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In this study, a simple and facile strategy was developed for the synthesis of novel hydroxyapatite (HA)/nanostructured monticellite ceramic composites by mechanical method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDS) were used to peruse the phase structure, and morphology of soaked ceramic composites in simulated body fluid (SBF). The in vitro bioactivity of HA-based ceramic composites with nanostructured monticellite ranging from 0 to 50 wt% was evaluated via investigating the formation ability of bone-like calcium phosphates in SBF and the effect of obtained extracts from composites dissolution on osteoblast-like G-292 cell line. Moreover, In vitro cytocompatibility of the HA/monticellite ceramic composites was investigated by MTT, cell growth & adhesion and alkaline phosphatase (ALP) activity assays, and quantitative real-time PCR analysis. The results showed that HA/nanostructured monticellite ceramic composites could induce apatite formation in SBF. The cell proliferation and growth exposed to ceramic composites extracts were significantly stimulated and promoted at a certain concentration range compared to control for various time periods of cell culture. The optimized composite extract enhanced considerably gene expression of G-292 type X collagen (COLX) at different days. Also, G-292 cells were spread and adhered well on the ceramic composite disc. Furthermore, ALP activity of G-292 cells exposed to ceramic composites extracts was dramatically enhanced in comparison with pure HA extract (as control) at different concentrations for various time periods of cell culture. The results suggest that the optimized HA/nanostructured monticellite composite is promising biomaterial for clinical applications such as orthopedic and dentistry., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This study focuses on the effect of Sr-, F-, and their co-doping on the structure, biodegradation, bioactivity and cytocompatibility of diopside-based scaffolds, using X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, Archimedes densitometry, inductively coupled plasma spectroscopy, pH-metry, and cell MTT assay. The structural characterization of the scaffolds confirmed the successful incorporation of the dopants into the ceramic. In addition, all the doped scaffolds presented higher apatite-forming ability levels in comparison to the undoped one, where the highest and the least impact of doping on bioactivity belonged to F- and co-doping, respectively. It was found that the biodegradation difference of the scaffolds in terms of principal ions and the chance of F-incorporation into precipitated apatite determine the bioactivity difference of the samples. Osteoblast-like MG-63 cells exhibited the highest and lowest compatibility to the Sr-doped and co-doped scaffolds, respectively. In summary, F- and Sr-doping offered the highest bioactivity and cytocompatibility, respectively, whereas co-doping presented the weakest behaviors comparatively., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this research, novel monticellite/hydroxyapatite (HA) ceramic composites were successfully prepared by mechanical method. The ability of nanostructured monticellite-based ceramic composites to form a suitable bond to living hard tissues, and stimulate osteoblast-like cells proliferation may be different for various ratios of the reinforcement to monticellite matrix. The differences in physico-chemical characteristics, bone-like apatite formation, cytocompatibility, cell viability and in vitro osteogenic activity of nanostructured monticellite/HA ceramic composites were explored. The surface reactivity and bioactivity of the composite samples were evaluated in vitro in simulated body fluid (SBF). A comparative time- and dose-dependent MTT test showed that the ions release from nanostructured monticellite/HA composites dissolution significantly stimulated cell proliferation and growth than control at a certain concentration range. The cells viability exposed to the composite extract was higher than control and mineral material of bone (HA), illustrating that cytocompatibility was improved due to the presence of magnesium (Mg) and silicon (Si) elements in the composite structure. The comparative results of alkaline phosphatase (ALP) bioactivity assay showed that the osteogenic proliferation of osteoblast-like G292 cell was increased more by the ceramic composites extract than control. These comparative results demonstrated that nanostructured monticellite-based ceramic composites possessed good in vitro bioactivity, cytocompatibility and osteogenic properties, and may be utilized as the promising bioactive materials for bone tissue regeneration and replacement., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In the present study three akermanite (Ca 2 MgSi 2 O 7 ), diopside (CaMgSi 2 O 6 ) and baghdadite (Ca 3 ZrSi 2 O 9 ) applicable bioceramics were synthesized via a sol-gel based method. The combination of sol-gel method and the raw materials used in this study presents a new route for the synthesis of the mentioned bioceramics. By the use of thermal analysis, the mechanisms occurred during the synthesis of these bioceramics were investigated. The differences in the structural density and their relation with the degradation rate and mechanical properties of all three ceramics were studied. In vitro bioactivity and apatite formation mechanisms of the samples soaked in the simulated body fluid were considered. The results showed that baghdadite as a Zr-containing material has a more dense structure in comparison with the other ceramics, which leads to a lower degradation rate and also lower bioactivity. There were also main differences between akermanite and diopside as Mg-containing ceramics. Diopside showed a structure with lower porosity content compared to the akermanite samples which resulted in the lower degradation rate and higher compressive strength., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In this study, diopside bioceramic was synthesized using a mechanical milling process and subsequent heat treatment. The simplicity of experiments and also the high energy available in ball milling lead to rapid synthesis of the products in comparison with other synthesis methods. Magnesium oxide (MgO), silicon dioxide (SiO 2 ) and eggshell (as the calcium source) powders were weighted in stoichiometric conditions and milled to initial activation of the surface of the powder's mixture. Then a sintering process was conducted to complete formation of diopside nanopowder and also evaluates its thermal stability. The mechanisms occurred during the synthesis of this bioceramic were carefully investigated. X-Ray diffraction analysis (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetry (TG), differential thermal analysis (DTA), and inductive coupled plasma atomic emission spectroscopy (ICP-AES) were used for gathering and analyzing data. The ability and rate of apatite formation on the sample surface were evaluated by Simulated Body Fluid (SBF) test, a method that is well recognized to characterize the in vitro bioactivity of ceramic materials. According to the results obtained, the diopside samples had a significant potential to form apatite layer on their surface during soaking in the SBF solution. Besides, the bonding strength of this bioceramic was about 350±7MPa which was almost more than three times of that reported for hydroxyapatite. An excellent fracture toughness of 4±0.3MPam 0.5 was also obtained for this ceramic which was higher than that of previously reported works., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In recent decades, bone scaffolds have received a great attention in biomedical applications due to their critical roles in bone tissue regeneration, vascularization, and healing process. One of the main challenges of using scaffolds in bone defects is the mechanical strength mismatch between the implant and surrounding host tissue which causes stress shielding or failure of the implant during the course of treatment. In this paper, space holder method was applied to synthesize diopside/forsterite composite scaffolds with different diopside content. During the sintering process, NaCl, as spacer agent, gradually evaporated from the system and produced desirable pore size in the scaffolds. The results showed that adding 10wt.% diopside to forsterite can enormously improve the bioactivity, biodegradability, and mechanical properties of the composite scaffolds. The size of crystals and pores of the obtained scaffolds were measured to be in the range 70-100nm and 100-250μm, respectively. Composite scaffolds containing 10wt.% diopside showed similar compressive strength and Young's modulus (4.36±0.3 and 308.15±7MPa, respectively) to that of bone., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Diopside was synthesized from biowaste (Eggshell) by sol-gel combustion method at low calcination temperature and the influence of two different fuels (urea, l-alanine) on the phase formation temperature, physical and biological properties of the resultant diopside was studied. The synthesized materials were characterized by heating microscopy, FTIR, XRD, BET, SEM and EDAX techniques. BET analysis reveals particles were of submicron size with porosity in the nanometer range. Bone-like apatite deposition ability of diopside scaffolds was examined under static and circulation mode of SBF (Simulated Body Fluid). It was noticed that diopside has the capability to deposit HAP (hydroxyapatite) within the early stages of immersion. ICP-OES analysis indicates release of Ca, Mg, Si ions and removal of P ions from the SBF, but in different quantities from diopside scaffolds. Cytocompatability studies on human bone marrow stromal cells (hBMSCs) revealed good cellular attachment on the surface of diopside scaffolds and formation of extracellular matrix (ECM). This study suggests that the usage of eggshell biowaste as calcium source provides an effective substitute for synthetic starting materials to fabricate bioproducts for biomedical applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In this work, diopside based ceramics was obtained by solid state reaction using conventional sintering (CS) and microwave sintering (MS). Moreover, different amounts of P2O5 (0.5-5.0 wt.%) have been added. It has been found that a relative density up to 95% theoretical was obtained for diopside containing 2.0 and 5.0 wt.% P2O5, sintered at 1250 °C for 2h and at 1075 °C only for 15 min using CS and MS. Excellent values of micro hardness (7.4 ± 0.1 GPa) and 3 point flexural strength (about 270 MPa) for samples containing 5 wt.% P2O5, sintered at 1075 °C for 15 min using MS were measured. Besides this, a relatively low weight loss ratio has been measured (0.01%) for diopside samples containing 5 wt.% P2O5, sintered under the same conditions, after soaking in physiological salt solution for 2 days. Additionally, the bioactivity of diopside by the possibility of formation of apatite on the surface of pure diopside and diopside containing 2 wt.% of P2O5 immersed in simulated body fluid (SBF) was also confirmed. Finally, particular nano-sized of Carbonated hydroxyapatite (CHA) crystals (rice shaped) were formed and covered the surface of these samples, soaked in SBF solution for 14 days., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The high corrosion rate of Mg alloys has hindered their application in various areas, particularly for orthopedic applications. In order to decrease the corrosion rate and to improve the bioactivity, mechanical stability and cytocompatibility of the Mg alloy, nanostructured diopside (CaMgSi2O6) has been coated on AZ91 Mg alloy using a combined micro arc oxidation (MAO) and electrophoretic deposition (EPD) method. The crystalline structure, the morphology and the composition of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical corrosion test, immersion test, and compression test were used to evaluate the corrosion resistance, the in vitro bioactivity and the mechanical stability of the samples, respectively. The cytocompatibility of the samples was tested by the cell viability and the cell attachment of L-929 cells. The results confirmed that the diopside coating not only slows down the corrosion rate, but also enhances the in vitro bioactivity, mechanical stability and cytocompatibility of AZ91 Mg alloy. Therefore, Mg alloy coated with nanostructured diopside offers a promising approach for biodegradable bone implants., (Published by Elsevier B.V.)