Behaviour Of Bioactive Glasses Research Articles

Influence of Strontium on the Biological Behavior of Bioactive Glasses for Bone Regeneration.

Bioactive glasses (BGs) can potentially be applied in biomedicine, mainly for bone repair and replacement, given their unique ability to connect to natural bone tissue and stimulate bone regeneration. Since their discovery, several glass compositions have been developed to improve the properties and clinical abilities of traditional bioactive glass. Different inorganic ions, such as strontium (Sr2+), have been incorporated in BG due to their ability to perform therapeutic functions. Sr2+ has been gaining prominence due to its ability to stimulate osteogenesis, providing an appropriate environment to improve bone regeneration, in addition to its antibacterial potential. However, as there are still points in the literature that are not well consolidated, such as the influence of ionic concentrations and the BG production technique, this review aims to collect information on the state of the art of the biological behavior of BGs containing Sr2+. It also aims to gather data on different types of BGs doped with different concentrations of Sr2+, and to highlight the manufacturing techniques used in order to analyze the influence of the incorporation of this ion for bone regeneration purposes.

Impact of solution pH (5–9) and dissolution products on in vitro behaviour of the bioactive glass S53P4

The impact of dissolution products on the reaction behaviour of bioactive glasses was explored. Bioactive glass S53P4 particles were immersed in solutions with initial pH of 5–9. After 24 and 72 h, the solution extracts were used for testing unreacted particles. The pH, ion concentrations, and glass surfaces were analysed as functions of immersion time. More Ca, Na, and P dissolved at lower pH (5) than at higher pH (7.4 or 9). The dissolution changed from an incongruent to an apparent congruent with increasing pH. Dissolution products in extracts changed the reaction layer structure on glass particles and led to lower ion release at pH 7.4 and 9. Dissolution increased almost linearly with time in acidic solutions. Silica-rich layer and calcium phosphate were identified on the particles after immersion in all solutions except at pH 9. Local ion concentration variations affected dissolution, leading to nonuniform ion release rates.

Issue Information

International Journal of Applied Glass ScienceVolume 14, Issue 3 p. 339-340 ISSUE INFORMATIONFree Access Issue Information First published: 31 May 2023 https://doi.org/10.1111/ijag.16588AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Cover Photograph: The United Nations' declaration making 2022 the International Year of Glass has allowed the global glass community to celebrate the wonders of this amazing material. This special issue of IJAGS looks forward to the future, and the cover displays the many facets and applicability of glass. From curved crystal lattices (upper left; Musterman) to Corning's production of industrial glass (next image counterclockwise; Kohli) to MD simulations of polymer blends (bottom image; Habasaki), the research field is wide and varied. The bottom-right image shows glass-ceramics (Qi), while the next image counterclockwise illustrates darkening in fiber glasses (Chongyun). Finally, the top image displays the behavior of bioactive glasses with zinc. Taken as a whole, the articles in this issue highlight the breadth of our field and the continuing promise of glass as a material unparalleled in human history. Volume14, Issue3July 2023Pages 339-340 RelatedInformation

The effects of boron trioxide on the structure and degradation behaviour of borosilicate bioactive glass

ABSTRACT Degradation behaviour of bioactive glass (bioglass) is one of the most important factors affecting bone repair, because an excellent and controllable degradation rate can match the rate of new bone formation. In this research, the derived borosilicate bioglasses based on the 6Na2O-8K2O-8MgO-22CaO-18B2O3-54SiO2-2P2O5 component were synthesized. The effects of B2O3 on the structure, degradation behaviour and cytocompatibility of borosilicate bioglasses were systematically studied. The results showed that with B2O3 addition, the network-forming units became diversified and part of BO4 units transformed into BO3 units. These factors weakened the chemical durability of borosilicate bioglass, thus accelerating the bioglass shedding and altering the ions release, especially B. This study provides a theoretical basis for designing borosilicate bioglass with adjustable degradation rate and ion release behaviour to meet the diverse needs of clinical bone repair.

Thermodynamic behavior of bioactive glass in relationship with high fluorine content

Fluoride (F) is important for enhancing illogical activity of bioceramics. To increase fluoride content of derived Hench bioactive glass (BaG), bioactive fluorosilicate glasses (BaG-Fx) were synthesized by using melting method and characterized using different physico-chemical analyses. Fluoride-containing BaGs were synthesized at a temperature of 1350°C. Structural and thermal effect of calcium fluoride (CaF2) insertion into the glass network in the BaG: SiO2–CaO–Na2O–P2O5 quaternary system was studied. Indeed, the incorporated amounts of fluorine (CaF2) (from 5% to 20% by mass) induced significant physico-chemical changes. Through the structural study by X-ray diffraction (XRD), the amorphous character of our fluorosilicate glasses is proven. Infrared (IR) spectroscopy proved the incorporation of fluorine into the glass matrix. In the microstructural framework, we revealed the morphological changes of the glass powders as a function of the CaF2 content. These results were confirmed by Brunauer, Emmett and Teller (BET) measurements. Through Differential Scanning Calorimetry (DSC) thermal analysis we established the impact of fluoride ions on the structural dynamics and thermodynamic properties of these newly developed bioactive glasses. Accordingly, it was possible for the first time to incorporate as much as 20 wt% of CaF2 in BaG respecting the conditions of bioactivity and biodegradability required by Hench. After detailed analyses of the transformation entropies of BG-Fx as a function of the added CaF2 content, it can be stated that the intermolecular movements within the fluorosilicate network are more limited as a function of the added CaF2 amount. This slows down the ion exchange phenomena and subsequently the dissociation of the material in vitro, which can be anticipated to occur after implantation in vivo.

Impact of fluid flow rate on the dissolution behavior of bioactive glass S53P4

Bioactive glasses have proven to be effective grafting materials for the repair of bone tissue defects. However, accurately predicting the degradation behavior of bioactive glasses in vivo remains challenging.The present study examines the effect of flow rate on the dissolution behavior of bioactive glass S53P4 in plain Tris buffer and Tris-buffered simulated body fluid. Ion concentrations, pH changes, and alteration layer development at the glass surface were studied over 24 h for the three different flow rates studied. The study revealed significant flow rate dependent differences in the glass dissolution rate, ion release, and reaction layer development. At the lowest flow rate, 0.04 ml min−1, highly incongruent dissolution and formation of diffusion-limiting reaction layers were identified. At the medium flow rate, 0.2 ml min−1, the dissolution rate was sensitive to solution saturation state effects. At the highest flow rate, 0.6 ml min−1, dissolution became more surface-controlled and was nearly congruent. The findings support the idea that bioactive glass dissolution can be described by a combination of diffusion barrier and chemical affinity concepts. In demonstrating the impact of flow rate on bioactive glass dissolution, the study underscores the importance of performing dynamic in addition to static dissolution tests.

Quasi-static compressive behavior of bioactive glass reinforced high density polyethylene composites

Compressive behavior of additively manufactured bioactive glass (BAG) reinforced high density polyethylene (HDPE) composites under quasi static conditions (0.001, 0.01 and 0.1 s−1 strain rates) is investigated in this work. HDPE feedstock filaments with 5, 10 and 20 wt% of bioactive glass are extruded for fused filament fabrication (FFF) based 3D printing (3DP). Compressive properties are extracted from the stress–strain plots. Elastic modulus and yield strength of the samples increase with filler addition and strain rate. Energy absorption increases with increase in strain rate and BAG content. All the samples exhibit homogeneous ductile deformation with distinct barrelling effect without any visible cracks. Deformation and energy absorption behavior of the tested samples are investigated using micrography.

Evaluation of Vertical Guided Bone Regeneration Using a Particulate Form of Experimental Bioactive Glass in a Rabbit: A Case Report with Literature Review

Background: There are a large number of different types of bone-grafting materials that are used for the regeneration of atrophied alveolar ridges in order to make dental implantation possible. However, available surgical techniques and materials for bone augmentation do not contribute to the achievement of the desired reliable results and require a search for new solutions to an existing problem. A group of synthetic osteoplastic materials based on bioactive glass (BAG) may become a matter of choice in bone tissue regeneration because of special osteogenic properties. The aim of this study was to visually and histologically evaluate the behavior of an experimental BAG in rabbit tibia bone samples, which were collected from the animal 6 weeks after filling the bone defects. Methods and Results: The observation was carried out on one outbred rabbit whose tibia bone defects were filled with an experimental osteoplastic material based on the BAG. The chemical composition of the experimental osteoplastic material included SiO2 (41%), Na2O (21%), CaO (28.5%), P2O5 (6%), CaF2 (1.5%), MgO (1%), Al2O3 (1%). For histological analysis, H&E staining of paraffin-embedded tissues was performed according to the standard technique. Light microscopy of tissue samples was performed using a Leitz HM-LUX microscope (Germany). Six weeks after filling the bone defects, a strong bond between the augmented hard tissue and rabbit tibia was recognized. Also, a dense fusion of adjacent soft tissues with a newly formed bone without signs of chronic inflammation or graft particles in granular tissue was noted. Microscopic examination of the stained sections showed the presence of mature viable BT with a uniform distribution of osteocytes. Also, residual fragments of the degraded biomaterial surrounded by the fibers of a woven bone were revealed in several slices. Conclusion: In accordance with the results of this experiment, it can be concluded that the usage of BAG related to the system SiO2(41%)-Na2O(21%)-CaO(28.5%)-P2O5(6%)-CaF2(1.5%)-MgO(1%)-Al2O3(1%) may increase the volume of bone without application of barrier membrane. However, further research involving more animals needs to be done to estimate the scientific significance of the obtained data and to evaluate the mechanical properties of augmented bone.

Photothermally active borosilicate-based composite bone cement for near-infrared light controlled mineralisation

ABSTRACT The mineralisation and ion release behaviour of the bioactive glasses play a crucial role for their biomedical applications. It is, however, difficult to control these processes artificially in situ. Herein we utilised NIR radiation as an external stimuli to tailor these processes to match specific requirements. Therefore, the composite bone cements based on borosilicate glass incorporated with TiN NPs were fabricated. It is found that, under 1064 nm laser irradiation, the composite bone cements exhibited remarkable photothermal performance and the cumulative amount of silicon, boron and calcium ions of the composite bone cement increased by 4.74, 1.79, and 1.26 times within 10 days, respectively. Even at the later stage of mineralisation, the ions release rates could be accelerated. Additionally, 1064 nm laser irradiation accelerated the formation of HA. Therefore, this paper provided an effective way to regulate the mineralisation and ion release behaviour of bioactive glass after implantation.

Role of magnesium and aluminum substitution on the structural properties and bioactivity of bioglasses synthesized from biogenic silica

The objective of this study was to investigate the effect of magnesium (1 wt%) and aluminum (1 wt%) incorporation on the in vitro bioactivity and biodegradation behavior of 45S5 bioactive glasses synthesized from rice husk biogenic silica. The performance of biogenic silica-based samples was compared well with commercial silica-based counterparts. The in vitro biodegradation behavior of bioactive glasses was evaluated by the weight loss of samples and pH variation in the Tris buffer solution. Based on composition, bioglasses possessed different properties before and after simulated body fluid (SBF) immersion. The incorporation of magnesium (Mg) and aluminum (Al) enhanced the Vickers hardness of bioglasses. All the bioglasses showed the hydroxyapatite layer formation after SBF treatment as confirmed by the dissolution, FTIR, SEM and XRD analysis, however it was more prominent in the rice husk silica-based 45S5 bioglass. The biogenic silica seems to be a promising starting material for bioglass systems to be used in bone tissue engineering applications.

Network structure and thermal properties of bioactive (SiO2\u2013CaO\u2013Na2O\u2013P2O5) glasses

Ca- and P-based bioactive glasses are excellent candidates for design and manufacture of biomaterials. Understanding the structure and physico-chemical–thermal behaviour of bioactive glasses is a fundamental step towards the design of a new generation of biocompatible materials. In this study, the structure of SiO2–CaO–Na2O glasses and its derivatives, obtained by substituting Na2O with P2O5 and prepared by melt–quench technique, was studied with neutron and electron diffraction techniques combined with thermal analysis, high-resolution electron microscopy and X-ray photoelectron spectroscopy. Neutron and electron diffraction data were analysed with reverse Monte Carlo simulation and pair distribution function analysis, respectively. Bioactivity of P2O5 substituted glasses was also investigated and proven in vitro using simulated body fluid. Based on the structural analysis, it was found that Si and P atoms are in well-defined tetrahedral units with a bond distance of 1.60 Å for both Si–O and P–O bonds, although P exhibits a higher average coordination number than Si. With increasing phosphate content, tendentious changes in the glass behaviour were observed. Linear increase in Tg, supported by the changes in the average coordination numbers of Si and P, indicates strengthening of network structure with increasing P content and formation of P–O–Ca atomic linkages, which lead to Ca–P-rich atomic environments in the silicate network. These Ca–P-rich environments trap volatile elements and thus decrease the total weight loss during heating at higher P concentrations. In the case of the highest investigated P2O5 content (5 mol%), nanoscale structural inhomogeneity and the formation of Ca–P-rich clusters were also revealed by electron diffraction and atomic resolution imaging. This type of Ca–(Na)–P clustering has a key role in the behaviour of phosphate-substituted silicate glasses under physiological conditions.

Comparison of Zn and Sr effects on thermal properties and on the excess entropy of doped glasses for use in the biomedical field

This research is based on the study of thermal behaviour of bioactive glass in the quaternary system SiO2-CaO-Na2O-P2O5 doped with metallic elements such as Zn and Sr destined for use as bone biomaterial. It encompasses glass transition temperature, crystallization temperature and melting temperature. This work is based on both determination and comparison of the effects of Zn and Sr on thermal characteristics after their introduction in the glass matrix. Thermal stability and excess entropy of all studied glasses have been calculated. Obtained results highlight the different effects of doping on the glasses thermal behaviour. Most notable effects are the sharp decrease of melting temperature of 10 wt% Zn-doped glass and the increase of crystallization temperature of 10 wt% Sr-doped glass. Furthermore, excess entropy of pure glass increases with addition of Sr and decreases with addition of Zn.

Understanding the structural drivers governing glass-water interactions in borosilicate based model bioactive glasses.

Realizing the goal of designing third generation bioactive glasses requires a thorough understanding of the complex sequence of reactions that control their rate of degradation (in physiological fluids) and the structural drivers that control them. In this article, we have highlighted some major experimental challenges and choices that need to be carefully navigated in order to unearth the mechanisms governing the chemical dissolution behavior of borosilicate based bioactive glasses. The proposed experimental approach allows us to gain a new level of conceptual understanding about the composition-structure-property relationships in these glass systems, which can be applied to attain a significant leap in designing borosilicate based bioactive glasses with controlled dissolution rates tailored for specific patient and disease states.

A thermodynamic discourse on the dissolution behavior of bioactive glasses

AbstractThe interaction between bioactive glass and body fluid is crucial for the special properties of this material, therefore a large number of experimental data is available in literature. However, a frame for systematic interpretation of these results in terms of understanding the mechanisms at the interface between glass and body medium and the relation between glass composition and dissolution behavior is still missing. For two multicomponent bioactive glasses, 45S5 and 13-93, the Gibbs energies of the glassy material on one side and their aqueous system on the other side were calculated individually. The difference between solid material and aqueous system further constitutes the pH dependent Gibbs energy of hydration, ∆Ghydr. The impact of glass compositions and glassy or crystalline state on ∆Ghydr is demonstrated referring to chemical durability. Along considerations regarding the aqueous system, the thermodynamic calculations proof the precipitation of hydroxyapatite inwater and simulated body fluid for a systemcontaining P2O5 and Ca2+. In the course of deriving the Gibbs energies for bioactive glass compositions via constitutional compounds, bioactive behavior is discussed from the point of coexisting equilibrium phases in the system of Na2O-CaO-SiO2.

Biological behavior of bioactive glasses and their composites

This review summarizes current developments in improving the biological behavior of bioactive glasse and their composites.

Realistic Models of Bioactive Glass Radioisotope Vectors in Practical Conditions: Structural Effects of Ion Exchange

Yttrium-doped silicate glasses with bioactive properties (YBGs) have potential applications in radiotherapy. The effect of gradual release of sodium and calcium from a YBG composition, modeling the ion-exchange processes occurring upon contact with an aqueous biological medium, was investigated through molecular dynamics simulations. The ion-exchanged hydroxylated structures exhibit some important differences with respect to the pristine dry composition, such as increased cross-linking and yttrium clustering, whose potential effects on their performances as radioisotope vectors are discussed. These findings also highlight the importance of taking into account the structural effects of ion exchange with an aqueous environment in order to develop more realistic predictive models of the behavior of bioactive glasses and related materials in practical conditions.

Stereolithographic Ceramic Manufacturing of High Strength Bioactive Glass

Bioactive glasses and glass ceramics like the 45S5 formulation have been studied toward biocompatibility and biodegradability for years. Nevertheless, clinical applications as bone substitute or scaffold material are highly limited because of the often poor mechanical behavior of bioactive glasses. In this study, we are able to provide a new production alternative for 45S5 bioactive glass structures resulting in parts with high density and strength. Using the stereolithographic ceramic manufacturing (SLCM) process, it is possible to additively produce solid bulk glass ceramics as well as delicate scaffold structures. Recent developments in SLCM slurry preparation together with an appropriate selection of raw materials led to 3D parts with a very homogeneous microstructure and a density of about 2.7 g/cm³. Due to the low number and small size of defects, a high biaxial bending strength of 124 MPa was achieved. Weibull distribution also underlines good process control showing a Weibull modulus of 8.6 and a characteristic strength of 131 MPa for the samples tested here. By reaching bending strength values of natural cortical bone, bioactive glasses processed with SLCM could eventually advance to be an interesting bone substitute material even in load‐bearing applications, valuing the huge efforts undertaken to understand their bioactive behavior.

T–T–T behaviour of bioactive glasses 1–98 and 13–93

Abstract In this work crystallization kinetics of bioactive glasses 1–98 and 13–93 are discussed. Within a certain temperature–time window these glasses can be hot worked into various products without interfering with crystallization. The crystallization was studied isothermally by heating glass plates at different temperatures for different times. Phases in the samples were studied through XRD and SEM analyses. The nucleation-like curves and crystallization characteristics were measured with DTA. The temperature of maximum nucleation was measured for glass 1–98 at 725 °C and for 13–93 at 700 °C. The activation energy of crystallization of both glasses was 280 kJ/mol. The Johnson–Mehl–Avrami exponent and the SEM micrographs of the samples suggested surface crystallization. The primary crystalline phase was wollastonite. The growth rate of the crystallized surface layer was 1 order of magnitude higher in the plates of 1–98 than in 13–93. The results can be utilized to optimize the parameters in hot-working of the glasses.

Double layered nanostructured composite coatings with bioactive silicate glass and polymethylmetacrylate for biomimetic implant applications

We studied the corrosion behaviour of bioactive glass–polymer nanostructured coatings of titanium implants for prostheses. The layers were deposited by MAPLE on titanium substrates of biomedical use. The potentiodynamic polarization investigations showed that the obtained samples exhibited a higher corrosion resistance as compared to bare titanium. The behaviour of coatings in contact with physiological fluids was studied in vitro by electrochemical impedance spectroscopy. The initial bioactive glass–polymer coating proved to be a good insulator. After immersion in simulated body fluid the bioactive glass dissolution and the adsorption of electrolyte ions were initiated causing the formation of an outer bioapatite protective layer. A simple cell circuit proved sufficient to describe unimmersed, short (7 days) and/or long (42 days) time immersed samples at room temperature, while after 14, 21, 28 or 35 immersion days, the use of a double cell circuit was mandatory. This was indicative for the formation of a double nanostructure consisting of an inner barrier (mainly polymer) and an outer porous (bioapatite) film with potential beneficial effects for osseointegration capacity of the Ti implants.

In vitro bioactivity and crystallization behavior of bioactive glass in the system SiO2-CaO-Al2O3-P2O5-Na2O-MgO-CaF2

AbstractIn this study, bioactivity of glass in the system SiO2-CaO-Al2O3-P2O5-Na2O-MgO-CaF2 was investigated. For this purpose, a glass sample was prepared by the traditional melting method. Crystallization behavior of bioactive glass was also investigated using differential thermal analyses. The Avrami constant of bioactive glass sample calculated according to the Ozawa equation was 3.72 ± 0.4, which indicates bulk crystallization. Using the Matusita-Sakka and the Kissinger equations, activation energy of crystal growth was determined as (394 ± 17) kJ mol−1 and (373 ± 12) kJ mol−1, respectively. These results indicate that the crystallization activation energy data of bioactive glass obtained in this study are accurate and reliable. Bioactivity of the resultant glass sample was analyzed by immersion in simulated body fluid. Scanning electron microscopy, thin film X-ray diffraction, ultraviolet spectroscopy and inductively coupled plasma techniques were used to monitor changes in the glass surface and the simulated body fluid composition. The results revealed that a hydroxyapatite layer was formed on the glass surface after 21 days of immersion in SBF. Formation of the hydroxyapatite layer confirmed the bioactivity of the glass in the system SiO2-CaO-Al2O3-P2O5-Na2O-MgO-CaF2. In addition, physical and mechanical properties of the sample were measured to determine changes in the properties with the immersion time. The results show that bioactive glass maintained its strength during the immersion in a simulated body fluid solution.