150496 ◽

2015 ◽

Vol 2 (11) ◽

pp. 150496 ◽

Cited By ~ 10

Author(s):

Fabian Westhauser ◽

Christian Weis ◽

Melanie Hoellig ◽

Tyler Swing ◽

Gerhard Schmidmaier ◽

...

Keyword(s):

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Three Dimensional ◽

Characteristic Parameter ◽

Micro Computed Tomography ◽

Mineral Density ◽

Independent Analysis ◽

Scaffold Properties

Bone tissue engineering and bone scaffold development represent two challenging fields in orthopaedic research. Micro-computed tomography (mCT) allows non-invasive measurement of these scaffolds’ properties in vivo . However, the lack of standardized mCT analysis protocols and, therefore, the protocols’ user-dependency make interpretation of the reported results difficult. To overcome these issues in scaffold research, we introduce the Heidelberg-mCT-Analyzer. For evaluation of our technique, we built 10 bone-inducing scaffolds, which underwent mCT acquisition before ectopic implantation (T0) in mice, and at explantation eight weeks thereafter (T1). The scaffolds’ three-dimensional reconstructions were automatically segmented using fuzzy clustering with fully automatic level-setting. The scaffold itself and its pores were then evaluated for T0 and T1. Analysing the scaffolds’ characteristic parameter set with our quantification method showed bone formation over time. We were able to demonstrate that our algorithm obtained the same results for basic scaffold parameters (e.g. scaffold volume, pore number and pore volume) as other established analysis methods. Furthermore, our algorithm was able to analyse more complex parameters, such as pore size range, tissue mineral density and scaffold surface. Our imaging and post-processing strategy enables standardized and user-independent analysis of scaffold properties, and therefore is able to improve the quantitative evaluations of scaffold-associated bone tissue-engineering projects.

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Bone Regeneration Capacity of Newly Developed Uncalcined/Unsintered Hydroxyapatite and Poly-l-lactide-co-glycolide Sheet in Maxillofacial Surgery: An In Vivo Study

Nanomaterials ◽

10.3390/nano11010022 ◽

2020 ◽

Vol 11 (1) ◽

pp. 22

Author(s):

Huy Xuan Ngo ◽

Quang Ngoc Dong ◽

Yunpeng Bai ◽

Jingjing Sha ◽

Shinji Ishizuka ◽

...

Keyword(s):

Bone Regeneration ◽

Reconstructive Surgery ◽

Early Stage ◽

Maxillofacial Surgery ◽

Male Rats ◽

Regeneration Ability ◽

Sprague Dawley ◽

Micro Computed Tomography ◽

Rat Mandible

Uncalcined/unsintered hydroxyapatite and poly-l-lactide-co-glycolide (u-HA/PLLA/PGA) is a new bioresorbable nanomaterial with superior characteristics compared with current bioresorbable materials, including appropriate mechanical properties, outstanding bioactive/osteoconductive features, and remarkably shorter resorption time. Nevertheless, the bone regeneration characteristics of this nanomaterial have not been evaluated in maxillofacial reconstructive surgery. In this study, we used a rat mandible model to assess the bone regeneration ability of u-HA/PLLA/PGA material, compared with uncalcined/unsintered hydroxyapatite and poly-l-lactide acid (u-HA/PLLA) material, which has demonstrated excellent bone regenerative ability. A 4-mm-diameter defect was created at the mandibular angle area in 28 Sprague Dawley male rats. The rats were divided into three groups: u-HA/PLLA/PGA (u-HA/PLLA/PGA graft + defect), u-HA/PLLA (u-HA/PLLA graft + defect), and sham control (defect alone). At 1, 3, 8, and 16 weeks after surgeries, the rats were sacrificed and assessed by micro-computed tomography, histological analysis with hematoxylin and eosin staining, and immunohistochemical analyses. The results confirmed that the accelerated bone bioactive/regenerative osteoconduction of u-HA/PLLA/PGA was comparable with that of u-HA/PLLA in the rat mandible model. Furthermore, this new regenerative nanomaterial was able to more rapidly induce bone formation in the early stage and had great potential for further clinical applications in maxillofacial reconstructive surgery.

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Mineralized Nanofibers for Bone Tissue Engineering

Biomedical Engineering ◽

10.4018/978-1-5225-3158-6.ch020 ◽

2018 ◽

pp. 461-475 ◽

Cited By ~ 1

Author(s):

Ozan Karaman

Keyword(s):

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Regeneration ◽

Bone Tissue ◽

Three Dimensional ◽

Bone Grafts ◽

Tissue Engineering Scaffolds ◽

Promising Alternative ◽

Biomimetic Scaffolds

The limitation of orthopedic fractures and large bone defects treatments has brought the focus on fabricating bone grafts that could enhance ostegenesis and vascularization in-vitro. Developing biomimetic materials such as mineralized nanofibers that can provide three-dimensional templates of the natural bone extracellular-matrix is one of the most promising alternative for bone regeneration. Understanding the interactions between the structure of the scaffolds and cells and therefore the control cellular pathways are critical for developing functional bone grafts. In order to enhance bone regeneration, the engineered scaffold needs to mimic the characteristics of composite bone ECM. This chapter reviews the fabrication of and fabrication techniques for fabricating biomimetic bone tissue engineering scaffolds. In addition, the chapter covers design criteria for developing the scaffolds and examples of enhanced osteogenic differentiation outcomes by fabricating biomimetic scaffolds.

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In vivo bone regeneration assessment of offset and gradient melt electrowritten (MEW) PCL scaffolds

Biomaterials Research ◽

10.1186/s40824-020-00196-1 ◽

2020 ◽

Vol 24 (1) ◽

Author(s):

Naghmeh Abbasi ◽

Ryan S. B. Lee ◽

Saso Ivanovski ◽

Robert M. Love ◽

Stephen Hamlet

Keyword(s):

Bone Regeneration ◽

Size Structure ◽

Three Dimensional ◽

Immunohistochemical Analysis ◽

Repair Process ◽

Micro Computed Tomography ◽

Calvarial Defects ◽

Promising Solution ◽

Poly Caprolactone

Abstract Background Biomaterial-based bone tissue engineering represents a promising solution to overcome reduced residual bone volume. It has been previously demonstrated that gradient and offset architectures of three-dimensional melt electrowritten poly-caprolactone (PCL) scaffolds could successfully direct osteoblast cells differentiation toward an osteogenic lineage, resulting in mineralization. The aim of this study was therefore to evaluate the in vivo osteoconductive capacity of PCL scaffolds with these different architectures. Methods Five different calcium phosphate (CaP) coated melt electrowritten PCL pore sized scaffolds: 250 μm and 500 μm, 500 μm with 50% fibre offset (offset.50.50), tri layer gradient 250–500-750 μm (grad.250top) and 750–500-250 μm (grad.750top) were implanted into rodent critical-sized calvarial defects. Empty defects were used as a control. After 4 and 8 weeks of healing, the new bone was assessed by micro-computed tomography and immunohistochemistry. Results Significantly more newly formed bone was shown in the grad.250top scaffold 8 weeks post-implantation. Histological investigation also showed that soft tissue was replaced with newly formed bone and fully covered the grad.250top scaffold. While, the bone healing did not happen completely in the 250 μm, offset.50.50 scaffolds and blank calvaria defects following 8 weeks of implantation. Immunohistochemical analysis showed the expression of osteogenic markers was present in all scaffold groups at both time points. The mineralization marker Osteocalcin was detected with the highest intensity in the grad.250top and 500 μm scaffolds. Moreover, the expression of the endothelial markers showed that robust angiogenesis was involved in the repair process. Conclusions These results suggest that the gradient pore size structure provides superior conditions for bone regeneration.

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Collagen Scaffolds Containing Hydroxyapatite-CaO Fiber Fragments for Bone Tissue Engineering

Polymers ◽

10.3390/polym12051174 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1174 ◽

Cited By ~ 1

Author(s):

Shiao-Wen Tsai ◽

Sheng-Siang Huang ◽

Wen-Xin Yu ◽

Yu-Wei Hsu ◽

Fu-Yin Hsu

Keyword(s):

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Regeneration ◽

Bone Tissue ◽

Drug Loading ◽

Sol Gel ◽

Regeneration Ability ◽

Burst Release ◽

Electrospinning Technique

Collagen (COL) and hydroxyapatite (HAp) are the major components of bone, therefore, COL-HAp composites have been widely used as bone substitutes to promote bone regeneration. We have reported that HAp-CaO fibers (HANFs), which were fabricated by a sol-gel route followed by an electrospinning technique, possessed good drug-loading efficiency and limited the burst release of tetracycline. In the present study, we used HANF fragments to evaluate the effects of COL-HANF scaffolds on MG63 osteoblast-like cell behaviors. COL-HANF composite scaffolds in which the average diameter of HANFs was approximately 461 ± 186 nm were fabricated by a freeze-drying process. The alkaline phosphatase activity and the protein expression levels of OCN and BSP showed that compared with COL alone, the COL-HANF scaffold promoted the differentiation of MG63 osteoblast-like cells. In addition, the bone regeneration ability of the COL-HANF scaffold was examined by using a rabbit condylar defect model in vivo. The COL-HANF scaffold was biodegradable and promoted bone regeneration eight weeks after the operation. Hence, we concluded that the COL-HANF scaffold has potential as a bone graft for bone tissue engineering.

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Demineralized bone matrix-based microcarrier scaffold favors vascularized large bone regeneration in vivo in a rat model

Journal of Biomaterials Applications ◽

10.1177/0885328218784370 ◽

2018 ◽

Vol 33 (2) ◽

pp. 182-195 ◽

Cited By ~ 4

Author(s):

Qiannan Li ◽

Wenjie Zhang ◽

Guangdong Zhou ◽

Yilin Cao ◽

Wei Liu ◽

...

Keyword(s):

Computed Tomography ◽

Stem Cells ◽

Bone Marrow ◽

Bone Regeneration ◽

Demineralized Bone Matrix ◽

Bone Matrix ◽

Matrix Group ◽

Micro Computed Tomography ◽

Demineralized Bone

Insufficient neo-vascularization of in vivo implanted cell-seeded scaffold remains a major bottleneck for clinical translation of engineered bone formation. Demineralized bone matrix is an ideal bone scaffold for bone engineering due to its structural and biochemical components similar to those of native bone. We hypothesized that the microcarrier form of demineralized bone matrix favors ingrowth of vessels and bone regeneration upon in vivo implantation. In this study, a rat model of femoral vessel pedicle-based bone engineering was employed by filling the demineralized bone matrix scaffolds inside a silicone chamber that surrounded the vessel pedicles, and to compare the efficiency of vascularized bone regeneration between microcarrier demineralized bone matrix and block demineralized bone matrix. The results showed that bone marrow stem cells better adhered to microcarrier demineralized bone matrix and produced more extracellular matrices during in vitro culture. After in vivo implantation, microcarrier demineralized bone matrix seeded with bone marrow stem cells formed relatively more bone tissue than block demineralized bone matrix counterpart at three months upon histological examination. Furthermore, micro-computed tomography three-dimensional reconstruction showed that microcarrier demineralized bone matrix group regenerate significantly better and more bone tissues than block demineralized bone matrix both qualitatively and quantitatively (p < 0.05). Moreover, micro-computed tomography reconstructed angiographic images also demonstrated significantly enhanced tissue vascularization in microcarrier demineralized bone matrix group than in block demineralized bone matrix group both qualitatively and quantitatively (p < 0.05). Anti-CD31 immunohistochemical staining of (micro-) vessels and semi-quantitative analysis also evidenced enhanced vascularization of regenerated bone in microcarrier demineralized bone matrix group than in block demineralized bone matrix group (p < 0.05). In conclusion, the microcarrier form of demineralized bone matrix is an ideal bone regenerative scaffold due to its advantages of osteoinductivity and vascular induction, two essentials for in vivo bone regeneration.

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An Innovative Tool to Measure Human Skin Strain Distribution in Vivo using Motion Capture and Delaunay Mesh

Journal of Mechanics ◽

10.1017/jmech.2012.34 ◽

2012 ◽

Vol 28 (2) ◽

pp. 309-317 ◽

Cited By ~ 13

Author(s):

J. Mahmud ◽

S. L. Evans ◽

C. A. Holt

Keyword(s):

Finite Elements ◽

Human Skin ◽

Motion Capture ◽

Strain Distribution ◽

Field Strain ◽

Full Field ◽

Skin Deformation ◽

Deformation Mechanics ◽

Delaunay Mesh

AbstractSkin has a complex structure and its deformation mechanics is still not well defined. In the study of skin biomechanics, the stretch ratio, λ, is an important property, which is determined using strain data. This paper attempts to develop a novel tool by integrating experimental-numerical approach to measure full-field strain distribution of human skin in vivo. Skin deformation in vivo was measured using motion capture system, (which is not a full-field measuring tool) and then by constructing finite elements, its full-field strain contour is produced. The experimental procedure starts by attaching a set of reflective markers onto the skin at the forearm of healthy volunteers. Skin deformation is induced by pulling a nylon filament attached with a loading tab. Three infrared cameras are used to capture the movement of markers during load application. QTM (Qualisys, Sweden) software is used to track markers trajectories and generate data consisting of 3-dimensional markers coordinate. The initial capture is set as the reference marker positions (undeformed skin) and the subsequent images represent the deformed skin relative to the initial. Representing markers as nodes, finite elements are constructed by adjoining three adjacent markers using Delaunay mesh. Strains were deduced from the strain displacement matrix and measured for three subjects at three loading directions. The results are in fair agreement with those obtained by others. The method and output provide a useful addition to understanding skin deformation.

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Trabecular and cortical bone are unaltered in response to chronic lipopolysaccharide exposure via osmotic pumps in male and female CD-1 mice

PLoS ONE ◽

10.1371/journal.pone.0243933 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0243933

Author(s):

Kirsten N. Bott ◽

Jenalyn L. Yumol ◽

Elena M. Comelli ◽

Panagiota Klentrou ◽

Sandra J. Peters ◽

...

Keyword(s):

Cortical Bone ◽

Bone Structure ◽

Low Grade ◽

Micro Computed Tomography ◽

Mineral Density ◽

Potent Inducer ◽

Male And Female ◽

Osmotic Pumps ◽

Longitudinal Response

Chronic low-grade inflammation has been identified as an underlying cause of many diseases including osteoporosis. Lipopolysaccharide (LPS) is a potent inducer of the inflammatory response that can negatively affect bone outcomes by upregulating bone resorption and inhibiting bone formation. The objective of this study was to assess the longitudinal response of trabecular and cortical bone structure and bone mineral density to LPS continuously administered for 12 weeks in male and female CD-1 mice. Mice were assigned to one of four LPS groups at 8-weeks of age: placebo (0.0 μg/d), low (0.9 μg/d), mid (3.6 μg/d) and high (14.4 μg/d) dose. Trabecular and cortical bone outcomes were measured at 8, 12, 16, and 20 weeks of age using in vivo micro-computed tomography. The anticipated serum LPS dose-dependent response was not observed. Therefore, the low, mid, and high LPS groups were combined for analysis. Compared to the placebo group, endpoint serum LPS was elevated in both males (p < 0.05) and females (p < 0.05) when all LPS treatment groups were combined. However, there was no significant change in trabecular or cortical bone outcomes in the combined LPS groups compared to the placebo following the 12-week LPS intervention for either sex. This suggests that although serum LPS was elevated following the 12-week LPS intervention, the dosages administered using the osmotic pumps was not sufficient to negatively impact trabecular or cortical bone outcomes in either male or female CD-1 mice.

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Longitudinal in vivo micro-CT-based approach allows spatio-temporal characterization of fracture healing patterns and assessment of biomaterials in mouse femur defect models

10.1101/2020.10.02.324061 ◽

2020 ◽

Author(s):

Esther Wehrle ◽

Duncan C Tourolle né Betts ◽

Gisela A Kuhn ◽

Erica Floreani ◽

Malavika H Nambiar ◽

...

Keyword(s):

Bone Regeneration ◽

Healing Process ◽

Micro Ct ◽

Micro Computed Tomography ◽

Collagen Scaffolds ◽

Non Union ◽

Spatio Temporal ◽

Large Bone

AbstractThorough preclinical evaluation of novel biomaterials for treatment of large bone defects is essential prior to clinical application. Using in vivo micro-computed tomography (micro-CT) and mouse femoral defect models with different defect sizes, we were able to detect spatio-temporal healing patterns indicative of physiological and impaired healing in three defect sub-volumes and the adjacent cortex. The time-lapsed in vivo micro-CT-based approach was then applied to evaluate the bone regeneration potential of biomaterials using collagen and BMP-2 as test materials. Both collagen and BMP-2 treatment led to distinct changes in bone turnover in the different healing phases. Despite increased periosteal bone formation, 87.5% of the defects treated with collagen scaffolds resulted in non-unions. Additional BMP-2 application significantly accelerated the healing process and increased the union rate to 100%. This study further shows potential of time-lapsed in vivo micro-CT for capturing spatio-temporal deviations preceding non-union formation and how this can be prevented by application of biomaterials.This study therefore supports the application of longitudinal in vivo micro-CT for discrimination of normal and disturbed healing patterns and for the spatio-temporal characterization of the bone regeneration capacity of biomaterials.

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