materials Bioactive Glass and Glass-Ceramic Scaffolds for Bone Tissue Engineering (original) (raw)
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Bioactive glass scaffolds for bone regeneration and their hierarchical characterisation
Proceedings of the …, 2010
Scaffolds are needed that can act as temporary templates for bone regeneration and actively stimulate vascularized bone growth so that bone grafting is no longer necessary. To achieve this, the scaffold must have a suitable interconnected pore network and be made of an osteogenic material. Bioactive glass is an ideal material because it rapidly bonds to bone and degrades over time, releasing soluble silica and calcium ions that are thought to stimulate osteoprogenitor cells. Melt-derived bioactive glasses, such as the original BioglassH composition, are available commercially, but porous scaffolds have been difficult to produce because Bioglass and similar compositions crystallize on sintering. Sol-gel foam scaffolds have been developed that avoid this problem. They have a hierarchical pore structure comprising interconnected macropores, with interconnect diameters in excess of the 100 mm that is thought to be needed for vascularized bone ingrowth, and an inherent nanoporosity of interconnected mesopores (2-50 nm) which is beneficial for the attachment of osteoprogenitor cells. They also have a compressive strength in the range of cancellous bone. This paper describes the optimized sol-gel foaming process and illustrates the importance of optimizing the hierarchical structure from the atomic through nano, to the macro scale with respect to biological response.
Current advances in bone tissue engineering concerning ceramic and bioglass scaffolds: A review
Ceramics International, 2019
Life expectancy has been growing, and more people are developing bone diseases such as arthritis and osteoporosis. Degenerative pathologies, injuries, and trauma can damage the bone tissues, requiring treatments that facilitate its repair, replacement, or regeneration. In this context, many materials have been developed to match this demand. Bioglasses and ceramics are promising inorganic materials to produce scaffolds for bone regeneration due to their attractive properties, such as biocompatibility, osteoinduction, and osteoconduction, besides their similarity with bone composition. Although their established advantages, these materials present limitations such as inadequate mechanical properties and fast degradation rate. Research work has been widely carried out to develop bioglasses, silicate, and phosphate calcium ceramics scaffolds with appropriated properties to enlarge their applications in bioengineering. Different fabrication techniques have also been evaluated. Incorporating other materials or particles, such as polymers, oxides and metal particles into the scaffolds has shown beneficial effects in mechanical strength and bone production stimulation. In this review, we provide an overview concerning the recent advances in developing calcium phosphates, calcium silicates, bioglasses, and composites scaffolds for bone regeneration in medical and dental applications.
Evaluation Nanostructure Properties of Bioactive Glass Scaffolds for Bone Tissue Engineering
Advanced Materials Research, 2013
The use of biomaterials in bone tissue engineering newly has been developed. They are biocompatible material which are reabsorbed in body and replaced with newly formed tissue. Bioactive glass scaffolds will be appropriate candidates if pore morphology, size and structures are controlled. Scaffolds with nanostructure will provide these goals. In this research bioglass powder was synthesized with sol-gel method to achieve nanostructure powder. The glass powder was characterized with transmission electron microscope (TEM). Scaffolds were prepared with combination of bioglass powder and sugar as porogen followed by pressing at 80 MPa then sintering at 1050 ºC. The morphology of sintered scaffolds was characterized with scanning electron microscope (SEM) and porosity was measured with density method. Mechanical properties were assessed with compressive strength. The TEM results show that synthesized powder has particle size about 25 nm. The SEM results show that nanopores and macropores are connectively distributed in whole part of scaffolds. The compressive strength of scaffolds was 0.8 MPa. Overall, the scaffold is suggested that is appropriate alternative for bone tissue engineering.
45S5 Bioglass®-derived glass–ceramic scaffolds for bone tissue engineering
Biomaterials, 2006
Three-dimensional (3D), highly porous, mechanically competent, bioactive and biodegradable scaffolds have been fabricated for the first time by the replication technique using 45S5 Bioglass s powder. Under an optimum sintering condition (1000 1C/1 h), nearly full densification of the foam struts occurred and fine crystals of Na 2 Ca 2 Si 3 O 9 formed, which conferred the scaffolds the highest possible compressive and flexural strength for this foam structure. Important findings are that the mechanically strong crystalline phase Na 2 Ca 2 Si 3 O 9 can transform into an amorphous calcium phosphate phase after immersion in simulated body fluid for 28 days, and that the transformation kinetics can be tailored through controlling the crystallinity of the sintered 45S5 Bioglass s . Therefore, the goal of an ideal scaffold that provides good mechanical support temporarily while maintaining bioactivity, and that can biodegrade at later stages at a tailorable rate is achievable with the developed Bioglass s -based scaffolds. r
2006
Bioactive glasses and glass-ceramics were made from the system Na2O-CaO-SiO2-P2O5 by the melt quench method. The optimal conditions for heat and chemical treatments were determined. The effects of the heat and chemical treatments on the structure of the glasses and glass-ceramics were investigated using optical microscopy. Heat treatments of nine hours produced a higher degree of crystallization and larger crystals than heat treatments of three and six hours. The samples from batch 45S exhibited greater crystallization than the other samples tested. 1.0M HCl for the chemical treatment was found to be superior to 0.3M and 3.0M HCl because the 1.0M acid produced the highest pore density and the most uniform structure. One hour and 85°C were determined to be the best time and temperature, respectively, for the chemical treatment because they resulted in the highest porosity and most even structure compared to temperatures of 70°C and times of two hours. Overall, the six hour heat treat...
45S5 Bioglass s -derived glass–ceramic scaffolds for bone tissue engineering
Three-dimensional (3D), highly porous, mechanically competent, bioactive and biodegradable scaffolds have been fabricated for the first time by the replication technique using 45S5 Bioglass s powder. Under an optimum sintering condition (1000 1C/1 h), nearly full densification of the foam struts occurred and fine crystals of Na 2 Ca 2 Si 3 O 9 formed, which conferred the scaffolds the highest possible compressive and flexural strength for this foam structure. Important findings are that the mechanically strong crystalline phase Na 2 Ca 2 Si 3 O 9 can transform into an amorphous calcium phosphate phase after immersion in simulated body fluid for 28 days, and that the transformation kinetics can be tailored through controlling the crystallinity of the sintered 45S5 Bioglass s. Therefore, the goal of an ideal scaffold that provides good mechanical support temporarily while maintaining bioactivity, and that can biodegrade at later stages at a tailorable rate is achievable with the developed Bioglass s-based scaffolds.
Glass–ceramic scaffolds for tissue engineering
Advances in Applied Ceramics, 2008
This paper is a critical discussing key on previous results of the authors in the field of glassceramic scaffolds for tissue engineering. With the aim of developing biological substitutes that restore, maintain or improve tissue functionality, glass-ceramic scaffolds were produced starting from a glass system composition enriched with traces of specific elements. The presence of one or more specific ions can modulate the better environmental conditions to favour the growth of specific specialised cells, a necessary prerequisite to originate different kinds of tissues. The main predictable use is for bone reconstruction, but other possible uses are expectable for some specific tissues (cartilage, nerve, tendons, etc.). In order to obtain the best initial tissue integration, a decisive role is played by porosity of the glass scaffold. The glass structure can generally be resorbed, leaving its volume available for tissue nodules which grow and assemble together, producing an equal volume of tissue. In bone, the action is synergically increased thanks to the phenomena of bone conduction and bone induction of the proposed porous bioactive ceramics. On the other hand, glass-ceramic scaffolds have already been appreciated as a superior material for bone healing. Compared to similar hydroxyapatite structures, the glassceramic ones exhibit a greater starting mechanical resistance (useful for surgical manipulations) and differently from the hydroxyapatite ones, they are resorbed more easily in time. This is a good requisite for a material to be used in bone tissue engineering. The ceramic bioactive systems can be used both in bulk and as coatings.
Acta Biomaterialia, 2007
Glass-ceramic macroporous scaffolds for tissue engineering have been developed using a polyurethane sponge template and bioactive glass powders. The starting glass (CEL2) belongs to the system SiO 2 -P 2 O 5 -CaO-MgO-Na 2 O-K 2 O and has been synthesised by a conventional melting-quenching route. A slurry of CEL2 powder, polyvinyl alcohol and water has been prepared in order to coat, by impregnation, the polymeric template. An optimised thermal treatment was then use to remove the sponge and to sinter the glass powders, leading to a glass-ceramic replica of the template. Morphological observations, image analyses, mechanical tests and in vitro tests showed that the obtained devices are good candidates as scaffolds for bone-tissue engineering, in terms of pore-size distribution, pore interconnection, surface roughness, and both bioactivity and biocompatibility. In particular, a human osteoblast cell line (MG-63) seeded onto the scaffold after a standardised preconditioning route in simulated body fluid showed a high degree of cell proliferation and a good ability to produce calcium nodules. The obtained results were enhanced by the addition of bone morphogenetic proteins after cell seeding.
Tissue Engineering Scaffolds from Bioactive Glass and Composite Materials
B one tissue engineering combines cells and a biodegradable 3D scaffold to repair diseased or damaged bone tissue. Challenges are set by the design and fabrication of the synthetic tissue scaffold and the engineering of tissue constructs in vitro and in vivo. In bone tissue engineering, bioactive glasses and related bioactive composite materials represent promising scaffolding materials. In this chapter, we present state-of-the-art fabrication technologies for a variety of bone tissue engineering scaffolds discussing their microstructure and relevant properties. The focus is in the development of synthetic scaffolds based on bioactive glasses and their polymeric composites, including 45S5 Bioglass®, Bioglass®-poly(lactic acid) and Bioglass®-poly(hydroxylalkanoate) composites. Our group has recently developed further a number of scaffold fabrication techniques, including foam replication technique, thermally induced phase separation, textile and foam coating methods and biomimetic approaches to optimise scaffold structure and properties. Among these techniques, the foam replication method to produce highly porous, biodegradable and mechanically competent Bioglass®-derived glass-ceramic scaffolds is highlighted as one of the most promising technologies because of its potential in addressing basic scaffold requirements as well as the vascularisation issue. The enhancement of scaffold properties and functions by surface modification of the basic pore network, both its chemistry and topography, is also discussed. Finally, limitations of presently developed bone tissue constructs are summarized and future directions of research are discussed.
Journal of Biomedical Materials Research Part A, 2008
Cell support function as well as cell proliferation on highly porous Bioglass 1 -derived glass-ceramic scaffolds (designed for bone tissue engineering) have been assessed in vitro using osteoblast-like cells (MG 63) cultured for up to 6 days. The biodegradation and mechanical stability of the scaffolds in the cell-culture medium have also been investigated. It was found that the scaffolds had excellent cell supporting ability, with cells effectively infiltrating into and surviving at the center of the scaffolds. A quantitative study using the AlamarBlue TM assay revealed that the proliferation of cells on the glass-ceramic materials was comparable to that on the noncrystallized Bioglass 1 . While the crystalline phase in the glass-ceramic scaffolds transformed into a biodegradable amorphous calcium phosphate phase during cell culture, the mechanical strength of the scaffolds was maintained when compared with that of scaffolds incubated in simulated body fluid or immersed in cell-free culture medium. It is believed that the attached cells and collagen secreted by cells could fill the micropores and microcracks on the surface of the foam struts, thus contributing to the mechanical stability of the degrading scaffolds. In summary, the developed glass-ceramic scaffolds possess the most essential features of a scaffold for bone tissue engineering: they are capable to support and foster relevant cells, able to provide temporary mechanical function, and biodegradable.