Special Issue "Spotlight on Bioactive Glasses and Their Related Composites"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Biomaterials".

Deadline for manuscript submissions: 30 November 2019.

Special Issue Editor

Prof. Valeria Cannillo
E-Mail Website
Guest Editor
Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Italy
Interests: biomaterials; bioactive glasses; composites; surface coatings; materials modeling

Special Issue Information

Dear Colleagues,

Bioactive glasses are receiving increasing attention due to their extraordinary properties. In fact, the demand for new materials suitable for the healing of tissue and bone is dramatically increasing due to world population ageing. For this reason, in the last decades, several studies have attempted to produce high performance materials with enhanced biological responses.

Bioactive glasses are an attractive choice, as they are typically able to bond to bone more rapidly than other bioceramics. Since their discovery, bioactive glasses have opened unimaginable scenarios in the field of tissue regeneration, mainly thanks to their osteoinductive and osteoconductive characteristics and also their capability of bonding to soft connective tissues.

Moreover, it is possible to tailor the properties of such materials by selectively varying the composition and thus controlling the degradation rate in accordance with the rate of new tissue formation. Furthermore, the addition of specific ions can have a beneficial effect, for example in terms of antibacterial properties. Additionally, bioactive glasses can promote angiogenesis, neovascularisation, osteoblasts proliferation, new bone growth, hemostasis and even wound healing.

The combination, by varying the volume fractions of the two constituents, of bioactive glass with other materials such as polymers opens new possibilities for the production of hybrid composites with properties tailored for specific clinical applications.

Bioglasses and their related composites can be produced in varoius forms, such as granules, scaffolds, moldable implants, and surface coatings, useful for many applications in tissue engineering and regenerative medicine.

For these reasons, it is my immense pleasure to invite you to submit a manuscript to this Special Issue. Full research articles, short communications and reviews are welcome, related (but not limited to) the following topics: design and production of innovative bioactive glasses and/or their related composites; in vivo and in vitro studies; characterization and modeling of properties; functionalization of these systems.

Assoc. Prof. Valeria Cannillo
Guest Editor

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Bioactive glasses
  • Bioactive composites
  • Scaffolds
  • Surface coatings
  • In vivo and in vitro tests
  • Additive manufacturing
  • Materials modeling
  • Tissue engineering
  • Regenerative medicine
  • Drug delivery

Published Papers (10 papers)

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Research

Open AccessArticle
Development and Biocompatibility of Collagen-Based Composites Enriched with Nanoparticles of Strontium Containing Mesoporous Glass
Materials 2019, 12(22), 3719; https://doi.org/10.3390/ma12223719 - 11 Nov 2019
Abstract
In the last years bone tissue engineering has been increasingly indicated as a valid solution to meet the challenging requirements for a healthy bone regeneration in case of bone loss or fracture. In such a context, bioactive glasses have already proved their great [...] Read more.
In the last years bone tissue engineering has been increasingly indicated as a valid solution to meet the challenging requirements for a healthy bone regeneration in case of bone loss or fracture. In such a context, bioactive glasses have already proved their great potential in promoting the regeneration of new bone tissue due to their high bioactivity. In addition, their composition and structure enable us to incorporate and subsequently release therapeutic ions such as strontium, enhancing the osteogenic properties of the material. The incorporation of these inorganic systems in polymeric matrices enables the formulation of composite systems suitable for the design of bone scaffolds or delivery platforms. Among the natural polymers, type I collagen represents the main organic phase of bone and thus is a good candidate to develop biomimetic bioactive systems for bone tissue regeneration. However, alongside the specific composition and structure, the key factor in the design of new biosystems is creating a suitable interaction with cells and the host tissue. In this scenario, the presented study aimed at combining nano-sized mesoporous bioactive glasses produced by means of a sol–gel route with type I collagen in order to develop a bioactive hybrid formulation suitable for bone tissue engineering applications. The designed system has been fully characterized in terms of physico-chemical and morphological analyses and the ability to release Sr2+ ions has been studied observing a more sustained profile in presence of the collagenous matrix. With the aim to improve the mechanical and thermal stability of the resulting hybrid system, a chemical crosslinking approach using 4-star poly (ethylene glycol) ether tetrasuccinimidyl glutarate (4-StarPEG) has been explored. The biocompatibility of both non-crosslinked and 4-StarPEG crosslinked systems was evaluated by in vitro tests with human osteoblast-like MG-63 cells. Collected results confirmed the high biocompatibility of composites, showing a good viability and adhesion of cells when cultured onto the biomaterial samples. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessArticle
Correlation of Morphology and In-Vitro Degradation Behavior of Spray Pyrolyzed Bioactive Glasses
Materials 2019, 12(22), 3703; https://doi.org/10.3390/ma12223703 - 09 Nov 2019
Abstract
Bioactive glass (BG) is considered to be one of the most remarkable materials in the field of bone tissue regeneration due to its superior bioactivity. In this study, both un-treated and polyethylene glycols (PEG)-treated BG particles were prepared using a spray pyrolysis process [...] Read more.
Bioactive glass (BG) is considered to be one of the most remarkable materials in the field of bone tissue regeneration due to its superior bioactivity. In this study, both un-treated and polyethylene glycols (PEG)-treated BG particles were prepared using a spray pyrolysis process to study the correlation between particle morphology and degradation behavior. The phase compositions, surface morphologies, inner structures, and specific surface areas of all BG specimens were examined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption/desorption, respectively. Simulated body fluid (SBF) immersion evaluated the assessments of bioactivity and degradation behavior. The results demonstrate three particle morphologies of solid, porous, and hollow factors. The correlation between porosity, bioactivity, and degradation behavior was discussed. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessFeature PaperArticle
Advanced Open-Celled Structures from Low-Temperature Sintering of a Crystallization-Resistant Bioactive Glass
Materials 2019, 12(22), 3653; https://doi.org/10.3390/ma12223653 - 06 Nov 2019
Abstract
Most materials for bone tissue engineering are in form of highly porous open-celled components (porosity >70%) developed by means of an adequate coupling of formulations and manufacturing technologies. This paper is dedicated to porous components from BGMS10 bioactive glass, originally designed to undergo [...] Read more.
Most materials for bone tissue engineering are in form of highly porous open-celled components (porosity >70%) developed by means of an adequate coupling of formulations and manufacturing technologies. This paper is dedicated to porous components from BGMS10 bioactive glass, originally designed to undergo viscous flow sintering without crystallization, which is generally known to degrade the bioactivity of 45S5 bioglass. The adopted manufacturing technologies were specifically conceived to avoid any contamination and give excellent control on the microstructures by simple operations. More precisely, ‘green’ components were obtained by digital light processing and direct foaming of glass powders suspended in a photosensitive organic binder or in an aqueous solution, activated with an organic base, respectively. Owing to characteristic quite large sintering window of BGMS10 glass, sintering at 750 °C caused the consolidation of the structures generated at room temperature, without any evidence of viscous collapse. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessArticle
Human Mesenchymal Stem Cell Combined with a New Strontium-Enriched Bioactive Glass: An ex-vivo Model for Bone Regeneration
Materials 2019, 12(21), 3633; https://doi.org/10.3390/ma12213633 - 05 Nov 2019
Abstract
A 3D cellular model that mimics the potential clinical application of a biomaterial is here applied for the first time to a bioactive glass, in order to assess its biological potential. A recently developed bioactive glass (BGMS10), whose composition contained strontium and magnesium, [...] Read more.
A 3D cellular model that mimics the potential clinical application of a biomaterial is here applied for the first time to a bioactive glass, in order to assess its biological potential. A recently developed bioactive glass (BGMS10), whose composition contained strontium and magnesium, was produced in the form of granules and fully investigated in terms of biocompatibility in vitro. Apart from standard biological characterization (Simulated Body Fluid (SBF) testing and biocompatibility as per ISO10993), human bone marrow mesenchymal stromal/stem cells (BM-MSCs) were used to investigate the performance of the bioactive glass granules in an innovative 3D cellular model. The results showed that BGMS10 supported human BM-MSCs adhesion, colonization, and bone differentiation. Thus, bioactive glass granules seem to drive osteogenic differentiation and thus look particularly promising for orthopedic applications, bone tissue engineering and regenerative medicine. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessArticle
The Implantation of Bioactive Glass Granules Can Contribute the Load-Bearing Capacity of Bones Weakened by Large Cortical Defects
Materials 2019, 12(21), 3481; https://doi.org/10.3390/ma12213481 - 24 Oct 2019
Abstract
Bioactive glass (BAG) granules (S53P4) have shown good clinical results in one-stage treatment of osteomyelitis. During this treatment, a cortical window is created, and infected bone is debrided, which results in large defects that affect the mechanical properties of the bone. This study [...] Read more.
Bioactive glass (BAG) granules (S53P4) have shown good clinical results in one-stage treatment of osteomyelitis. During this treatment, a cortical window is created, and infected bone is debrided, which results in large defects that affect the mechanical properties of the bone. This study aimed to evaluate the role of BAG granules in load-bearing bone defect grafting. First, the influence of the geometry of the cortical window on the bone bending stiffness and estimated failure moments was evaluated using micro finite element analysis (µFE). This resulted in significant differences between the variations in width and length. In addition, µFE analysis showed that BAG granules contribute to bearing loads in simulated compression of a tibia with a defect grafted with BAG and a BAG and bone morsel mixture. These mixtures potentially can unload the cortical bone that is weakened by a large defect directly after the operation by up to approximately 25%, but only in case of optimal load transfer through the mixture. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessArticle
Elastic Mechanical Properties of 45S5-Based Bioactive Glass–Ceramic Scaffolds
Materials 2019, 12(19), 3244; https://doi.org/10.3390/ma12193244 - 04 Oct 2019
Abstract
Porosity is recognized to play a key role in dictating the functional properties of bioactive scaffolds, especially the mechanical performance of the material. The mechanical suitability of brittle ceramic and glass scaffolds for bone tissue engineering applications is usually evaluated on the basis [...] Read more.
Porosity is recognized to play a key role in dictating the functional properties of bioactive scaffolds, especially the mechanical performance of the material. The mechanical suitability of brittle ceramic and glass scaffolds for bone tissue engineering applications is usually evaluated on the basis of the compressive strength alone, which is relatively easy to assess. This work aims to investigate the porosity dependence of the elastic properties of silicate scaffolds based on the 45S5 composition. Highly porous glass–ceramic foams were fabricated by the sponge replica method and their elastic modulus, shear modulus, and Poisson’s ratio were experimentally determined by the impulse excitation technique; furthermore, the failure strength was quantified by compressive tests. As the total fractional porosity increased from 0.52 to 0.86, the elastic and shear moduli decreased from 16.5 to 1.2 GPa and from 6.5 to 0.43 GPa, respectively; the compressive strength was also found to decrease from 3.4 to 0.58 MPa, whereas the Poisson’s ratio increased from 0.2692 to 0.3953. The porosity dependences of elastic modulus, shear modulus and compressive strength obeys power-law models, whereas the relationship between Poisson’s ratio and porosity can be described by a linear approximation. These relations can be useful to optimize the design and fabrication of porous biomaterials as well as to predict the mechanical properties of the scaffolds. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessCommunication
A New Bioactive Glass/Collagen Hybrid Composite for Applications in Dentistry
Materials 2019, 12(13), 2079; https://doi.org/10.3390/ma12132079 - 28 Jun 2019
Cited by 3
Abstract
Bioactive glasses (BGs) are currently employed in a wide range of medical and dentistry applications by virtue of their bone-bonding ability. The incorporation of BGs into a collagen matrix may be used to combine the regenerative potential of these materials with the specific [...] Read more.
Bioactive glasses (BGs) are currently employed in a wide range of medical and dentistry applications by virtue of their bone-bonding ability. The incorporation of BGs into a collagen matrix may be used to combine the regenerative potential of these materials with the specific biological advantages of collagen. However, most of the collagen/BG composites reported in the literature are scaffolds and there is a lack of moldable putties or injectable systems. Here, granules of an innovative BG containing strontium and magnesium were mixed with collagen and PEG to obtain a putty (BGMS/C) suitable for dental applications. For the sake of comparison, granules of 45S5 Bioglass®, the gold standard among BGs, were used to prepare a 45S5/collagen putty. Both the composites were evaluated in vitro with respect to murine fibroblasts. The materials showed an excellent biocompatibility, making them interesting for possible applications in dentistry and reconstructive surgery. Moreover, BGMS/C seems to stimulate cell proliferation. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessArticle
Aging of Bioactive Glass-Based Foams: Effects on Structure, Properties, and Bioactivity
Materials 2019, 12(9), 1485; https://doi.org/10.3390/ma12091485 - 07 May 2019
Abstract
Bioactive glasses (BG) possess significant bone-bonding and osteogenic properties that support their use for bone defects repair in orthopaedic and dental procedures. Recent advancement enables the manufacturing of BG-based scaffolds providing structural support during bone regeneration. Despite the wide number of studies on [...] Read more.
Bioactive glasses (BG) possess significant bone-bonding and osteogenic properties that support their use for bone defects repair in orthopaedic and dental procedures. Recent advancement enables the manufacturing of BG-based scaffolds providing structural support during bone regeneration. Despite the wide number of studies on BG and BG-based materials, little information on their aging mechanisms and shelf life is available in the literature. In this study, the evolution of chemical species on BG-based foams was investigated via accelerated tests in the presence of CO2 and humidity. The aging process led to the formation of carbonates (Na2CO3 and CaCO3) and hydrocarbonates (NaHCO3). The amount and composition of nucleated species evolved with time, affecting the structure, properties, and bioactivity of the scaffolds. This study provides a first structured report of aging effects on the structure and chemico-physical properties of bioactive glass-based scaffolds, offering an insight about the importance of their storage and packaging. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessArticle
Bone Regeneration by Novel Bioactive Glasses Containing Strontium and/or Magnesium: A Preliminary In-Vivo Study
Materials 2018, 11(11), 2223; https://doi.org/10.3390/ma11112223 - 08 Nov 2018
Cited by 5
Abstract
In this work, a set of novel bioactive glasses have been tested in vivo in an animal model. The new compositions, characterized by an exceptional thermal stability and high in vitro bioactivity, contain strontium and/or magnesium, whose biological benefits are well documented in [...] Read more.
In this work, a set of novel bioactive glasses have been tested in vivo in an animal model. The new compositions, characterized by an exceptional thermal stability and high in vitro bioactivity, contain strontium and/or magnesium, whose biological benefits are well documented in the literature. To simulate a long-term implant and to study the effect of the complete dissolution of glasses, samples were implanted in the mid-shaft of rabbits’ femur and analyzed 60 days after the surgery; such samples were in undersized powder form. The statistical significance with respect to the type of bioactive glass was analyzed by Kruskal–Wallis test. The results show high levels of bone remodeling, several new bone formations containing granules of calcium phosphate (sometimes with amounts of strontium and/or magnesium), and the absence of adverse effects on bone processes due to the almost complete glass dissolution. In vivo results confirming the cell culture outcomes of a previous study highlighted that these novel bioglasses had osteostimulative effect without adverse skeletal reaction, thus indicating possible beneficial effects on bone formation processes. The presence of strontium in the glasses seems to be particularly interesting. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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Open AccessArticle
Contrasting In Vitro Apatite Growth from Bioactive Glass Surfaces with that of Spontaneous Precipitation
Materials 2018, 11(9), 1690; https://doi.org/10.3390/ma11091690 - 12 Sep 2018
Cited by 3
Abstract
Body-fluid-exposed bioactive glasses (BGs) integrate with living tissues due to the formation of a biomimetic surface layer of calcium hydroxy-carbonate apatite (HCA) with a close composition to bone mineral. Vast efforts have been spent to understand the mechanisms underlying in vitro apatite mineralization, [...] Read more.
Body-fluid-exposed bioactive glasses (BGs) integrate with living tissues due to the formation of a biomimetic surface layer of calcium hydroxy-carbonate apatite (HCA) with a close composition to bone mineral. Vast efforts have been spent to understand the mechanisms underlying in vitro apatite mineralization, as either formed by direct precipitation from supersaturated solutions, or from BG substrates in a simulated body fluid (SBF). Formally, these two scenarios are distinct and have hitherto been discussed as such. Herein, we contrast them and identify several shared features. We monitored the formation of amorphous calcium phosphate (ACP) and its crystallization into HCA from a Na 2 O–CaO–SiO 2 –P 2 O 5 glass exposed to SBF for variable periods out to 28 days. The HCA growth was assessed semi-quantitatively by Fourier transform infrared spectroscopy and powder X-ray diffraction, with the evolution of the relative apatite content for increasing SBF-exposure periods evaluated against trends in Ca and P concentrations in the accompanying solutions. This revealed a sigmoidal apatite growth behavior, well-known to apply to spontaneously precipitated apatite. The results are discussed in relation to the prevailing mechanism proposed for in vitro HCA formation from silicate-based BGs, where we highlight largely simultaneous growth processes of ACP and HCA. Full article
(This article belongs to the Special Issue Spotlight on Bioactive Glasses and Their Related Composites)
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