Apatite-wollastonite Glass Ceramics Research Articles

Influence of Fe2O3 on synthesis, structure, hardness, and radiation shielding properties of Apatite–Wollastonite (AW) glass ceramics for bone implantation and shielding applications

This paper explores the important impact of Fe2O3 on the synthesis, structure, hardness, and radiation shielding characteristics of Apatite–Wollastonite (AW) glass ceramics for bone implantation and shielding application. The prepared studied samples were prepared and the effects of Fe2O3 addition on the synthesis process, density, and different physical and structural parameters comprehensively investigated. Additionally, the radiation shielding properties were determined by using PHITS simulation code and XCOM calculations for all samples. The results reveal that there is a significant impact of Fe2O3 addition on density, hardness, and radiation shielding of AW glass ceramics. The Vickers hardness values were calculated as 547, 598, and 621 Hv in measurements under 0.1 kg load., the density values are found to be as 2.87, 3.07 and 3.28 g/cm3 for AW, Aw -1Fe, and Aw -2Fe, respectively. The highest linear attenuation coefficient in the AW- 2Fe is 0.096 cm−1, Aw -1Fe showed 0.084 cm−1 and AW gave 0.072 cm−1 at 6 MeV. This study underscores the pivotal role of Fe2O3 as a multifaceted modifier in tailoring the properties of AW glass ceramics for bone implantation and other diverse applications extending from medical imaging to radiation and charged ions shielding.

Apatite–Wollastonite (AW) glass ceramic doped with B2O3: Synthesis, structure, SEM, hardness, XRD, and neutron/charged particle attenuation properties

In the study, the influence of doping apatite-wollastonite (AW) glass-ceramics (GCs) with B2O3 on the structural, physical, microstructural, and light and heavy particle interaction properties is presented. Using the solid-state reaction and the cold isostatic press method, pristine AW, 10 wt% (AW-B10), and 20 wt% (AW-B20) B2O3-doped AW GCs were prepared. The prepared GCs were subject to structural, chemical compositional, and surface morphological investigation through standard experimental processes. Furthermore, the neutron (fast and thermal) and charged radiation (electron, proton, alpha, and carbon ion) interactional parameters of the GCs were obtained through standard theoretical models and software. The density of AW (2.91 gcm−3) increases to about 2.957 and 2.986 gcm−3 as B2O3 increases to 10 and 20 wt%, respectively. The presence of boron oxide supported the wollastonite phase to remain glass and suppressed crystallisation in the AW GCs. Doping AW with B2O3 improved the interaction probabilities of the GCs with fast and thermal neutrons, electrons, protons, alpha particles, and carbon ions. B-rich AW is thus potentially useful as a target material in human tissues for boron neutron capture therapy for the management of cancer and tumours, isolating or shielding specific tissues in ion beam therapy processes, and other techniques that require the exposure of human tissues to irradiation.

Gamma attenuation, dose rate and exposure/absorption buildup factors of apatite–wollastonite (AW) ceramic system

Apatite-wollastonite (AW) is an important biomaterial useful in clinical practice for tissue engineering and other applications. In this research paper, AW and B2O3-doped AW glass ceramics (GCs) were reported and investigated deeply by means of their ability to attenuate gamma-photons. The studied samples denoted by AW, AW-10B, and AW-20B as the B2O3 content from 0 to 20 mol% with the step of 10. Using FLUKA and other theoretical approaches, photon interaction parameters for narrow and broad beam transmission through the AW GCs were estimated for the 15 keV–15 MeV energy range. Also, the density of the GCs increased as the B2O3 content increased. The mass attenuation coefficients were found to be within the ranges 0.0231–13.5659 cm2/g, 0.0225–12.3561 cm2/g, and 0.0220–11.1079 cm2/g for AW, AW-10B, and AW-20B, respectively. The effective atomic number of the GCs fell within the range 11.04–17.26, 10.88–17.01, and 10.21–16.72, respectively. As the doping concentration of B2O3 increased, the gamma energy that the AW GCs were able to absorb decreased. The addition of B2O3 compromised the photon shielding competence of AW in both narrow beam and broad beam scenarios. The GCs had better photon-absorbing competence than some existing gamma-photon shields. The GCs may thus be used as photon absorbers in clinical practice or in other nuclear applications.

Bioactive apatite-wollastonite glass ceramics coating on metallic titanium for biomedical applications: effect of boron.

Metallic titanium (Ti) implant surfaces need improvement for bioproperties and antibacterial behavior. For this purpose, a new boron-doped bioactive apatite-wollastonite (AW) coating was successfully developed on the Ti plate surface. The effects of boron addition on the microstructure, mechanical properties, and bioproperties of the AW coating were investigated. With the addition of boron (B), the AW coating morphology became less porous and compact. In terms of bio properties, the rate of apatite formation increased with the addition of B, and the cell viability rate increased from approximately 66-81%. B addition increased the elastic modulus of the AW coating from about 24-46GPa and increased its hardness about 2.5 times. In addition, while no antibacterial activity was observed in the AW coating, the addition of boron slightly introduced antibacterial properties. The novel AW/B composite coating obtained is promising for Ti implant surfaces.

An Investigation of In Vitro Bioactivities and Cytotoxicities of Spray Pyrolyzed Apatite Wollastonite Glass-Ceramics

An apatite-wollastonite glass ceramic (AWGC) has been recognized as one of the popular bioactive materials due to its good osteoconductivity and high mechanical properties in the field of tissue engineering. Various processes have been developed to fabricate AWGCs. Among them, the sol-gel process is one of the most popular processes. However, sol-gel has the drawbacks of discontinuous processing and long processing time, making it unsuitable for mass production. This study demonstrates a successful synthesis of AWGCs using a spray pyrolysis method to overcome these drawbacks, and the prepared pellets were sintered at temperatures of 700, 800, 900, 1000, and 1100 °C for four hours. In addition, X-ray diffraction, scanning electron microscopy, and X-ray energy-dispersive spectroscopy were used to obtain the phase composition, morphology, and chemical information of AWGCs. For bioactive measurements, among these AWGC samples, the 1100 °C sintered sample reveals the highest bioactivity. The MTT result indicates that all AWGCs are not non-toxic to the MC3T3-E1 cells and increase the growth rate of MC3T3-E1 cells.

Usability Of Three-dimensional Printing in Maxillofacial Surgery: A Narrative Review

Purpose: The three-dimensional (3D) printing method is a modern approach in which different custom designs are fabricated with high complexity according to the patient’s need. This narrative review aimed to highlight the materials used in 3D printers for medical use, especially in the field of oral and maxillofacial surgery. Methods: PubMed, Web of Sciences, and Google Scholar were searched for the relevant studies, and after meeting the inclusion criteria, articles were studied, and focused points were highlighted. Results: s: Synthetic and natural materials used in 3D printing include hydroxyapatite, tricalcium phosphate, bicalcium phosphate, apatite–wollastonite glass ceramics, stem cells, and collagen. The most frequent clinical applications include dental implants, maxillofacial trauma, facial cosmetics, orthognathic surgery, maxillofacial oncology, and maxillofacial reconstruction. Anatomical models and surgical instructions were the most often printed objects. The key benefits were increased surgical precision and a shorter operating time. The cost of the items, the length of the manufacturing process when printed by the industry, and legal concerns were the main drawbacks. Conclusion: The 3D models are beneficial for surgeons as they can save time and even human life. In the future, additional research should be done on the modeling, efficacy, and safety of natural materials, and systematic reviews and meta-analyses should be conducted for a better understanding.

Effect of apatite-wollastonite glass ceramics on the migration of mesenchymal stem cells

Event Abstract Back to Event Effect of apatite-wollastonite glass ceramics on the migration of mesenchymal stem cells Sylvia Muller1, Lindsey Nicholson1, Julian De Havilland1, Kenny Dalgarno1, Anne Dickinson1 and Xiao-Nong Wang1 1 Newcastle University, Institute of Cellular Medicine, United Kingdom Osteoarthritis is a progressive degenerative disease which results in the destruction of the bone and cartilage of the joints, primarily in the hands, hips and knees. Alterations in bone homeostasis leaves bones brittle and susceptible to damage while an increased production of enzymes reduces the structural integrity of the cartilage matrix, leaving it easily eroded. Apatite-wollastonite glass ceramic (A-W) is a biocompatible and osteoconductive material which can be formed into a tissue scaffold with the use of a 3D-printer. Osteogenic cells such as mesenchymal stem cells (MSCs) can be grown on these scaffolds in vitro and will undergo osteogenic differentiation. Additionally, resident MSCs in the areas surrounding the site of implantation may be able to migrate towards the scaffold to add to the bone formation. MSCs are traditionally isolated from sources such as the bone marrow by their adherence to plastic. The population this yields is often highly heterogeneous in phenotype and functional properties. Techniques for the enrichment of cell population based on marker expression have made it possible to generate a cell population with greater osteogenic potential. CD271+ MSCs, thought to be progenitor MSCs, have been shown to be osteogenicly primed and hence may be better suited for bone regeneration. This study compared the migrational potential of MSCs derived from plastic adherent cells (PA-MSCs) and MSCs derived from a population enriched for CD271highCD45- cells (CD271-MSCs). The aim of the work was to assess if A-W scaffold conditioned media could induce the migration of the two fractions of MSCs. This was done using cell or A-W scaffold conditioned media in a chemotaxis assay using multi-chambered slides and 18 hour time-lapse video microscopy. The known chemoattractant CXCL12 was used as a positive control and standard culture media was used as a negative control. Our results revealed that neither fraction of MSC had directed migration towards scaffold conditioned media. Additionally, A-W scaffold conditioned media was seen to inhibit MSC migration towards a known chemo-attractant. PA- and CD271-MSCs had similar patterns of migration towards the positive control CXCL12. PA-MSCs conditioned media was a strong chemo-attractant for PA-MSCs; however CD271-MSC conditioned media had little to effect on the migration of CD271-MSCs. Overall, this work has shown that A-W scaffolds may have an inhibitory affect on the potential of cells to migrate, which may have a negative impact on the overall quality of scaffold based regeneration. Additionally, the work suggests that the production of chemo-attractants from PA-MSCs and from CD271-MSCs is different. This work can help towards the greater understanding of MSC migration and homing. This work has been funded by Arthritis Reseach UK (ARUK) Keywords: Bone Regeneration, stem cell, Scaffold, Tissue Regeneration Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomaterials in mesenchymal and hematopoietic stem cell biology Citation: Muller S, Nicholson L, De Havilland J, Dalgarno K, Dickinson A and Wang X (2016). Effect of apatite-wollastonite glass ceramics on the migration of mesenchymal stem cells. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01525 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sylvia Muller Lindsey Nicholson Julian De Havilland Kenny Dalgarno Anne Dickinson Xiao-Nong Wang Google Sylvia Muller Lindsey Nicholson Julian De Havilland Kenny Dalgarno Anne Dickinson Xiao-Nong Wang Google Scholar Sylvia Muller Lindsey Nicholson Julian De Havilland Kenny Dalgarno Anne Dickinson Xiao-Nong Wang PubMed Sylvia Muller Lindsey Nicholson Julian De Havilland Kenny Dalgarno Anne Dickinson Xiao-Nong Wang Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Processing of Apatite-Wollastonite (AW) Glass-Ceramic for Three Dimensional Printing (3DP)

Apatite-wollastonite glass ceramics (AW) in bone regeneration and replacement applications have been seen as a favourable alternative to allografts and autografts. A-W has good biocompatibility, bioactivity, chemical stability and mechanical properties. In this study AW was used to fabricate 3D parts for bone applications by an indirect three dimensional printing (3DP) technique. Various powder blends of AW and maltodextrine (MD) were processed using the Z Corp 3D printing process, with two different liquid binder systems. The green parts were post-processed through using a heat treatment to burn off the binder and sinter the powder particles. Consistent results were obtained for all tested specimens in terms of density, porosity and shrinkage. The highest strength after sintering was 35.6 MPa.

Fabrication and Evaluation of Osteoblastic Differentiation of Human Mesenchymal Stem Cells on Novel CaO-SiO2-P2O5-B2O3Glass-Ceramics

Apatite-wollastonite glass-ceramics have high mechanical strength, and CaO-SiO2 -B2 O3 glass-ceramics showed excellent bioactivity and high biodegradability. A new type of CaO-SiO2 -P2 O5 -B2 O3 system of bioactive glass-ceramics (BGS-7) was fabricated, and the effect and usefulness was evaluated via bioactivity using simulated body fluid and human mesenchymal stem cells (hMSCs). The purpose of this study was to compare BGS-7 and hydroxyapatite (HA) using hMSCs in order to evaluate the bioactivity of BGS-7 and its possibility as a bone graft extender. Alkaline phosphatase (ALP) staining, ALP activity, cell proliferation 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay, Alizarin Red-S (AR-S) staining, calcium levels, the mRNA expression of ALP, osteocalcin, osteopontin, and runt-related transcription factor 2 (runx-2) using reverse-transcription polymerase chain reaction (RT-PCR) and the protein expression of osteocalcin and runx-2 using Western blot were measured by transplanting hMSC onto a tissue culture plate, HA, and BGS-7. The ALP staining and AR-S staining of BGS-7 was greater than that of HA and control. The ALP value of BGS-7 was significantly higher than that of HA and control. The MTS results showed that BGS-7 had a higher value than the groups transplanted onto HA and control on day 15. The calcium level was higher than the control in both HA and BGS-7, and was especially high in BGS-7. There were more mineral products on BGS-7 than on the HA when analyzed by scanning electron microscopy. The mRNA expression of ALP, osteopontin, osteocalcin, and runx-2 were higher on BGS-7 than on HA and the control when analyzed by RT-PCR. The relative gene expression of osteopontin and runx-2 were found to be higher on BGS-7 than on HA and the control by Western blot. Accordingly, it is predicted that BGS-7 would have high biocompatibility and good osteoconductivity, and presents a possibility as a new bone graft extender.

Tribological behavior of alumina-added apatite–wollastonite glass–ceramics in simulated body fluid

Tribological properties of an alumina-added apatite–wollastonite glass–ceramic produced by controlled heat treatment of a glass in the system MgO–CaO–SiO 2–P 2O 5–Al 2O 3 have been evaluated and compared with those of selected commercial dental ceramics, Duceragold and IPS Empress. Tribological tests were performed in dry condition and in simulated body fluid (SBF) using a pin-on-disk apparatus. The friction coefficient and specific wear rate of the tested materials were measured in dry and in artificial saliva (simulated body fluid: SBF) in order to elucidate the appropriateness of the alumina-added apatite–wollastonite (A–W) glass–ceramic for dental applications. Wear rate of the materials investigated varied from 0.96 × 10 −4 mm 3 N −1 m to 41.37 × 10 −4 mm 3 N −1 m depending on the bioenvironmental test conditions. The results of this study revealed that the alumina-added A–W glass–ceramic becomes more wear resistant as sintering temperature is increased and exhibits tribological properties similar to those of the commercial dental materials investigated.

Apatite wollastonite–poly methyl methacrylate bio-composites

Bio-composites consisting of sol–gel processed apatite wollastonite (AW) glass ceramics and poly methyl methacrylate (PMMA) were prepared by hot compaction method. Density of the composites decreased with increase in PMMA content, while, biaxial flexural strength (BFS) was 21 MPa for 20 wt.% PMMA and beyond which it decreased. A correlation between phase compositions of AW glass ceramics with BFS was attempted from the XRD results. In vitro bioactivity of the composites in a simulated body fluid (SBF) showed the formation of spherical globules on the surface within 7 days of soaking as observed by environmental SEM. Thin film XRD and EDX measurement confirmed these globules to be bone like apatite with Ca/P ratio 1.53 and FTIR measurement showed the corresponding peaks for phosphates. Results indicated the bone bonding ability of the composites by forming a surface apatite (calcium phosphate) layer in SBF and the growth increased with increase in soaking durations. ICP measurement of the remaining SBF after 7, 14 and 21 days soaking of samples was found to be in good agreement with the EDX analysis results.

Preparation and Properties of Magnetic Bioactive Glass-ceramics Doped with Mn-Zn Ferrite

Zn0.75Mn0.75Fe1.5O4 7.96×10 5 A·m 1 5.4�5.9A·m 2 ·kg 1 A-WGC A-W GC A-WGC Abstract: Novel magnetic bioactive glass-ceramics (MGC) in the system MgO-CaO-SiO2-P2O5-CaF2- MnO-ZnO-Fe2O3 were synthesized by doping Mn-Zn ferrite in apatite-wollastonite glass-ceramics (A- WGC). The effect of preparation methods on the magnetic performance and bioactivity of MGC was studied. The results show that apatite, wollastonite, flourapatite and Zn0.75Mn0.75Fe1.5O4 are the main phases of MGC. Under a magnetic field of 7.96×10 5 A·m −1 , the saturation magnetization of MGC fabricated by different ways ranges from 5.4A·m 2 ·kg −1 to 5.9A·m 2 ·kg −1 . Mn-Zn doping ferrite decreases the bioactivity of A-WGC. It takes at least 14d for a hydroxyapatite layer forming on the surface of MGC. Comparing with all the materials, the sample synthesized by mixing the heated A-WGC precursors with Mn-Zn ferrite precursor has proper magnetism and best bioactivity.

Development of Custom-Built Bone Scaffolds Using Mesenchymal Stem Cells and Apatite-Wollastonite Glass-Ceramics

There is a clinical need for new bone replacement materials that combine long implant life with complete integration and appropriate mechanical properties. We have used human mesenchymal stem cells (MSCs) to populate porous apatite-wollastonite (A-W) glass-ceramic scaffolds produced by the layer manufacturing technique, selective laser sintering, to create custom-built bone replacements. Confocal and scanning electron microscopy were used to determine optimal seeding densities and to demonstrate that MSCs adhered and retained viability on the surface of A-W scaffolds over a culture period of 21 days. We found a significant increase in the number of MSCs growing on the scaffolds over 7 days. Using bromodeoxyuridine incorporation we demonstrated that MSCs proliferated on the scaffolds. Using real-time PCR we analyzed the expression of the osteogenic markers alkaline phosphatase, collagen type-I, Cbfa-1, osteocalcin, osteonectin, and osteopontin by MSCs cultured in the absence of osteogenic supplements. The expression of the osteogenic markers by MSCs was equivalent to or significantly greater on A-W scaffolds than on tissue culture plastic. We also identified significantly higher alkaline phosphatase activity on A-W compared to a commercial calcium phosphate scaffold. These results indicate for the first time the biocompatibility and osteo-supportive capacity of A-W scaffolds and their potential as patient-specific bone replacement materials.

Porous Hydroxyapatite Scaffolds Coated With Bioactive Apatite–Wollastonite Glass–Ceramics

The objective of this study was to fabricate porous hydroxyapatite (HA) scaffolds coated with bioactive A/W glass–ceramics and to examine their mechanical and biological properties. Firstly, the HA scaffolds were prepared by the polymeric sponge replication method, and then A/W glasses were coated on the surface of the struts. All of the scaffolds had a highly porous structure with well‐interconnected pores. It was observed that the bioactive glass coating markedly increased the strength of the HA scaffolds. This enhancement was attributed to the formation of a dense and strong coating layer on the weak HA struts. The in vitro bioactivities of the scaffolds were markedly improved by the coatings. When the coated scaffolds were soaked in a simulated body fluid (SBF), the bone‐like apatite crystals were well mineralized on their surfaces. Osteoblast‐like cells (MC3T3) adhered, spread, and grew well on the porous scaffolds. The cells placed on the glass‐coated HA scaffold showed a higher proliferation rate and alkaline phosphatase (ALP) activity than those on the pure HA scaffold. These results demonstrate that the bioactive glass coating is effective in improving the strength and bioactivity of the porous HA scaffolds.

Apatite–wollastonite glass-ceramics part I Crystallization kinetics by differential thermal analysis

Apatite crystallization in the apatite–wollastonite glass exhibits a three-dimensional bulk mechanism with an Avrami parameter (n)≈3, while that of the second phase (wollastonite) shows a two-dimensional surface mechanism (planar growth) with n≈2. A strong effect of glass particle size on the wollastonite crystallization temperature is observed. The peak temperature is lower when the particle size is smaller.