Special Issue "Composite Materials in Skeletal Engineering"
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A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Material Sciences and Nanotechnology".
Deadline for manuscript submissions: closed (29 February 2012)
Special Issue Editors
Guest Editor
Prof. Dr. Mohamed N. Rahaman
Department of Materials Science and Engineering, Center for Bone and Tissue Repair and Regeneration, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop Avenue, Rolla, Missouri 65409-0340, USA
Website: http://www.mst.edu/~rahaman/
E-Mail: rahaman@mst.edu
Guest Editor
Dr. B. Sonny Bal
Department of Orthopaedic Surgery, University of Missouri School of Medicine, Columbia, MO 65201, USA
E-Mail: balb@health.missouri.edu
Special Issue Information
Dear Colleagues,
Skeletal tissues, such as bone, muscles, tendon, and ligaments represent a remarkable feat of nature’s engineering. These tissues are designed for a lifetime of repetitive, complex loading, with the capacity for healing and repair. Reproducing skeletal tissues with synthetic materials is an engineering challenge.
Composite materials provide a wider range of properties than the basic classes of materials (metals, ceramics, and polymers), so they offer an attractive approach for mimicking the properties of skeletal tissues. Interest in nanocomposites stems from the significant property advantages which they can offer over their conventional counterparts. The recently-developed field of tissue-engineering is attracting considerable interest for the regeneration of diseased or damaged tissues; it is probable that composite materials will play a significant role in repairing or restoring human skeletal tissue.
In this issue, recent advances in the development of composite materials for the repair and regeneration of skeletal tissues are emphasized and discussed. Guest authors describe advances in the fabrication, design, and testing of these materials. It is hoped that this special issue will serve as a platform for the cross-fertilization of ideas and concepts that ultimately lead to products and developments to advance improved skeletal health for humans.
Mohamed N. Rahaman, Ph.D.
B. Sonny Bal, Ph.D.
Guest Editors
Submission
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed Open Access monthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs).
Keywords
- processing and fabrication
- structural, mechanical, and biological properties
- engineered composite tissues
- applications
Published Papers (10 papers)
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Received: 14 July 2010; in revised form: 23 August 2010 / Accepted: 6 September 2010 / Published: 15 September 2010
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Abstract: HCl-demineralized murine lower incisors were implanted intramuscularly into syngeneic BALB/c mice to induce heterotopic osteogenesis. Implants were exposed at the early, preosteogenic stage (4), or at the later, osteogenic stage (12) to the Moloney sarcoma virus (MSV), which within 3–4 days results in a sarcoma. The yield of bone induction was determined by weight of dry bone mass following NaOH hydrolysis of soft tissues. To verify the effect of this sarcoma on orthotopic local femoral bone, the dry mass of the tumor-exposed femora was measured and compared with the weight of MSV-unexposed contralateral controls. MSV-sarcoma or cells involved with their spontaneous rejection have a stimulatory effect on the periosteal membrane of the tumor-adjacent femoral bones, increasing their dry mass on average by 18%. No stimulatory effect on heterotopic bone induction was observed when the MSV sarcoma grew during the early, preosteogenic stage (4 onward), but when the tooth matrix had been exposed to such tumor at the already bone-forming stage, (12 onward), the yield of bone induction was enhanced. Thus, it is postulated that lesions induced by MSV during the early, preosteogenic stage inhibit recruitment of osteoprogenitor cells or degrade Bone Morphogenetic Proteins (BMPs) released by matrix resorbing inflammatory cells, whereas when acting on already existing bone they have a stimulatory effect.
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Received: 2 November 2010; in revised form: 4 January 2011 / Accepted: 24 January 2011 / Published: 25 January 2011
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Abstract: Macroporous scaffolds with controllable pore structure and mechanical properties were fabricated by a porogen fusion technique. Biodegradable material poly (D, L-lactide) (PDLLA) was used as the scaffold matrix. The effects of porogen size, PDLLA concentration and hydroxyapatite (HA) content on the scaffold morphology, porosity and mechanical properties were investigated. High porosity (90% and above) and highly interconnected structures were easily obtained and the pore size could be adjusted by varying the porogen size. With the increasing porogen size and PDLLA concentration, the porosity of scaffolds decreases, while its mechanical properties increase. The introduction of HA greatly increases the impact on pore structure, mechanical properties and water absorption ability of scaffolds, while it has comparatively little influence on its porosity under low HA contents. These results show that by adjusting processing parameters, scaffolds could afford a controllable pore size, exhibit suitable pore structure and high porosity, as well as good mechanical properties, and may serve as an excellent substrate for bone tissue engineering.
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Received: 25 July 2011; in revised form: 23 September 2011 / Accepted: 11 October 2011 / Published: 25 October 2011
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Abstract: This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp), tricalcium phosphate (β-TCP), and HAp/β-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis) and nanoparticles of tricalcium phosphate (β-TCP) and hydroxyapatite (HAp) suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/β-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0 wt% acetic acid. The properties of the spinning solutions were examined. Chitosan fibers modified with nanoparticles of HAp/β-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers.
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Gabriela Ciapetti, Donatella Granchi, Valentina Devescovi, Serena R. Baglio, Elisa Leonardi, Desirèe Martini, Maria Jesus Jurado, Beatriz Olalde, Ilaria Armentano, Josè M. Kenny, Frank X. Walboomers, Josè Inaki Alava and Nicola Baldini
Received: 27 December 2011; in revised form: 13 February 2012 / Accepted: 14 February 2012 / Published: 22 February 2012
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Abstract: In bone engineering, the adhesion, proliferation and differentiation of mesenchymal stromal cells rely on signaling from chemico-physical structure of the substrate, therefore prompting the design of mimetic “extracellular matrix”-like scaffolds. In this study, three-dimensional porous poly-L-lactic acid (PLLA)-based scaffolds have been mixed with different components, including single walled carbon nanotubes (CNT), micro-hydroxyapatite particles (HA), and BMP2, and treated with plasma (PT), to obtain four different nanocomposites: PLLA + CNT, PLLA + CNTHA, PLLA + CNT + HA + BMP2 and PLLA + CNT + HA + PT. Adult bone marrow mesenchymal stromal cells (MSCs) were derived from the femur of orthopaedic patients, seeded on the scaffolds and cultured under osteogenic induction up to differentiation and mineralization. The release of specific metabolites and temporal gene expression profiles of marrow-derived osteoprogenitors were analyzed at definite time points, relevant to in vitro culture as well as in vivo differentiation. As a result, the role of the different biomimetic components added to the PLLA matrix was deciphered, with BMP2-added scaffolds showing the highest biomimetic activity on cells differentiating to mature osteoblasts. The modification of a polymeric scaffold with reinforcing components which also work as biomimetic cues for cells can effectively direct osteoprogenitor cells differentiation, so as to shorten the time required for mineralization.
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Received: 1 December 2011; in revised form: 4 January 2012 / Accepted: 20 February 2012 / Published: 12 March 2012
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Abstract: In this study, vascular stents were fabricated from poly (lactide-ε-caprolactone)/collagen/nano-hydroxyapatite (PLCL/Col/nHA) by electrospinning, and the surface morphology and breaking strength were observed or measured through scanning electron microscopy and tensile tests. The anti-clotting properties of stents were evaluated for anticoagulation surfaces modified by the electrostatic layer-by-layer self-assembly technique. In addition, nano-composite scaffolds of poly (lactic-co-glycolic acid)/polycapr-olactone/nano-hydroxyapatite (PLGA/PCL/nHA) loaded with the vascular stents were prepared by thermoforming-particle leaching and their basic performance and osteogenesis were tested in vitro and in vivo. The results show that the PLCL/Col/nHA stents and PLGA/PCL/nHA nano-composite scaffolds had good surface structures, mechanical properties, biocompatibility and could guide bone regeneration. These may provide a new way to build vascularized-tissue engineered bone to repair large bone defects in bone tissue engineering.
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Received: 14 February 2012; in revised form: 3 March 2012 / Accepted: 19 March 2012 / Published: 22 March 2012
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Abstract: Cooperative effects of magnesium ions and acidic polypeptides originating from a family of proteins known as Asprich (mollusk Atrina rigida) were studied. In our previous studies, these two acidic polypeptides were found to be effective in controlling the morphology of the calcium carbonate mineral, the main inorganic constituent of prismatic layer of the mollusk shell. Since these Asprich sequences are believed to contain a putative magnesium binding domain, the morphology-controlling effects were further investigated with the addition of magnesium ions. The mineral morphology was dramatically changed by the combined influence of each polypeptides and the magnesium ions, substantiating the recognized importance of magnesium in the formation of calcium carbonate-based biominerals.
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Received: 30 January 2012; in revised form: 15 March 2012 / Accepted: 23 March 2012 / Published: 5 April 2012
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Abstract: In the present study, the mechanical properties of self-compacting concrete were investigated after the addition of different amounts of ZnO nanoparticles. The zinc oxide nanoparticles, with an average particle size of about 30 nm, were synthesized and their properties studied with the help of a scanning electron microscope (SEM) and X-ray diffraction. The prepared nanoparticles were partially added to self-compacting concrete at different concentrations (0.05, 0.1, 0.2, 0.5 and 1.0%), and the mechanical (flexural and split tensile) strength of the specimens measured after 7, 14, 21 and 28 days, respectively. The present results have shown that the ZnO nanoparticles were able to improve the flexural strength of self-compacting concrete. The increased ZnO content of more than 0.2% could increase the flexural strength, and the maximum flexural and split tensile strength was observed after the addition of 0.5% nanoparticles. Finally, ZnO nanoparticles could improve the pore structure of the self-compacted concrete and shift the distributed pores to harmless and less-harmful pores, while increasing mechanical strength.
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Received: 24 March 2012; in revised form: 25 April 2012 / Accepted: 3 May 2012 / Published: 9 May 2012
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Abstract: To establish the methods of demonstrating early fixation of metal implants to bone, one side of a Cobalt-Chromium (CoCr) based alloy implant surface was seeded with rabbit marrow mesenchymal cells and the other side was left unseeded. The mesenchymal cells were further cultured in the presence of ascorbic acid, β-glycerophosphate and dexamethasone, resulting in the appearance of osteoblasts and bone matrix on the implant surface. Thus, we succeeded in generating tissue-engineered bone on one side of the CoCr implant. The CoCr implants were then implanted in rabbit bone defects. Three weeks after the implantation, evaluations of mechanical test, undecalcified histological section and electron microscope analysis were performed. Histological and electron microscope images of the tissue engineered surface exhibited abundant new bone formation. However, newly formed bone tissue was difficult to detect on the side without cell seeding. In the mechanical test, the mean values of pull-out forces were 77.15 N and 44.94 N for the tissue-engineered and non-cell-seeded surfaces, respectively. These findings indicate early bone fixation of the tissue-engineered CoCr surface just three weeks after implantation.
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Received: 12 April 2012; in revised form: 3 May 2012 / Accepted: 10 May 2012 / Published: 21 May 2012
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Abstract: Novel hybrid xerogel materials were synthesized by a sol-gel procedure. n-octadecyltriethoxysilane was co-condensed with and without different cross-linkers using Q0 and T0 mono-functionalized organosilanes in the presence of n-hexadecylamine with different hydroxyl silica functional groups at the surface. These polymer networks have shown new properties, for example, a high degree of cross-linking and hydrolysis. Two different synthesis steps were carried out: simple self-assembly followed by sol-gel transition and precipitation of homogenous sols. Due to the lack of solubility of these materials, the compositions of the new materials were determined by infrared spectroscopy, 13C and 29Si CP/MAS NMR spectroscopy and scanning electron microscopy.
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Received: 18 April 2012; in revised form: 25 May 2012 / Accepted: 30 May 2012 / Published: 21 June 2012
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Abstract: Bone repair or regeneration is a common and complicated clinical problem in orthopedic surgery. The importance of natural polymers, such as microcrystalline chitosan, and minerals such as HAp and β-TCP, has grown significantly over the last two decades due to their renewable and biodegradable source, increasing the knowledge and functionality of composites in technological and biomedical applications. This study compares the biodegradation process, bioactivity, structure, morphology, and mechanical properties of microcrystalline chitosan and microcrystalline chitosan/β-TCP complex; the latter according to the new method of preparation. The complex showed a homogeneous network structure with regular pores, good bioactivity, even after 60 days of conducting the hydrolytic and enzymatic degradation process, showing a bacteriostatic and bactericidal activity. The complex indicates that it could be used successfully as a base for implants and scaffolds production in orthopedic surgery.
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Last update: 26 September 2012
