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Kataoka T, Liu Z, Yamada I, Galindo TGP, Tagaya M. Surface functionalization of hydroxyapatite nanoparticles for biomedical applications. J Mater Chem B 2024; 12:6805-6826. [PMID: 38919049 DOI: 10.1039/d4tb00551a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
This review completely covers the various aspects of hydroxyapatite (HAp) nanoparticles and their role in different biological situations, and provides the surface and interface contents on (i) hydroxyapatite nanoparticles and their hybridization with organic molecules, (ii) surface designing of hydroxyapatite nanoparticles to provide their biocompatibility and photofunction, and (iii) coating technology of hydroxyapatite nanoparticles. In particular, we summarized how the HAp nanoparticles interact with the different ions and molecules and highlighted the potential for hybridization between HAp nanoparticles and organic molecules, which is driven by the interactions of the HAp nanoparticle surface ions with several functional groups of biological molecules. In addition, we highlighted the studies focusing on the interfacial interactions between the HAp nanoparticles and proteins for exploring the enhanced biocompatibility. Such studies focus on how these interactions affect the hydration layers and protein adsorption. However, the hydration layer state involves diverse molecular interactions that can alter the shape of the adsorbed proteins, thereby affecting cell adhesion and spreading on the surfaces. We also summarized the relationship between the surface properties of the HAp nanoparticles and the hydration layer. Furthermore, we spotlighted the cytocompatible photoluminescent probes that can be developed by designing HAp/organic nanohybrid structures. We then emphasized the importance of photofunctionalization in theranostics, which involves the integration of diagnostics and therapy based on the surface design of the HAp nanoparticles. Furthermore, the coating techniques using HAp nanoparticles and HAp nanoparticle/polymer composites were outlined for fusing base biomaterials with biological tissues. The advantages of HAp/biocompatible polymer composite coatings include the ability to effectively cover porous or irregularly shaped surfaces while controlling the thickness of the coating layer, and the addition of HAp nanoparticles to the polymer matrix improves the mechanical properties, increases the roughness, and forms the morphologies that mimic bone nanostructures. Therefore, the fundamental design of hydroxyapatite nanoparticles and their surfaces was suggested from various aspects for biomedical applications.
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Affiliation(s)
- Takuya Kataoka
- Faculty of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Zizhen Liu
- Department of Materials Science and Bioengineering, Graduate School of Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
- Research Fellow of the Japan Society for the Promotion of Science (DC), 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Iori Yamada
- Department of Materials Science and Bioengineering, Graduate School of Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
| | - Tania Guadalupe Peñaflor Galindo
- Department of General Education, National Institute of Technology, Nagaoka College, 888 Nishikatakai, Nagaoka, Niigata 940-8532, Japan
| | - Motohiro Tagaya
- Department of Materials Science and Bioengineering, Graduate School of Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
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Xiao P, Roy A, Wang X. In-silico simulation of nanoindentation on bone using a 2D cohesive finite element model. J Mech Behav Biomed Mater 2024; 151:106403. [PMID: 38237206 DOI: 10.1016/j.jmbbm.2024.106403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 02/03/2024]
Abstract
This study proposed and validated a 2D finite element (FE) model for conducting in-silico simulations of in-situ nanoindentation tests on mineralized collagen fibrils (MCF) and the extrafibrillar matrix (EFM) within human cortical bone. Initially, a multiscale cohesive FE model was developed by adapting a previous model of bone lamellae, encompassing both MCF and EFM. Subsequently, nanoindentation tests were simulated in-silico using this model, and the resulting predictions were compared to AFM nanoindentation test data to verify the model's accuracy. The FE model accurately predicted nanoindentation results under wet conditions, closely aligning with outcomes obtained from AFM nanoindentation tests. Specifically, it successfully mirrored the traction/separation curve, nanoindentation modulus, plastic energy dissipation, and plastic energy ratio obtained from AFM nanoindentation tests. Additionally, this in-silico model demonstrated its ability to capture alterations in nanoindentation properties caused by the removal of bound water, by considering corresponding changes in mechanical properties of the collagen phase and the interfaces among bone constituents. Notably, significant changes in the elastic modulus and plastic energy dissipation were observed in both MCF and EFM compartments of bone, consistent with observations in AFM nanoindentation tests. These findings indicate that the proposed in-silico model effectively captures the influence of ultrastructural changes on bone's mechanical properties at sub-lamellar levels. Presently, no experimental methods exist to conduct parametric studies elucidating the ultrastructural origins of bone tissue fragility. The introduction of this in-silico model presents an invaluable tool to bridge this knowledge gap in the future.
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Affiliation(s)
- Pengwei Xiao
- Department of Mechanical Engineering, University of Texas at San Antonio, USA
| | - Anuradha Roy
- Department of Management Science and Statistics, University of Texas at San Antonio, USA
| | - Xiaodu Wang
- Department of Mechanical Engineering, University of Texas at San Antonio, USA.
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Asaduzzaman Chowdhury M, Helal Hossain MD, Hossain N, Hossen Z, Arefin Kowser M, Masud Rana M. Advances in coatings on Mg alloys and their anti-microbial activity for implant applications. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.104214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Liu Z, Yamada S, Otsuka Y, Peñaflor Galindo TG, Tagaya M. Surface modification of hydroxyapatite nanoparticles for bone regeneration by controlling their surface hydration and protein adsorption states. Dalton Trans 2022; 51:9572-9583. [PMID: 35699123 DOI: 10.1039/d2dt00969b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Autogenous bone and metallic implant grafting has been used to repair and regenerate bone defects. However, there are still many unresolved problems. It is suggested that bioceramic nanoparticles should be developed and designed to promote effective bone regeneration. In addition, it is necessary to synthesize bioceramic nanoparticles that can support proteins related to bone repair and regeneration such as collagen and albumin. As the protein-interactive bioceramic, hydroxyapatite (HA) deserves to be mentioned and has several attractive properties that are useful in biomedical fields (e.g., biocompatibility, protein adsorption capacity and stability in the physiological environment). In order to prepare novel HA nanoparticles with high biocompatibility, it can be considered that human bones are mainly composed of HA and contain a small amount of silicate, and therefore, the design of coexistence of HA with silicate can be focused. Moreover, it is proposed that the state of the hydration layer on the nanoparticle surfaces can be controlled by introducing heteroelements and polymer chains, which have a great influence on the subsequent protein adsorption and cell adhesion. In this perspective, in order to develop novel bioceramic nanoparticles for the treatment of bone defect, the design of highly biocompatible HA nanoparticles and the control of the hydration layer and protein adsorption states on the surfaces were systematically discussed based on their surface modification techniques, which are very important for the proper understanding of the interface between cells and bioceramics, leading to the further application in biomedical fields.
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Affiliation(s)
- Zizhen Liu
- Department of Materials Science and Technology, Graduate School of Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
| | - Shota Yamada
- Department of Materials Science and Technology, Graduate School of Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
| | - Yuichi Otsuka
- Department of System Safety, Graduate School of Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Tania Guadalupe Peñaflor Galindo
- Department of General Education, National Institute of Technology, Nagaoka College, 888 Nishikatakai, Nagaoka, Niigata 940-8532, Japan
| | - Motohiro Tagaya
- Department of Materials Science and Technology, Graduate School of Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
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Kelly CN, Wang T, Crowley J, Wills D, Pelletier MH, Westrick ER, Adams SB, Gall K, Walsh WR. High-strength, porous additively manufactured implants with optimized mechanical osseointegration. Biomaterials 2021; 279:121206. [PMID: 34715639 DOI: 10.1016/j.biomaterials.2021.121206] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 10/04/2021] [Accepted: 10/20/2021] [Indexed: 01/12/2023]
Abstract
Optimization of porous titanium alloy scaffolds designed for orthopedic implants requires balancing mechanical properties and osseointegrative performance. The tradeoff between scaffold porosity and the stiffness/strength must be optimized towards the goal to improve long term load sharing while simultaneously promoting osseointegration. Osseointegration into porous titanium implants covering a wide range of porosity (0%-90%) and manufactured by laser powder bed fusion (LPBF) was evaluated with an established ovine cortical and cancellous defect model. Direct apposition and remodeling of woven bone was observed at the implant surface, as well as bone formation within the interstices of the pores. A linear relationship was observed between the porosity and benchtop mechanical properties of the scaffolds, while a non-linear relationship was observed between porosity and the ex vivo cortical bone-implant interfacial shear strength. Our study supports the hypothesis of porosity dependent performance tradeoffs, and establishes generalized relationships between porosity and performance for design of topological optimized implants for osseointegration. These results are widely applicable for orthopedic implant design for arthroplasty components, arthrodesis devices such as spinal interbody fusion implants, and patient matched implants for treatment of large bone defects.
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Affiliation(s)
- Cambre N Kelly
- Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Tian Wang
- Surgical and Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School UNSW Sydney, Kensington, Australia
| | - James Crowley
- Surgical and Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School UNSW Sydney, Kensington, Australia
| | - Dan Wills
- Surgical and Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School UNSW Sydney, Kensington, Australia
| | - Matthew H Pelletier
- Surgical and Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School UNSW Sydney, Kensington, Australia
| | | | - Samuel B Adams
- Department of Orthopedic Surgery, Duke University Medical Center, Durham, NC, USA
| | - Ken Gall
- Pratt School of Engineering, Duke University, Durham, NC, USA
| | - William R Walsh
- Surgical and Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School UNSW Sydney, Kensington, Australia.
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Pang S, Schwarcz HP, Jasiuk I. Interfacial bonding between mineral platelets in bone and its effect on mechanical properties of bone. J Mech Behav Biomed Mater 2020; 113:104132. [PMID: 33049620 DOI: 10.1016/j.jmbbm.2020.104132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/09/2020] [Accepted: 10/04/2020] [Indexed: 12/17/2022]
Abstract
Bone is a composite material consisting principally of apatite mineral, collagen fibrils, non-collagenous proteins, and other organic species. Recent electron microscopy studies have shown that the mineral in bone occurs as stacks of thin polycrystalline sheets ("mineral lamellae," MLs) which surround and lie between the collagen fibrils. We focus on the effect of the interface between these mineral lamellae on the mechanical properties of bone. Previous studies on bone treated with sodium hypochlorite (NaClO) to remove all organic material showed a greatly weakened mineral framework. Here, we treated femoral cortical bone with ethylenediamine (EDA), which only removes collagen, to study the effect of its removal on bone properties. We tested the degree of completion of the treatment by Raman spectroscopy and thermogravimetric analysis. When only collagen is removed, a continuous mineral structure remains and is less weakened than by NaClO treatment. Transmission electron microscopy study of finely ground particles of the EDA treated bone shows that stacks of MLs remain joined, whereas in NaClO treated bone, only isolated crystals are present. Thus, we infer that the MLs in bone are held together in stacks by an organic glue, which is destroyed by NaClO, but which survives the EDA treatment. We show that this glue may contribute to the stiffness, strength, and energy absorption of bone. Further studies are needed to discover the chemical nature of this glue. This study provides a starting point for such investigations.
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Affiliation(s)
- Siyuan Pang
- Department of Mechanical Science and Engineering, University of Illinois at Urbana Champaign, 1206 West Green Street, Urbana, IL, 61801, USA
| | - Henry P Schwarcz
- School of Earth, Environment and Society, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada.
| | - Iwona Jasiuk
- Department of Mechanical Science and Engineering, University of Illinois at Urbana Champaign, 1206 West Green Street, Urbana, IL, 61801, USA.
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Yamada S, Motozuka S, Tagaya M. Synthesis of nanostructured silica/hydroxyapatite hybrid particles containing amphiphilic triblock copolymer for effectively controlling hydration layer structures with cytocompatibility. J Mater Chem B 2020; 8:1524-1537. [PMID: 32003398 DOI: 10.1039/c9tb02534k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We synthesized nanostructured mesoporous silica (MS)/hydroxyapatite (HA) hybrid particles in the presence of amphiphilic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO20PPO70PEO20) triblock copolymer (P123). The particles exhibited slit-shaped mesostructures and underwent hybridization reaction between the MS and HA phases containing P123. Furthermore, the aggregated form of the particles exhibited dispersion stability in water in the monodispersed state (average particle size: 145 nm and coefficient of variation: 4.3% in the case of the maximum added amount of P123). Then, the structures of the hydration layer and the adsorbed protein on the particles were investigated to understand the effect of the hydration layer structures on the protein secondary structures. The ratio of the bonding water (intermediate and nonfreezing water) to free water increased upon hybridization, and it decreased with increasing P123 concentration. Upon hybridization, the component ratio of the asymmetric O-H stretching vibration between free water molecules decreased, and that of the symmetric O-H stretching vibration of intermediate water molecules increased. With increasing P123 concentration, the asymmetric O-H stretching vibration between free water molecules increased and the symmetric O-H stretching vibration of intermediate water molecules decreased. It was found that the protein native state component ratios of α-helix and β-sheet increased with increasing symmetric O-H stretching vibration between intermediate water molecules, and they decreased with decreasing asymmetric O-H stretching vibration between free water molecules. Moreover, the cytotoxicity against osteoblasts (MC3T3-E1) was evaluated and the hybrid particles exhibited a high cell density, indicating their bioactivity. On the hybrid particles interacting with P123, the cells were three-dimensionally assembled and uniaxially grown with the culture. Therefore, this is the first successful report of the synthesis of nanostructured MS/HA hybrid particles interacting with P123, and the controlled hydration layer structures on the particle surfaces were found to contribute to the protein secondary structures, promoting cytocompatibility.
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Affiliation(s)
- Shota Yamada
- Department of Materials Science and Technology, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata 940-2188, Japan.
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Meenashisundaram GK, Wang N, Maskomani S, Lu S, Anantharajan SK, Dheen ST, Nai SML, Fuh JYH, Wei J. Fabrication of Ti + Mg composites by three-dimensional printing of porous Ti and subsequent pressureless infiltration of biodegradable Mg. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 108:110478. [PMID: 31923949 DOI: 10.1016/j.msec.2019.110478] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 12/01/2022]
Abstract
A semi-degradable Ti + Mg composite with superior compression and cytotoxicity properties have been successfully fabricated using ink jet 3D printing followed by capillary mediated pressureless infiltration technique targeting orthopaedic implant applications. The composite exhibited low modulus (~5.2 GPa) and high ultimate compressive strength (~418 MPa) properties matching that of the human cortical bone. Ti + Mg composites with stronger 3D interconnected open-porous Ti networks are possible to be fabricated via 3D printing. Corrosion rate of samples measured through immersion testing using 0.9%NaCl solution at 37 °C indicate almost negligible corrosion rate for porous Ti (~1.14 μm/year) and <1 mm/year for Ti + Mg composites for 5 days of immersion, respectively. The composite significantly increased the SAOS-2 osteoblastic bone cell proliferation rate when compared to the 3D printed porous Ti samples and the increase is attributed to the exogenous Mg2+ ions originating from the Ti + Mg samples. The cell viability results indicated absent to mild cytotoxicity. An attempt is made to discuss the key considerations for net-shape fabrication of Ti + Mg implants using ink jet 3D printing followed by infiltration approach.
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Affiliation(s)
- Ganesh Kumar Meenashisundaram
- 3D Additive Manufacturing, Forming Technology group, Singapore Institute of Manufacturing and Technology, 73 Nanyang Drive, Singapore 637662, Singapore
| | - Niyou Wang
- Department of Mechanical Engineering, 9 Engineering drive 1, #07-08 Block EA, National University of Singapore, Singapore 117575, Singapore
| | - Silambarasan Maskomani
- Department of Anatomy, 4 Medical Drive, MD10, YLLSoM, National University of Singapore, 117594, Singapore
| | - Shenglu Lu
- 3D Additive Manufacturing, Forming Technology group, Singapore Institute of Manufacturing and Technology, 73 Nanyang Drive, Singapore 637662, Singapore
| | - Senthil Kumar Anantharajan
- Department of Mechanical Engineering, 9 Engineering drive 1, #07-08 Block EA, National University of Singapore, Singapore 117575, Singapore.
| | - Shaikali Thameem Dheen
- Department of Anatomy, 4 Medical Drive, MD10, YLLSoM, National University of Singapore, 117594, Singapore
| | - Sharon Mui Ling Nai
- 3D Additive Manufacturing, Forming Technology group, Singapore Institute of Manufacturing and Technology, 73 Nanyang Drive, Singapore 637662, Singapore
| | - Jerry Ying Hsi Fuh
- Department of Mechanical Engineering, 9 Engineering drive 1, #07-08 Block EA, National University of Singapore, Singapore 117575, Singapore
| | - Jun Wei
- 3D Additive Manufacturing, Forming Technology group, Singapore Institute of Manufacturing and Technology, 73 Nanyang Drive, Singapore 637662, Singapore.
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9
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Surface Modifications of the PMMA Optic of a Keratoprosthesis to Improve Biointegration. Cornea 2018; 36 Suppl 1:S15-S25. [PMID: 28968294 DOI: 10.1097/ico.0000000000001352] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Biointegration of a keratoprosthesis (KPro) is critical for the mitigation of various long-term postoperative complications. Biointegration of a KPro occurs between the haptic skirt (corneal graft) and the central optic [poly(methyl methacrylate) (PMMA)]. Various studies have highlighted common problems associated with poor bonding and biointegration between these 2 incompatible biomaterials. Resolution of these issues could be achieved by surface modification of the inert material (PMMA). A calcium phosphate (CaP) coating deposited on dopamine-activated PMMA sheets by simulated body fluid incubation (d-CaP coating) was shown to improve adhesion to collagen type I (main component of corneal stroma) compared with untreated PMMA and PMMA with other surface modifications. However, the d-CaP coating could easily undergo delamination, thereby reducing its potential for modification of KPro optical cylinders. In addition, the coating did not resemble the Ca and P composition of hydroxyapatite (HAp). A novel dip-coating method that involves the creation of cavities to trap and immobilize HAp nanoparticles on the PMMA surface was introduced to address the problems associated with the d-CaP coating. The newly obtained coating offered high hydrophilicity, resistance to delamination, and preservation of the Ca and P composition of HAp. These advantages resulted in improved adhesion strength by more than 1 order of magnitude compared with untreated PMMA. With respect to biointegration, human corneal stromal fibroblasts were able to adhere strongly and proliferate on HAp-coated PMMA. Furthermore, the new coating technique could be extended to immobilization of HAp nanoparticles on 3-mm-diameter PMMA cylinders, bringing it closer to clinical application.
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Riau AK, Mondal D, Yam GHF, Setiawan M, Liedberg B, Venkatraman SS, Mehta JS. Surface Modification of PMMA to Improve Adhesion to Corneal Substitutes in a Synthetic Core-Skirt Keratoprosthesis. ACS APPLIED MATERIALS & INTERFACES 2015; 7:21690-21702. [PMID: 26389670 DOI: 10.1021/acsami.5b07621] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Patients with advanced corneal disease do poorly with conventional corneal transplantation and require a keratoprosthesis (KPro) for visual rehabilitation. The most widely used KPro is constructed using poly(methyl methacrylate) (PMMA) in the central optical core and a donor cornea as skirt material. In many cases, poor adherence between the PMMA and the soft corneal tissue is responsible for device "extrusion" and bacterial infiltration. The interfacial adhesion between the tissue and the PMMA was therefore critical to successful implantation and device longevity. In our approach, we modified the PMMA surface using oxygen plasma (plasma group); plasma followed by calcium phosphate (CaP) coating (p-CaP); dopamine followed by CaP coating (d-CaP); or plasma followed by coating with (3-aminopropyl)triethoxysilane (3-APTES). To create a synthetic KPro model, we constructed and attached 500 μm thick collagen type I hydrogel on the modified PMMA surfaces. Surface modifications produced significantly improved interfacial adhesion strength compared to untreated PMMA (p < 0.001). The p-CaP group yielded the best interfacial adhesion with the hydrogel (177 ± 27 mN/cm(2)) followed by d-CaP (168 ± 31 mN/cm(2)), 3-APTES (145 ± 12 mN/cm(2)), and plasma (119 ± 10 mN/cm(2)). Longer-term stability of the adhesion was achieved by d-CaP, which, after 14 and 28 days of incubation in phosphate buffered saline, yielded 164 ± 25 mN/cm(2) (p = 0.906 compared to adhesion at day 1) and 131 ± 20 mN/cm(2) (p = 0.053), respectively. In contrast, significant reduction of adhesion strength was observed in p-CaP group over time (p < 0.001). All surface coatings were biocompatible to human corneal stromal fibroblasts, except for the 3-APTES group, which showed no live cells at 72 h of culture. In contrast, cells on d-CaP surface showed good anchorage, evidenced by the expression of focal adhesion complex (paxillin and vinculin), and prominent filopodia protrusions. In conclusion, d-CaP can not only enhance and provide stability to the adhesion of collagen hydrogel on the PMMA surface but also promote biointegration.
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Affiliation(s)
- Andri K Riau
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798, Singapore
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute , Singapore 169856, Singapore
| | - Debasish Mondal
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute , Singapore 169856, Singapore
| | - Gary H F Yam
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute , Singapore 169856, Singapore
| | - Melina Setiawan
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute , Singapore 169856, Singapore
| | - Bo Liedberg
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798, Singapore
- Center for Biomimetic Sensor Science, Nanyang Technological University , Singapore 637553, Singapore
| | - Subbu S Venkatraman
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798, Singapore
| | - Jodhbir S Mehta
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798, Singapore
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute , Singapore 169856, Singapore
- Singapore National Eye Center , Singapore 168751, Singapore
- Department of Clinical Sciences, Duke-NUS Graduate Medical School , Singapore 169857, Singapore
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11
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Abstract
The interface between collagen and the mineral reinforcement phase, carbonated hydroxyapatite (cAp), is essential for bone's remarkable functionality as a biological composite material. The very small dimensions of the cAp phase and the disparate natures of the reinforcement and matrix are essential to the material's performance but also complicate study of this interface. This article summarizes what is known about the cAp-collagen interface in bone and begins with descriptions of the matrix and reinforcement roles in composites, of the phases bounding the interface, of growth of cAp growing within the collagen matrix, and of the effect of intra- and extrafibrilar mineral on determinations of interfacial properties. Different observed interfacial interactions with cAp (collagen, water, non-collagenous proteins) are reviewed; experimental results on interface interactions during loading are reported as are their influence on macroscopic mechanical properties; conclusions of numerical modeling of interfacial interactions are also presented. The data suggest interfacial interlocking (bending of collagen molecules around cAp nanoplatelets) and water-mediated bonding between collagen and cAp are essential to load transfer. The review concludes with descriptions of areas where new research is needed to improve understanding of how the interface functions.
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Affiliation(s)
- S R Stock
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611-3008, USA,
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12
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Cellet TSP, Pereira GM, Muniz EC, Silva R, Rubira AF. Hydroxyapatite nanowhiskers embedded in chondroitin sulfate microspheres as colon targeted drug delivery systems. J Mater Chem B 2015; 3:6837-6846. [DOI: 10.1039/c5tb00856e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An inorganic/organic hybrid material with a triggering mechanism for specific drug delivery at the colon is synthesized.
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Affiliation(s)
- T. S. P. Cellet
- Departamento de Química
- Universidade Estadual de Maringá
- CEP: 87020-900 – Maringá
- Brazil
| | - G. M. Pereira
- Departamento de Química
- Universidade Estadual de Maringá
- CEP: 87020-900 – Maringá
- Brazil
| | - E. C. Muniz
- Departamento de Química
- Universidade Estadual de Maringá
- CEP: 87020-900 – Maringá
- Brazil
| | - R. Silva
- Departamento de Química
- Universidade Estadual de Maringá
- CEP: 87020-900 – Maringá
- Brazil
| | - A. F. Rubira
- Departamento de Química
- Universidade Estadual de Maringá
- CEP: 87020-900 – Maringá
- Brazil
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14
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Barkaoui A, Hambli R, Tavares JMR. Effect of material and structural factors on fracture behaviour of mineralised collagen microfibril using finite element simulation. Comput Methods Biomech Biomed Engin 2014; 18:1181-1190. [DOI: 10.1080/10255842.2014.883601] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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15
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Luo Q, Leng H, Wang X, Zhou Y, Rong Q. The role of water and mineral-collagen interfacial bonding on microdamage progression in bone. J Orthop Res 2014; 32:217-23. [PMID: 24122969 DOI: 10.1002/jor.22501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 09/17/2013] [Indexed: 02/04/2023]
Abstract
Microdamage would be accumulated in bone due to high-intensity training or even normal daily activity, which may consequently cause fragility fracture or stress fracture. On the other hand, microdamage formation serves as a toughening mechanism in bone. However, the mechanisms that control microdamage initiation and accumulation in bone are still poorly understood. Our previous finite element model indicated that different interfacial properties between mineral and collagen in bone may lead to distinct patterns of microdamage accumulation. Therefore, the current study was designed to examine such prediction and to investigate the role of water and mineral-collagen interactions on microdamage accumulation in bone. To address these issues, 48 mice femurs were divided randomly into four groups. These groups were dehydrated or treated with perfluorotripropylamine (PFTA) or NaF solution to change water distribution and mineral-collagen interfacial bonding in bone. After three-point bending fatigue tests, the types of microdamage (i.e., linear microcracks or diffuse damage) formed in bone were compared between different groups. The results suggested that (1) bone tissues with strong mineral-collagen interfacial bonding facilitate the formation of linear microcraks, and (2) water has little contribution to the growth of microcracks.
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Affiliation(s)
- Qing Luo
- College of Engineering, Peking University, Beijing, 100871, China; Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, 100081, China
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Zakaria SM, Sharif Zein SH, Othman MR, Yang F, Jansen JA. Nanophase Hydroxyapatite as a Biomaterial in Advanced Hard Tissue Engineering: A Review. TISSUE ENGINEERING PART B-REVIEWS 2013; 19:431-41. [DOI: 10.1089/ten.teb.2012.0624] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Siti Maisurah Zakaria
- School of Chemical Engineering, Engineering Campus, University Sains Malaysia, Nibong Tebal, Malaysia
| | | | - Mohd. Roslee Othman
- School of Chemical Engineering, Engineering Campus, University Sains Malaysia, Nibong Tebal, Malaysia
| | - Fang Yang
- Department of Biomaterials, College of Dental Science, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - John A. Jansen
- Department of Biomaterials, College of Dental Science, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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17
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Deymier-Black AC, Singhal A, Yuan F, Almer JD, Brinson LC, Dunand DC. Effect of high-energy X-ray irradiation on creep mechanisms in bone and dentin. J Mech Behav Biomed Mater 2013; 21:17-31. [DOI: 10.1016/j.jmbbm.2013.01.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/08/2013] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
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18
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Effect of stress and temperature on the micromechanics of creep in highly irradiated bone and dentin. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2013; 33:1467-75. [DOI: 10.1016/j.msec.2012.12.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/12/2012] [Accepted: 12/14/2012] [Indexed: 11/20/2022]
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19
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Zorn K, Mitró D, Vorndran E, Gbureck U, Müller FA. Hydrothermal synthesis of calcium-deficient hydroxyapatite whiskers and their thermal transformation to polycrystalline β-tricalcium phosphate short fibers. BIOINSPIRED BIOMIMETIC AND NANOBIOMATERIALS 2013. [DOI: 10.1680/bbn.12.00019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Resorbable calcium phosphate fibers are of particular interest to reinforce biodegradable bone substitutes for load-bearing applications. The aim of the present study was to prepare calcium-deficient hydroxyapatite (dHAp) whiskers with a molar Ca/P ratio of 1·5 by a hydrothermal synthesis and to transform them to β-tricalcium phosphate (β-TCP) by a subsequent thermal treatment. For the hydrothermal synthesis, calcium tripolyphosphate was used and different amounts of 2-propanol were added to adjust the pH. Average whisker lengths of 160 µm were obtained at a 2-propanol content of 27 volume-percent. However, 33% dicalcium phosphate anhydrate (DCPA) were present as a secondary phase. The amount of DCPA could be reduced by increasing the amount of 2-propanol. Whisker samples consisting of 88% dHAp and 12% DCPA were selected to investigate microstructural changes and phase transformations during thermal treatment. Polycrystalline single phase -TCP short fibers were obtained after a thermal treatment at 1125°C.
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Affiliation(s)
- Katharina Zorn
- Institute of Materials Science and Technology (IMT), Friedrich-Schiller-University of Jena, Jena, Germany
| | - Daniel Mitró
- Institute of Materials Science and Technology (IMT), Friedrich-Schiller-University of Jena, Jena, Germany
| | - Elke Vorndran
- Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Würzburg, Germany
| | - Uwe Gbureck
- Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Würzburg, Germany
| | - Frank A. Müller
- Institute of Materials Science and Technology (IMT), Friedrich-Schiller-University of Jena, Jena, Germany
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20
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Barkaoui A, Hambli R. Nanomechanical properties of mineralised collagen microfibrils based on finite elements method: biomechanical role of cross-links. Comput Methods Biomech Biomed Engin 2013; 17:1590-601. [PMID: 23439084 DOI: 10.1080/10255842.2012.758255] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hierarchical structures in bio-composites such as bone tissue have many scales or levels and synergic interactions between the different levels. They also have a highly complex architecture in order to fulfil their biological and mechanical functions. In this study, a new three-dimensional (3D) model based on the finite elements (FEs) method was used to model the relationship between the hierarchical structure and the properties of the constituents at the sub-structure scale (mineralised collagen microfibrils) and to investigate their apparent nanomechanical properties. The results of the proposed FE simulations show that the elastic properties of microfibrils depend on different factors such as the number of cross-links, the mechanical properties and the volume fraction of phases. The results obtained under compression loading at a small deformation < 2% show that the microfibrils have a Young's modulus (Ef) ranging from 0.4 to 1.16 GPa and a Poisson's ratio ranging from 0.26 to 0.3. These results are in excellent agreement with experimental data (X-ray, AFM and MEMS) and molecular simulations.
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Affiliation(s)
- Abdelwahed Barkaoui
- a PRISME Laboratory, EA4229, University of Orleans , Polytech' Orléans, 8, Rue Léonard de Vinci 45072, Orléans , France
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21
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Russell NA, Pelletier MH, Bruce WJ, Walsh WR. The effect of gamma irradiation on the anisotropy of bovine cortical bone. Med Eng Phys 2012; 34:1117-22. [DOI: 10.1016/j.medengphy.2011.11.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/22/2011] [Accepted: 11/29/2011] [Indexed: 02/02/2023]
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22
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Choi Y, Cho SY, Park DJ, Park HH, Heo S, Jin HJ. Silk fibroin particles as templates for mineralization of calcium-deficient hydroxyapatite. J Biomed Mater Res B Appl Biomater 2012; 100:2029-34. [DOI: 10.1002/jbm.b.32766] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 06/05/2012] [Accepted: 06/07/2012] [Indexed: 11/12/2022]
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23
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Singhal A, Almer J, Dunand D. Variability in the nanoscale deformation of hydroxyapatite during compressive loading in bovine bone. Acta Biomater 2012; 8:2747-58. [PMID: 22465576 DOI: 10.1016/j.actbio.2012.03.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/10/2012] [Accepted: 03/21/2012] [Indexed: 11/27/2022]
Abstract
High-energy synchrotron X-ray diffraction is used to study in situ elastic strains in hydroxyapatite (HAP) for bovine femur cortical bone subjected to uniaxial compressive loading. Load-unload tests at room temperature (27°C) and body temperature (37°C) show that the load transfer to the stiff nanosized HAP platelets from the surrounding compliant protein matrix does not vary significantly (p<0.05) with temperature. This emphasizes that the stiffness of bone is controlled by the stiffness of the HAP phase, which remains unaffected by this change in temperature. Both the extent of hysteresis and the residual value of internal strains developed in HAP during load-unload cycling from 0 to -100 MPa increase significantly (p<0.05) with the number of loading cycles, indicative of strain energy dissipation and accumulation of permanent deformation. Monotonic loading tests, conducted at body temperature to determine the spatial variation of properties within the femur, illustrate that the HAP phase carries lower strain (and thus stresses) at the anterio-medial aspect of the femur than at the anterio-lateral aspect. This is correlated to higher HAP volume fractions in the former location (p<0.05). The Young's modulus of the bone is also found to correlate with the HAP volume fraction and porosity (p<0.05). Finally, samples with a primarily plexiform microstructure are found to be stiffer than those with a primarily Haversian microstructure (p<0.05).
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24
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Evolution of load transfer between hydroxyapatite and collagen during creep deformation of bone. Acta Biomater 2012; 8:253-61. [PMID: 21878399 DOI: 10.1016/j.actbio.2011.08.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 08/10/2011] [Accepted: 08/15/2011] [Indexed: 11/20/2022]
Abstract
While the matrix/reinforcement load-transfer occurring at the micro- and nanoscale in nonbiological composites subjected to creep deformation is well understood, this topic has been little studied in biological composites such as bone. Here, for the first time in bone, the mechanisms of time-dependent load transfer occurring at the nanoscale between the collagen phase and the hydroxyapatite (HAP) platelets are studied. Bovine cortical bone samples are subjected to synchrotron X-ray diffraction to measure in situ the evolution of elastic strains in the crystalline HAP phase and the evolution of viscoelastic strains accumulating in the mineralized collagen fibrils under creep conditions at body temperature. For a constant compressive stress, both types of strains increase linearly with time. This suggests that bone, as it deforms macroscopically, is behaving as a traditional composite, shedding load from the more compliant, viscoelastic collagen matrix to the reinforcing elastic HAP platelets. This behavior is modeled by finite-element simulation carried out at the fibrillar level.
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25
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Singhal A, Deymier-Black AC, Almer J, Dunand D. Effect of high-energy X-ray doses on bone elastic properties and residual strains. J Mech Behav Biomed Mater 2011; 4:1774-86. [DOI: 10.1016/j.jmbbm.2011.05.035] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 05/17/2011] [Accepted: 05/28/2011] [Indexed: 11/29/2022]
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26
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Feng L, Jasiuk I. Multi-scale characterization of swine femoral cortical bone. J Biomech 2011; 44:313-20. [DOI: 10.1016/j.jbiomech.2010.10.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 10/12/2010] [Indexed: 10/18/2022]
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27
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Dong XN, Zoghi M, Ran Q, Wang X. Collagen mutation causes changes of the microdamage morphology in bone of an OI mouse model. Bone 2010; 47:1071-5. [PMID: 20736092 PMCID: PMC2970676 DOI: 10.1016/j.bone.2010.08.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 08/14/2010] [Accepted: 08/16/2010] [Indexed: 11/26/2022]
Abstract
Previous studies have postulated that ultrastructural changes may alter the pattern and capacity of microdamage accumulation in bone. Using an osteogenesis imperfecta (OI) mouse model, this study was performed to investigate the correlation of collagen mutation with the microdamage morphology and the associated brittleness of bone. In this study, femurs from mild OI and wild type mice were fatigued under four-point bending to create microdamage in the specimens. Then, the microdamage morphology of these specimens was examined using the bulk-staining technique with basic fuchsin. Similar with the results of previous studies, it was observed that linear microcracks were formed more easily in compression, whereas diffuse damage was induced more readily in tension for both wild-type and mild-type mice. However, less diffuse damage was found in the tensile side of mild OI mouse femurs (collagen mutation) compared with those of wild type mice, showing that the microdamage morphology is correlated to the brittleness of bone. The results of this study provide direct evidence that supports the prediction made by the previous numerical simulation studies, suggesting that microdamage morphology in bone is significantly correlated with the integrity of the collagen phase.
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Affiliation(s)
- X Neil Dong
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
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28
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Thurner PJ, Chen CG, Ionova-Martin S, Sun L, Harman A, Porter A, Ager JW, Ritchie RO, Alliston T. Osteopontin deficiency increases bone fragility but preserves bone mass. Bone 2010; 46:1564-73. [PMID: 20171304 PMCID: PMC2875278 DOI: 10.1016/j.bone.2010.02.014] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 12/17/2022]
Abstract
The ability of bone to resist catastrophic failure is critically dependent upon the material properties of bone matrix, a composite of hydroxyapatite, collagen type I, and noncollagenous proteins. These properties include elastic modulus, hardness, and fracture toughness. Like other aspects of bone quality, matrix material properties are biologically-defined and can be disrupted in skeletal disease. While mineral and collagen have been investigated in greater detail, the contribution of noncollagenous proteins such as osteopontin to bone matrix material properties remains unclear. Several roles have been ascribed to osteopontin in bone, many of which have the potential to impact material properties. To elucidate the role of osteopontin in bone quality, we evaluated the structure, composition, and material properties of bone from osteopontin-deficient mice and wild-type littermates at several length scales. Most importantly, the results show that osteopontin deficiency causes a 30% decrease in fracture toughness, suggesting an important role for OPN in preventing crack propagation. This significant decline in fracture toughness is independent of changes in whole bone mass, structure, or matrix porosity. Using nanoindentation and quantitative backscattered electron imaging to evaluate osteopontin-deficient bone matrix at the micrometer level, we observed a significant reduction in elastic modulus and increased variability in calcium concentration. Matrix heterogeneity was also apparent at the ultrastructural level. In conclusion, we find that osteopontin is essential for the fracture toughness of bone, and reduced toughness in osteopontin-deficient bone may be related to the increased matrix heterogeneity observed at the micro-scale. By exploring the effects of osteopontin deficiency on bone matrix material properties, composition and organization, this study suggests that reduced fracture toughness is one mechanism by which loss of noncollagenous proteins contribute to bone fragility.
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Affiliation(s)
- Philipp J. Thurner
- Department of Orthopaedic Surgery, University of California San Francisco, CA, USA
- School of Engineering Sciences, University of Southampton, UK
| | - Carol G. Chen
- Department of Orthopaedic Surgery, University of California San Francisco, CA, USA
| | - Sophi Ionova-Martin
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Luling Sun
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | | | | | - Joel W. Ager
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Robert O. Ritchie
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, Department of Otolaryngology, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California San Francisco, CA, USA
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29
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Chang HJ, Wu CM, Chang YC, Fanchiang JC, Shieh DB, Wong TY. Collagen enhances compatibility and strength of glass ionomers. J Dent Res 2009; 88:449-54. [PMID: 19493889 DOI: 10.1177/0022034509337478] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Glass ionomers have been used for perforation repair and retrograde filling where biointegration with periodontal tissue is required. Collagen has been demonstrated to promote cellular adhesion and enhance mineral tissue compressive strength. It was hypothesized that an appropriate concentration of collagen integrated into glass ionomer may improve both bio-compatibility and the mechanical properties of the material. By SEM and AFM, we discovered 70-nm granules appearing on the surfaces of glass-ionomer/collagen hybrids. Acid-etching revealed irregularly shaped particles interlinked by membrane-like sheets on the surface of the material with the typical 70-nm granules. WST-1 assay showed that acid-etching significantly enhanced the viability of attached gingival fibroblasts. However, the glass-ionomer/collagen hybrids' combined surface-etching outperformed other groups. The glass-ionomer/collagen hybrids presented enhanced compressive strength when integrated with 0.01% collagen, while higher concentrations of collagen compromised their mechanical property. In summary, collagen improved both the mechanical and biocompatible properties of glass ionomers. Further in vivo study is warranted.
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Affiliation(s)
- H-J Chang
- Department of Dentistry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, 81346
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30
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Wynnyckyj C, Omelon S, Savage K, Damani M, Chachra D, Grynpas MD. A new tool to assess the mechanical properties of bone due to collagen degradation. Bone 2009; 44:840-8. [PMID: 19150659 DOI: 10.1016/j.bone.2008.12.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 09/30/2008] [Accepted: 12/09/2008] [Indexed: 10/21/2022]
Abstract
Current clinical tools for evaluating fracture risk focus only on the mineral phase of bone. However, changes in the collagen matrix may affect bone mechanical properties, increasing fracture risk while remaining undetected by conventional screening methods such as dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS). The mechanical response tissue analyzer (MRTA) is a non-invasive, radiation-free potential clinical tool for evaluating fracture risk. The objectives of this study were two-fold: to investigate the ability of the MRTA to detect changes in mechanical properties of bone as a result of treatment with 1 M potassium hydroxide (KOH) and to evaluate the differences between male and female bone in an emu model. DXA, QUS, MRTA and three-point bending measurements were performed on ex vivo emu tibiae before and after KOH treatment. Male and female emu tibiae were endocortically treated with 1 M KOH solution for 1-14 days, resulting in negligible collagen loss (0.05%; by hydroxyproline assay) and overall mass loss (0.5%). Three-point bending and MRTA detected significant changes in modulus between days 1 and 14 of KOH treatment (-18%) while all values measured by DXA and QUS varied by less than 2%. This close correlation between MRTA and three-point bending results support the utility of the MRTA as a clinical tool to predict fracture risk. In addition, the significant reduction in modulus contrasted with the negligible amount of collagen removal from the bone after KOH exposure. As such, the significant changes in bone mechanical properties may be due to partial debonding between the mineral and organic matrix or in situ collagen degradation rather than collagen removal. In terms of sex differences, male emu tibiae had significantly decreased failure stress and increased failure strain and toughness compared to female tibiae with increasing KOH treatment time.
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Affiliation(s)
- C Wynnyckyj
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
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31
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Leng H, Dong XN, Wang X. Progressive post-yield behavior of human cortical bone in compression for middle-aged and elderly groups. J Biomech 2009; 42:491-7. [PMID: 19150716 DOI: 10.1016/j.jbiomech.2008.11.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Revised: 11/13/2008] [Accepted: 11/14/2008] [Indexed: 10/21/2022]
Abstract
In this study, a progressive loading regimen (load-dwell-unloading-dwell-reloading) was applied on bone samples to examine the compressive post-yield response of bone at increasing strain levels. Cortical bone specimens from human tibiae of two age groups (middle-aged group: 53+/-2 years, 4 females and 4 males, elderly group: 83+/-6 years, 4 females and 4 males) were loaded in compression using the progressive loading scheme. Modulus degradation, plastic deformation, viscous response, and energy dissipation of bone during post-yield deformation were assessed. Although initial modulus was not significantly different between the two age groups, the degradation of modulus with the applied strain in the elderly group was faster than in the middle-aged group. The modulus loss (or microdamage accumulation) of bone occurred prior to plastic deformation. Plastic strain had a similar linear relationship with the applied strain for both middle-aged and the elderly group although middle-aged bone yielded at a greater strain. The viscoelastic time constant changed similarly with increasing strain for the two groups, whereas a higher magnitude of stress relaxation was observed in the middle-aged group. Energy dissipation was investigated through three pathways: elastic release strain energy, hysteresis energy, and plastic strain energy. The middle-aged group had significantly greater capacity of energy dissipation than the elderly group in all three pathways. The information obtained may provide important insights in age-related effects on bone fragility.
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Affiliation(s)
- Huijie Leng
- Department of Orthopaedics, Peking University Third Hospital, Beijing 100191, China
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32
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Nyman JS, Leng H, Dong XN, Wang X. Differences in the mechanical behavior of cortical bone between compression and tension when subjected to progressive loading. J Mech Behav Biomed Mater 2008; 2:613-9. [PMID: 19716106 DOI: 10.1016/j.jmbbm.2008.11.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2008] [Revised: 09/26/2008] [Accepted: 11/23/2008] [Indexed: 10/21/2022]
Abstract
The hierarchical arrangement of collagen and mineral into bone tissue presumably maximizes fracture resistance with respect to the predominant strain mode in bone. Thus, the ability of cortical bone to dissipate energy may differ between compression and tension for the same anatomical site. To test this notion, we subjected bone specimens from the anterior quadrant of human cadaveric tibiae to a progressive loading scheme in either uniaxial tension or uniaxial compression. One tension (dog-bone shape) and one compression specimen (cylindrical shape) were collected each from tibiae of nine middle aged male donors. At each cycle of loading-dwell-unloading-dwell-reloading, we calculated maximum stress, permanent strain, modulus, stress relaxation, time constant, and three pathways of energy dissipation for both loading modes. In doing so, we found that bone dissipated greater energy through the mechanisms of permanent and viscoelastic deformation in compression than in tension. On the other hand, however, bone dissipated greater energy through the release of surface energy in tension than in compression. Moreover, differences in the plastic and viscoelastic properties after yielding were not reflected in the evolution of modulus loss (an indicator of damage accumulation), which was similar for both loading modes. A possible explanation is that differences in damage morphology between the two loading modes may favor the plastic and viscoelastic energy dissipation in compression, but facilitate the surface energy release in tension. Such detailed information about failure mechanisms of bone at the tissue-level would help explain the underlying causes of bone fractures.
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Affiliation(s)
- Jeffry S Nyman
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37215, United States
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33
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Dong XN, Guda T, Millwater HR, Wang X. Probabilistic failure analysis of bone using a finite element model of mineral-collagen composites. J Biomech 2008; 42:202-9. [PMID: 19058806 DOI: 10.1016/j.jbiomech.2008.10.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 09/05/2008] [Accepted: 10/20/2008] [Indexed: 11/19/2022]
Abstract
Microdamage accumulation is a major pathway for energy dissipation during the post-yield deformation of bone. In this study, a two-dimensional probabilistic finite element model of a mineral-collagen composite was developed to investigate the influence of the tissue and ultrastructural properties of bone on the evolution of microdamage from an initial defect in tension. The probabilistic failure analyses indicated that the microdamage progression would be along the plane of the initial defect when the debonding at mineral-collagen interfaces was either absent or limited in the vicinity of the defect. In this case, the formation of a linear microcrack would be facilitated. However, the microdamage progression would be scattered away from the initial defect plane if interfacial debonding takes place at a large scale. This would suggest the possible formation of diffuse damage. In addition to interfacial debonding, the sensitivity analyses indicated that the microdamage progression was also dependent on the other material and ultrastructural properties of bone. The intensity of stress concentration accompanied with microdamage progression was more sensitive to the elastic modulus of the mineral phase and the nonlinearity of the collagen phase, whereas the scattering of failure location was largely dependent on the mineral to collagen ratio and the nonlinearity of the collagen phase. The findings of this study may help understanding the post-yield behavior of bone at the ultrastructural level and shed light on the underlying mechanism of bone fractures.
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Affiliation(s)
- X Neil Dong
- Department of Mechanical Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
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34
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Mousny M, Omelon S, Wise L, Everett ET, Dumitriu M, Holmyard DP, Banse X, Devogelaer JP, Grynpas MD. Fluoride effects on bone formation and mineralization are influenced by genetics. Bone 2008; 43:1067-74. [PMID: 18755305 PMCID: PMC2664744 DOI: 10.1016/j.bone.2008.07.248] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 07/17/2008] [Accepted: 07/31/2008] [Indexed: 01/08/2023]
Abstract
INTRODUCTION A variation in bone response to fluoride (F(-)) exposure has been attributed to genetic factors. Increasing fluoride doses (0 ppm, 25 ppm, 50 ppm, 100 ppm) for three inbred mouse strains with different susceptibilities to developing dental enamel fluorosis (A/J, a "susceptible" strain; SWR/J, an "intermediate" strain; 129P3/J, a "resistant" strain) had different effects on their cortical and trabecular bone mechanical properties. In this paper, the structural and material properties of the bone were evaluated to explain the previously observed changes in mechanical properties. MATERIALS AND METHODS This study assessed the effect of increasing fluoride doses on the bone formation, microarchitecture, mineralization and microhardness of the A/J, SWR/J and 129P3/J mouse strains. Bone microarchitecture was quantified with microcomputed tomography and strut analysis. Bone formation was evaluated by static histomorphometry. Bone mineralization was quantified with backscattered electron (BSE) imaging and powder X-ray diffraction. Microhardness measurements were taken from the vertebral bodies (cortical and trabecular bones) and the cortex of the distal femur. RESULTS Fluoride treatment had no significant effect on bone microarchitecture for any of the strains. All three strains demonstrated a significant increase in osteoid formation at the largest fluoride dose. Vertebral body trabecular bone BSE imaging revealed significantly decreased mineralization heterogeneity in the SWR/J strain at 50 ppm and 100 ppm F(-). The trabecular and cortical bone mineralization profiles showed a non-significant shift towards higher mineralization with increasing F(-) dose in the three strains. Powder X-ray diffraction showed significantly smaller crystals for the 129P3/J strain, and increased crystal width with increasing F(-) dose for all strains. There was no effect of F(-) on trabecular and cortical bone microhardness. CONCLUSION Fluoride treatment had no significant effect on bone microarchitecture in these three strains. The increased osteoid formation and decreased mineralization heterogeneity support the theory that F(-) delays mineralization of new bone. The increasing crystal width with increasing F(-) dose confirms earlier results and correlates with most of the decreased mechanical properties. An increase in bone F(-) may affect the mineral-organic interfacial bonding and/or bone matrix proteins, interfering with bone crystal growth inhibition on the crystallite faces as well as bonding between the mineral and organic interface. The smaller bone crystallites of the 129P3/J (resistant) strain may indicate a stronger organic/inorganic interface, reducing crystallite growth rate and increasing interfacial mechanical strength.
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Affiliation(s)
- M Mousny
- Orthopaedic Research Laboratory, Cliniques Universitaires Saint-Luc, Catholic University of Louvain, Brussels, Belgium
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35
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Sasaki N, Nozoe T, Nishihara R, Fukui A. Effect of mineral dissolution from bone specimens on the viscoelastic properties of cortical bone. J Biomech 2008; 41:3511-4. [DOI: 10.1016/j.jbiomech.2008.09.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 09/04/2008] [Accepted: 09/05/2008] [Indexed: 10/21/2022]
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36
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Miller E, Delos D, Baldini T, Wright TM, Camacho NP. Abnormal mineral-matrix interactions are a significant contributor to fragility in oim/oim bone. Calcif Tissue Int 2007; 81:206-14. [PMID: 17660935 PMCID: PMC2945147 DOI: 10.1007/s00223-007-9045-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Accepted: 04/12/2007] [Indexed: 10/23/2022]
Abstract
The presence of abnormal type I collagen underlies the tissue fragility in the heritable disease osteogenesis imperfecta (OI), though the specific mechanism remains ill-defined. The current study addressed the question of how an abnormal collagen-based matrix contributes to reduced bone strength in OI by comparing the material properties of mineralized and demineralized bone from the oim/oim mouse, a model of OI that contains homotrimeric (alpha1(3)(I)) type I collagen, with the properties of bone from wildtype (+/+) mice. Femoral three-point bend tests combined with geometric analyses were conducted on intact (mineralized) 14-week-old oim/oim and +/+ mice. To investigate the bone matrix properties, tensile tests combined with geometric analyses were conducted on demineralized femora. The majority of the properties of the mineralized oim/oim bone were inferior to those of the +/+ bone, including greater brittleness (+78.6%) and lower toughness (-69.2%). In contrast, tensile measurements on the demineralized bone revealed no significant differences between the oim/oim and +/+ bone, indicating that the matrix itself was not brittle. These results support the concept that deficient material properties of the demineralized bone matrix itself are not the principal cause of the severe fragility in this model of OI. It is likely the abnormal collagen scaffold serves as a template for abnormal mineral deposition, resulting in an incompetent mineral-matrix interaction that contributes significantly to the inferior material properties of bone in oim/oim mice.
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Affiliation(s)
- Elizabeth Miller
- Musculoskeletal Integrity Program, Research Division, Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021, USA
| | - Demetris Delos
- Musculoskeletal Integrity Program, Research Division, Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021, USA
| | | | - Timothy M. Wright
- Musculoskeletal Integrity Program, Research Division, Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021, USA
| | - Nancy Pleshko Camacho
- Musculoskeletal Integrity Program, Research Division, Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021, USA
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37
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Sarvestani AS, He X, Jabbari E. Osteonectin-derived peptide increases the modulus of a bone-mimetic nanocomposite. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 37:229-34. [PMID: 17609937 DOI: 10.1007/s00249-007-0198-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 05/21/2007] [Accepted: 05/28/2007] [Indexed: 10/23/2022]
Abstract
Many factors contribute to the toughness of bone including the presence of nano-size apatite crystals, a dense network of collagen fibers, and acidic proteins with the ability to link the mineral phase to the gelatinous collagen phase. We investigated the effect of a glutamic acid (negatively charged) peptide (Glu6), which mimics the terminal region of the osteonectin glycoprotein of bone, on the shear modulus of a synthetic hydrogel/apatite nanocomposite. One end of the synthesized peptide was functionalized with an acrylate group (Ac-Glu6) to covalently attach the peptide to the hydrogel phase of the composite matrix. When microapatite crystals (5 microm diameter) were used, addition of Ac-Glu6 peptide did not affect the modulus of the microcomposite. However, when nanoapatite crystals (100 nm diameter) were used, addition of Ac-Glu6 resulted in significant reinforcement of the shear modulus of the nanocomposite ( approximately 100% in elastic shear modulus). Furthermore, addition of Ac-Gly6 (a neutral glycine sequence) or Ac-Lys6 (a positively charged sequence) did not reinforce the nanocomposite. These results demonstrate that the reinforcement effect of the Glu6 peptide, a sequence in the terminal region of osteonectin, is modulated by the size of the apatite crystals. The findings of this work can be used to develop advanced biomimetic composites for skeletal tissue regeneration.
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Affiliation(s)
- Alireza S Sarvestani
- Department of Chemical Engineering, Swearingen Engineering Center, University of South Carolina, Columbia, SC 29208, USA
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38
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Kindt JH, Thurner PJ, Lauer ME, Bosma BL, Schitter G, Fantner GE, Izumi M, Weaver JC, Morse DE, Hansma PK. In situ observation of fluoride-ion-induced hydroxyapatite-collagen detachment on bone fracture surfaces by atomic force microscopy. NANOTECHNOLOGY 2007; 18:135102. [PMID: 21730373 DOI: 10.1088/0957-4484/18/13/135102] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The topography of freshly fractured bovine and human bone surfaces was determined by the use of atomic force microscopy (AFM). Fracture surfaces from both kinds of samples exhibited complex landscapes formed by hydroxyapatite mineral platelets with lateral dimensions ranging from ∼90 nm × 60 nm to ∼20 nm × 20 nm. Novel AFM techniques were used to study these fracture surfaces during various chemical treatments. Significant topographical changes were observed following exposure to aqueous solutions of ethylenediaminetetraacetic acid (EDTA) or highly concentrated sodium fluoride (NaF). Both treatments resulted in the apparent loss of the hydroxyapatite mineral platelets on a timescale of a few seconds. Collagen fibrils situated beneath the overlying mineral platelets were clearly exposed and could be resolved with high spatial resolution in the acquired AFM images. Time-dependent mass loss experiments revealed that the applied agents (NaF or EDTA) had very different resulting effects. Despite the fact that the two treatments exhibited nearly identical results following examination by AFM, bulk bone samples treated with EDTA exhibited a ∼70% mass loss after 72 h, whereas for the NaF-treated samples, the mass loss was only of the order of ∼10%. These results support those obtained from previous mechanical testing experiments, suggesting that enhanced formation of superficial fluoroapatite dramatically weakens the protein-hydroxyapatite interfaces. Additionally, we discovered that treatment with aqueous solutions of NaF resulted in the effective extraction of noncollagenous proteins from bone powder.
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Affiliation(s)
- J H Kindt
- Veeco Metrology Inc., 112 Robin Hill Road, Goleta, CA 93117, USA
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39
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Chavassieux P, Seeman E, Delmas PD. Insights into material and structural basis of bone fragility from diseases associated with fractures: how determinants of the biomechanical properties of bone are compromised by disease. Endocr Rev 2007; 28:151-64. [PMID: 17200084 DOI: 10.1210/er.2006-0029] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Minimal trauma fractures in bone diseases are the result of bone fragility. Rather than considering bone fragility as being the result of a reduced amount of bone, we recognize that bone fragility is the result of changes in the material and structural properties of bone. A better understanding of the contribution of each component of the material composition and structure and how these interact to maintain whole bone strength is obtained by the study of metabolic bone diseases. Disorders of collagen (osteogenesis imperfecta and Paget's disease of bone), mineral content, composition and distribution (fluorosis and osteomalacia); diseases of high remodeling (postmenopausal osteoporosis, hyperparathyroidism, and hyperthyroidism) and low remodeling (osteopetrosis, pycnodysostosis); and other diseases (idiopathic male osteoporosis, corticosteroid-induced osteoporosis) produce abnormalities in the material composition and structure that lead to bone fragility. Observations in patients and in animal models provide insights on the biomechanical consequences of these illnesses and the nature of the qualities of bone that determine its strength.
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Affiliation(s)
- P Chavassieux
- Institut National de la Santé et de la Recherche Médicale Unit 831, Pavillon F, Hopital E. Herriot, 69437 Lyon Cedex 08, France
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40
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Wang X, Yoon YJ, Ji H. A novel scratching approach for measuring age-related changes in the in situ toughness of bone. J Biomech 2006; 40:1401-4. [PMID: 16901491 PMCID: PMC1866292 DOI: 10.1016/j.jbiomech.2006.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2006] [Accepted: 06/11/2006] [Indexed: 11/26/2022]
Abstract
A scratch test using a nanoindentation system was proposed in this study to assess the age-related changes in the in situ toughness of bone matrix at ultrastructural levels. A tissue removal energy density (u(r)) was defined and estimated as the work done by the scratch (U(T)) divided by the total volume of the scratch groove (u(s)). The value of u(s) was used as a relative measure of the in situ toughness of the tissue. Human cortical bone specimens obtained from middle-aged (between 49 and 59 years old) and elderly groups (over 69 years old) were tested using this technique. A significant difference in the estimated removal energy density (u(s)) in the secondary osteons was found between the middle-aged and elderly groups (5.49+/-0.696 vs. 4.09+/-1.30 N/mm(2), respectively).
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Affiliation(s)
- X Wang
- Department of Mechanical Engineering and Biomechanics, The University of Texas at San Antonio, 6900 North Loop 1604 West, San Antonio, TX 78249, USA.
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41
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Nyman JS, Reyes M, Wang X. Effect of ultrastructural changes on the toughness of bone. Micron 2005; 36:566-82. [PMID: 16169742 DOI: 10.1016/j.micron.2005.07.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2005] [Revised: 06/27/2005] [Accepted: 07/04/2005] [Indexed: 11/20/2022]
Abstract
The ultrastructure of bone can be considered as a conjunction between the biology and the biomechanics of the tissue. It is the result of cellular and molecular activities of bone formation, and its organization dominates the mechanical behavior of bone. Following this perspective, the objective of this review is to provide a current understanding of bone ultrastructure and its relationships with the toughness of the tissue. Therefore, we first provide a discussion on the organization of bone constituents, namely collagen, mineral, and water. Then, we present evidence on how the toughness of bone relates to its ultrastructure through the formation of micro damage. In addition, attention is given to how damage accumulation serves as a toughening mechanism. Finally, we describe how changes in the ultrastructure-caused by osteogenesis imperfecta, gamma irradiation, fluoride treatment, and aging affect the toughness and competence of bone.
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Affiliation(s)
- Jeffry S Nyman
- Mechanical Engineering and Biomechanics, University of Texas at San Antonio, 6900 North Loop 1604 West, San Antonio, TX 78249, USA
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42
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Kikuchi M, Matsumoto HN, Yamada T, Koyama Y, Takakuda K, Tanaka J. Glutaraldehyde cross-linked hydroxyapatite/collagen self-organized nanocomposites. Biomaterials 2004; 25:63-9. [PMID: 14580909 DOI: 10.1016/s0142-9612(03)00472-1] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To control the mechanical properties and biodegradability of self-organized hydroxyapatite/collagen (HAp/Col) nanocomposites, cross-linkage was introduced into the composites with glutaraldehyde (GA). The HAp/Col composite suspensions, prepared by a simultaneous titration method and aged for 3h, were cross-linked with the reagents for 10min under vigorous stirring. The precipitates obtained were filtrated and compacted by dehydration under a uniaxial pressure. The particle size distribution, 3-point bending strength, contained water amount and swelling ratio of the composites were examined as a function of cross-linkage amount; the biodegradability was estimated by animal tests using rabbits. As regards the cross-linked composites, no long-rage alignment of HAp crystals along collagen molecules was found with a transmission electron microscope, suggesting that the cross-linking reagents suppressed their long-range self-organization mechanism. The 3-point bending strength increased with the GA content and took a maximal value at 1.35mmol/g(col). The animal tests indicated no toxicity and osteoclastic resorption with good osteoconductivity. The resorption rate was decreased with increasing GA concentration. These results suggest that GA cross-linkage controls mechanical properties and resorption rate without reducing high biocompatibility of the composite.
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Affiliation(s)
- Masanori Kikuchi
- Biomaterials Center, National Institute for Materials Science, 1-1, Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
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43
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Itoh S, Kikuchi M, Takakuda K, Nagaoka K, Koyama Y, Tanaka J, Shinomiya K. Implantation study of a novel hydroxyapatite/collagen (HAp/col) composite into weight-bearing sites of dogs. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2003; 63:507-15. [PMID: 12209894 DOI: 10.1002/jbm.10305] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A hydroxyapatite/type I collagen (HAp/Col) composite, aligning hydroxyapatite nanocrystals along collagen molecules, has been prepared. The biocompatibility, osteoconductive activity, and efficacy as a carrier of rhBMP-2 of this novel biomaterial implanted in the weight-bearing site have been examined. The HAp/Col implants (15 mm in diameter and 20 mm in length) with a surface cross-linked layer containing rhBMP-2 (0 or 400 microg/ml) were implanted into bone defects of tibiae in three beagle dogs and fixed according to the Ilizarov method. As a control, bone defects of 20 mm in two beagle dogs did not receive implants, and the dogs were allowed to walk using an Ilizarov extraskeletal fixator. The specimens were removed from one dog in each group after 12 weeks. Also, the Ilizarov fixators in the rhBMP-treated dogs were removed after 12 weeks, after which full weight bearing started. The specimens were further taken out after 18 and 24 weeks in the rhBMP-treated and non-rhBMP-treated dogs, and after 24 weeks in the control group. The change of bone mineral density, as well as radiological and histological findings, suggest that the implants are able to induce bone remodeling units and are a superior carrier of rhBMP-2 due to the stimulation of early callus and new bone formation.
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Affiliation(s)
- Soichiro Itoh
- Department of Orthopaedic Surgery and Biomechanical Engineering, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
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44
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Koutsopoulos S. Synthesis and characterization of hydroxyapatite crystals: a review study on the analytical methods. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2002; 62:600-12. [PMID: 12221709 DOI: 10.1002/jbm.10280] [Citation(s) in RCA: 707] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
For the synthesis of hydroxyapatite crystals from aqueous solutions three preparation methods were employed. From the experimental processes and the characterization of the crystals it was concluded that aging and precipitation kinetics are critical for the purity of the product and its crystallographic characteristics. The authentication details are presented along with the results from infrared spectroscopy, X-ray powder diffraction, Raman spectroscopy, transmission and scanning electron photographs, and chemical analysis. Analytical data for several calcium phosphates were collected from the literature, extensively reviewed, and the results were grouped and presented in tables to provide comparison with the data obtained here.
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Affiliation(s)
- S Koutsopoulos
- Department of Chemistry, University of Patras, GR-26500 Patras, Greece.
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45
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Yamashita J, Li X, Furman BR, Rawls HR, Wang X, Agrawal CM. Collagen and bone viscoelasticity: a dynamic mechanical analysis. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2002; 63:31-6. [PMID: 11787026 DOI: 10.1002/jbm.10086] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to explore the effects of changes in Type I collagen on the viscoelasticity of bone. Bone coupons were heated at either 100 or 200 degrees C to induce the thermal denaturation of Type I collagen. Half of these specimens were rehydrated after heat treatment; the other half were tested in a dry condition. The degree of denatured collagen (DC%) was analyzed by a selective digestion technique with the use of alpha-chymotrypsin. Isothermal (37 degrees C) and variable temperature tests (scans from 35 to 200 degrees C) were performed with the use of a dynamic mechanical analyzer to evaluate changes in bone viscoelastic properties as a function of collagen damage, specifically, changes in the loss factor (tan delta) and storage modulus (E') were assessed. Significant collagen denaturation occurred only when bone was heated at 200 degrees C irrespective of the hydration condition. Also, DC% did not show a significant effect on tan delta. However, higher values of tan delta were observed in wet samples compared to dry specimens. The temperature-scan tests revealed that the hydration condition, but not DC%, significantly affected the behavior of tan delta. However, E' was not strongly influenced either by DC% or by water content. These results suggest that at a constant frequency the denaturation of collagen triple-helical molecules may have few effects on the viscoelasticity of bone, but moisture may play a prominent role in determining this property.
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Affiliation(s)
- Junro Yamashita
- Center for Clinical Bioengineering, The University of Texas Health Science Center, San Antonio, Texas 78284, USA
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46
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Kikuchi M, Itoh S, Ichinose S, Shinomiya K, Tanaka J. Self-organization mechanism in a bone-like hydroxyapatite/collagen nanocomposite synthesized in vitro and its biological reaction in vivo. Biomaterials 2001; 22:1705-11. [PMID: 11396873 DOI: 10.1016/s0142-9612(00)00305-7] [Citation(s) in RCA: 724] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
When bone is lost due to injury and/or illness, the defects are generally filled with natural bone because artificial bone materials have problems of bioaffinity. However, natural bone also has supply and infection problems. If an artificial material has the same biological properties as bone, it can replace natural bone for grafting. We synthesized a hydroxyapaite (HAp) and collagen (Col) composite by a simultaneous titration coprecipitation method using Ca(OH)2, H3PO4 and porcine atelocollagen as starting materials. The composite obtained showed a self-organized nanostructure similar to bone assembled by the chemical interaction between HAp and Col. The consolidated composite by a cold isostatic pressure of 200 MPa indicated a quarter of the mechanical strength of bone. It also indicated the same biological properties as grafted bone: The material was resorbed by phagocytosis of osteoclast-like cells and conducted osteoblasts to form new bone in the surrounding area. This HAp/Col composite having similar nanostructure and composition can replace autologous bone grafts.
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Affiliation(s)
- M Kikuchi
- National Institute for Research in Inorganic Materials, Tsukuba, Ibaraki, Japan.
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47
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Mehta SS, Oz OK, Antich PP. Bone elasticity and ultrasound velocity are affected by subtle changes in the organic matrix. J Bone Miner Res 1998; 13:114-21. [PMID: 9443797 DOI: 10.1359/jbmr.1998.13.1.114] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The mechanical competence of bone can be studied through the measurement of the components of its material elasticity, a property which can vary both in magnitude and in dependence upon orientation (anisotropy). While it is known that the elasticity is largely determined by the mineral constituents of the bone matrix, it is nonetheless clear that it must be also dependent upon the remaining constituents of bone material. In this work, the influence of organic components on the elasticity is explored by altering specific constituents of the bone matrix to varying degrees. This study addresses two questions: first, are the resulting changes in elasticity strongly or weakly dependent upon direction, and second, are they substantially dependent upon the nature and magnitude of the induced matrix alteration? To answer these questions, we performed different chemical manipulations of the bone matrix and measured the changes in elasticity and velocity using the technique of ultrasound critical angle reflectometry. Altering the properties of the organic matrix resulted in substantial and complex changes in the elasticity of bone. The observed changes were strongly dependent upon direction, could not be explained by changes in density alone, and varied strongly with the specific chemical treatment of the matrix. Immersion in urea selectively affected protein components of the organic matrix and resulted in reversible changes in velocity and elasticity, while removal of collagen caused anisotropic decreases and removal of all organic matter caused a collapse of all components of the elasticity. In conclusion, this study confirms that the organic matrix exerts a profound influence on the elasticity and indicates that the measurement of elastic properties at multiple directions is necessary in the assessment of bone mechanical competence.
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Affiliation(s)
- S S Mehta
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75235-9071, USA
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48
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Paschalis EP, DiCarlo E, Betts F, Sherman P, Mendelsohn R, Boskey AL. FTIR microspectroscopic analysis of human osteonal bone. Calcif Tissue Int 1996; 59:480-7. [PMID: 8939775 DOI: 10.1007/bf00369214] [Citation(s) in RCA: 303] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Fourier Transform Infrared Microspectroscopy (FTIRM) has been used to study the changes in mineral and matrix content and composition in replicate biopsies of nonosteoporotic human osteonal bone. Spectral maps in four orthogonal directions (in 10 microm steps) from the centers towards the peripheries of individual osteons were obtained from iliac crest biopsies of two necropsy cases. Mineral to matrix ratios, calculated from the ratio of integrated areas of the phosphate nu1,nu3 band at 900-1200 cm-1 to the amide I band at 1585-1725 cm-1, increased from the center to the periphery of the osteon. The total carbonate (based on the nu2 band at approximately 850-900 cm-1) to phosphate nu1,nu3 ratio decreased as the mineral to matrix ratio increased. Analysis of the nu2 CO32- band with a combination of second-derivative spectroscopy and curve fitting revealed a decrease in "labile" carbonate, a slight decrease in Type A and a slight increase in Type B carbonate from the center to the periphery of the osteon. Similar analysis of the components of the nu1,nu3 phosphate band with a combination of second-derivative spectroscopy and curve fitting revealed the presence of 11 major underlying moieties. These components were assigned by comparison with published frequencies for apatite and acid-phosphate containing calcium phosphates. The most consistent variations were alterations in the relative percent areas of bands at approximately 1020 and approximately 1030 cm-1, which had previously been assigned to nonstoichiometric and stoichiometric apatites, respectively. This ratio was used as an index of variation in crystal perfection throughout the osteon. This ratio decreased as the mineral to matrix ratio increased. The reproducibility of these parameters at multiple sites in multiple biopsies suggests their applicability for the analysis of mineral changes in disease.
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Affiliation(s)
- E P Paschalis
- The Hospital for Special Surgery, New York, New York, USA
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49
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Gustafson MB, Martin RB, Gibson V, Storms DH, Stover SM, Gibeling J, Griffin L. Calcium buffering is required to maintain bone stiffness in saline solution. J Biomech 1996; 29:1191-4. [PMID: 8872276 DOI: 10.1016/0021-9290(96)00020-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This work determined whether mineral dissolution due to prolonged testing or storage of bone specimens in normal saline would alter their elastic modulus. In one experiment, small pieces of equine third metacarpal bone were soaked in normal saline supplemented with varying amounts of CaCl2. Changing Ca ion concentrations in the bath were monitored and the equilibrium concentration was determined. In a second experiment, the elastic moduli of twenty 4 x 10 x 100 mm equine third metacarpal beams were determined non-destructively in four-point bending. Half the beams were then soaked for 10 days in normal saline, and the other half in saline buffered to the bone mineral equilibrium point with Ca ions. Modulus measurements were repeated at 6 and 10 days. The equilibrium Ca ion concentration for bone specimens was found to be 57.5 mg l-1. The modulus of bone specimens soaked in normal saline significantly diminished 2.4%, whereas the modulus of those soaked in calcium-buffered saline did not change significantly.
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Affiliation(s)
- M B Gustafson
- Orthopaedic Research Laboratories, School of Medicine, University of California at Davis, 95616, USA
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50
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Walsh WR, Christiansen DL. Demineralized bone matrix as a template for mineral--organic composites. Biomaterials 1995; 16:1363-71. [PMID: 8590762 DOI: 10.1016/0142-9612(95)96871-v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mineralizing biological tissues are complex bioceramic-biopolymer composites engineered for a variety of functions. The organic and inorganic constituents, morphology, location, orientation, crystallinity and interactions exhibit materials or extremely fine microstructure, unique mechanical and physical properties with high strength and fracture toughness compared to the individual constituents. An understanding of mineralization, ultrastructural organization and interfacial bonding forces in mineralizing biological composite tissues, such as bone, may provide new strategies and techniques for the production of a novel class of man-made organic-ceramic composites. The present study explores the use of the organic matrix remaining after removal of the mineral phase by chelation with EDTA or solubilizing in HCl as a template for mineral deposition and the production of mineral-organic composites. Different pH conditions are employed to alter the inorganic phase which is deposited within the organic matrix. Mechanical testing and ultrastructural evaluations are carried out for characterization.
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Affiliation(s)
- W R Walsh
- Department of Orthopaedics, Rhode Island Hospital, Brown University School of Medicine, Providence, USA
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