Formation Of Hydroxyapatite Layer Research Articles

Synthesis and characterization of Nb5+ and Sm3+-doped 13–93 bioactive glass particles with improved photon transmission properties for advanced biomedical and dental applications

Bioactive glasses are renowned for their applications in dentistry, serving as restorative materials, dental adhesives, intracanal medicaments, and agents for enamel remineralization. Niobium pentoxide (Nb2O5) is employed in dental adhesive resins and orthodontic adhesives, offering radio-pacifying properties essential for dental materials. Samarium oxide (Sm2O3) emerges as a potential additive in aesthetic restorative dental ceramics and resins, enhancing the natural fluorescence of teeth. In this study Nb2O5 and Sm2O3-doped (1, 3, and 5 wt%) 13–93 bioactive glass particles were synthesized via the sol-gel method, tailored for dental implementations. We conducted a comprehensive analysis of the physical, structural, and optical properties of the resultant glass powders. Additionally, their in vitro bioactivity and ionizing radiation shielding characteristics were rigorously evaluated. The results indicate that Sm3+ ions preserve the amorphous nature of the silicate glasses, while Nb5+ incorporation leads to the crystallization of the T-Nb2O5 phase. Bioactivity assays across three physiological fluids—simulated body fluid, α-minimum essential medium, and phosphate-buffered saline, demonstrated the ability of doped glasses to facilitate hydroxyapatite layer formation, with the most pronounced bioactivity observed in phosphate-buffered saline immersed samples. Furthermore, radiation shielding simulations reveal that the addition of Nb2O5 and Sm2O3 enhances the ionizing radiation attenuation capabilities of the glasses, a property that holds significant promise for protecting against radiation in dental radiology. It can be concluded that the dual functionality of Nb5+ and Sm3+-doped bioactive glasses, which may revolutionize restorative dental practices and offer improved protection in radiological applications.

Efficacy of Ga3+ ions on structural, biological and antimicrobial activity of mesoporous lithium silicate bioactive glasses for tissue engineering

Mesoporous bioactive glass nanoparticles (MBGNPs) containing therapeutic ions have shown significant promise in the realm of hard and soft tissue repair and regeneration, owing to their multifunctional biological properties. In this study, gallium-incorporated silica-based gallium incorporated MBGNPs (Ga-MBGNPs) with fixed amount of Li2O (8 mol %) were synthesized using an emulsion-assisted sol-gel method. The impact of Ga2O3 integration into the silicate glass network was evaluated by investigating the microtextural properties. The results confirmed the production of spherical-shaped, nano-sized, amorphous particles with an enhanced specific surface area and ordered hexagonal meso-porosity (10–20 nm) in the developed Ga-MBGNPs. The in vitro bioactivity, assessed through hydroxyapatite (HAp) layer formation in simulated body fluid (SBF), over varying time intervals (0, 1, 3, 7, 14 & 21 days), revealed pronounced formation of short rod-like carbonated HAp with increasing immersion time and Ga3+ content in all glasses. However, a delayed apatite formation was observed for composition-dependent Ga-4 and Ga-5 MBGs during the initial incubation periods (1, 3, and 7 days). Further, the presence of Li + ions along with Ga3+ enhanced the apatite deposition when compared with the only Ga3+ inclusion. Evaluation of degradation rate and pH values indicated enhanced apatite formation with lower Ga ion content, while a slight reduction was noted with higher Ga ion content, attributable to the presence of reactive Si–O–Si bonds. Furthermore, analysis using a Zeta potential analyzer confirmed the dispersibility and bioreactivity of all glass powders owing to their higher negative surface charge. Moreover, Ga-MBGNPs exhibited notable antimicrobial effects against both E. coli and S. aureus bacteria due to the release of Ga3+ ions. Overall, the findings suggest that the incorporation of Ga in MBGNPs renders them potential multifunctional candidates for expediting the healing of bone tissue injuries in biomedical applications.

Devitrite (Na2Ca3Si6O16) phase dominated nanostructured 45S5 bioactive glass: exploring its structural and biological properties

This research study is primarily centred around calcination temperature and time influence on phase formation in bioactive glasses (BGs). In the present study, BG with a nominal composition of 45S5 was synthesized through the sol–gel process. The developed BGs then underwent heat treatment for various sintering durations and temperatures. X-ray diffraction (XRD) patterns of the BGs reveals that the sintering process led to the crystallization of both devitrite (Na2Ca3Si6O16) and combeite (Na2Ca2Si3O9) phases. The field emission scanning electron microscopy study divulges morphological alterations, from sheet-like to rod-like structures to eventually transforming into spherical and sheet-like structures. The surface area and Type-IV mesoporous porosity were validated through Brunauer Emmett Teller analysis, highlighting a notable increase in pore volume and mechanical strength at a lower sintering temperature. In vitro apatite formation was carried out in Hank’s balance salt in order to evaluate the bioactivity of the glass. After 7 d of immersion in simulated body fluid (SBF), XRD patterns and scanning electron microscopy micrographs results showed that formation of hydroxyapatite layer on the surface of the BGs. The BG compatibility with erythrocytes (red blood cells) was also studied, and the results revealed that there was only a low 2% lysis, showing good hemocompatibility. The drug loading and release behaviour of the BGs was studied in the in vitro analysis. The findings showed a high drug encapsulation effectiveness of up to 90% and continuous drug release from the BGs for 24 h. The materials biocompatibility was unambiguously confirmed by cytocompatibility and proliferation studies. This study provides compelling evidence for the exceptional efficacy and promise of the distinct 45S5 BGs in advancing the field of regenerative medicine.

Effect of systematic substitution of Na2O for SiO2 on devitrification and bioactivity of sol-gel derived 69.5SiO2-24.5CaO-6P2O5 ceramics

Addition of Na2O to SiO2–CaO–P2O5 glass-ceramics significantly impacts in-vivo dissolution and structural network modifications. However, achieving a vitreous state in sol-gel derived quaternary oxide powders, like the 45S5 bioglass containing high amounts of Na2O, is challenging. Synthesis of (69.5-x)SiO2-24..5CaO-6P2O5-xNa2O (x = 0, 2, 4, 8, 12, 16, 20, and 24.5 wt.%) ceramic powders has been carried out followed by heat-treatment between 500 °C and 700 °C. Structural characterization revealed that the vitreous state could be stabilized for Na2O content up-to 12wt.%. For higher Na2O content, the network transformed to a glass-ceramic state with the crystallization of combeite phase. In-vitro tests exhibited hydroxyapatite layer formation (Ca/P = 1.67) on all samples in simulated body fluid, regardless of structure. Samples were non-toxic to MG-63 osteoblast cells. The devitrification, bioactivity and associate properties of the quaternary system as a function of Na2O content is discussed with respect to envisaged biomedical applications.

Examination of bioactivity studies of phosphate glasses doped with strontium

Glass samples of the composition 45P2O5-xNa2O-(50-x)CaO-5SrO (x = 20, 25, 30, 35 mol%) were prepared by conventional melt quench method and were subjected to in vitro bioactivity studies by immersing in Simulated Body Fluid (SBF) solution with pH = 7.4 at 37 °C. In vitro bioactivity study of strontium doped phosphate glasses involves examining the interaction between the glass material and biological systems, such as cells or tissues. The crystalline phase, functional group analysis, surface morphology and elemental composition of the synthesised samples were evaluated using X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray (EDX) analyses respectively. Strontium doped phosphate glasses are a type of biomaterials that have prospective applications in the field of bone tissue engineering and regeneration. The formation of hydroxyapatite layer on the surface of glasses post immersion in SBF was confirmed by XRD and FTIR spectra. SEM micrographs revealed the formation of crystal agglomerates on the surface of glasses. EDX confirmed the presence of Ca and P ions. The fixed concentrations of phosphorus oxide and strontium oxide have been found to have an impact on the properties of the glass material, even as the amounts of sodium oxide and calcium oxide are varied. The results of these studies can yield valuable insights into the bioactivity of the glasses and their potential applications in the fields of bone tissue engineering and regeneration.

Synergistic effect of CoFe2O4–85S nano bio-glass composites for hyperthermia and controlled drug delivery

Cancer, a devastating disease is a significant cause of mortality in recent times, continues to pose formidable challenge in terms of finding effective treatments. In this context, we present a pioneering approach that combines bone tissue regeneration, hyperthermia and controlled drug delivery using nanocomposites composed of 85S (85SiO2–10CaO-5P2O5 (mol%)) bio-glass and cobalt ferrite (CoFe2O4) nanoparticles, synthesized using Stober's method and a modified microwave reflux method, respectively. The formation of hydroxyapatite (HAp) layer after immersion in simulated body fluid (SBF) is confirmed through XRD, FTIR, and SEM measurements. Among all nanocomposites, 7.5 wt% of cobalt ferrite with 85S bio-glass (CFO_7.5) demonstrates the maximum formation of a HAp, indicating its potential for bone tissue regeneration. MTT assay confirms the remarkable biocompatibility against MG-63 osteoblastic cells, displaying higher cell viability of about 220% after 72 h for CFO_7.5. Significantly, it also demonstrates remarkable antimicrobial activity against both E. coli and S. aureus cells. Although M vs H measurements show superparamagnetic behaviour at room temperature for all the nanocomposites, CFO_7.5 exhibits a gradual and consistent heating rate, making it an ideal thermo-seed material for hyperthermia applications. Besides, 80% of drug loading and 97% of cumulative release at 7.4 pH has been observed in CFO_7.5 due to its mesoporous structure and high surface area confirmed from BET analysis. In-vitro experiments provide compelling evidence of the remarkable bioactivity, potent antimicrobial and sustained drug release capabilities along with the ability to generate controlled heat that makes CFO_7.5 a potential candidate for hyperthermia and control drug delivery in treating cancer.

Fabrication and in vitro studies on bioactive borate glasses containing dopant chromium sulfate

This research aims to assess the bioactive properties of the modified borate glasses containing extremely low concentrations (≤5 mol.%) from chromium sulfate (Cr2(SO4)3). The glasses in the system xCr2(SO4)3.(60–x)B2O3.15CaO.15Na2O.10P2O5, where x = 0, 1, 2, and 5 mol.% were prepared by the melt quenching technique. All glass samples have been treated thermally at 600 °C for 6 h. Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) measurements were carried out to differentiate between the structural changes before and after soaking in the simulated body fluid (SBF) at about 37 °C for 1, 2, and 3 weeks. Glass-ceramic samples have showed sharper peaks that are identified using X-ray diffraction data. These crystalline phases are indexed to crystalline calcium borate (Ca2B2O3) and calcium phosphate (Ca3(PO4)2). In vitro tests, FTIR spectra revealed two small bands in the 560-610 cm−1 range which might be assigned to the formation of a hydroxyapatite layer (HA). The formation of HA was also confirmed by XRD results, particularly after immersion in SBF for 21 days. The study suggests that the presently studied glasses containing Cr2(SO4)3 can possess good bioactivity which might be considered to be suitable for some bio and medical applications.

High Boron Content Enhances Bioactive Glass Biodegradation.

Derived Hench bioactive glass (BaG) containing boron (B) is explored in this work as it plays an important role in bone development and regeneration. B was also found to enhance BaG dissociation. However, it is only possible to incorporate a limited amount of B. To increase the amount of B in BaG, bioactive borosilicate glasses (BaG-Bx) were fabricated based on the use of the solution-gelation process (sol-gel). In this work, a high B content (20 wt.%) in BaG, respecting the conditions of bioactivity and biodegradability required by Hench, was achieved for the first time. The capability of BaG-Bx to form an apatite phase was assessed in vitro by immersion in simulated body fluid (SBF). Then, the chemical structure and the morphological changes in the fabricated BaG-Bx (x = 0, 5, 10 and 20) were studied. The formation of hydroxyapatite (HAp) layer was observed with X-ray diffraction (XRD) and infrared (IR) spectroscopy. The presence of HAp layer was confirmed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Enhanced bioactivity and chemical stability of BaG-Bx were evaluated with an ion exchange study based on Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and energy dispersive spectroscopy (EDS). Results indicate that by increasing the concentration of B in BaG-Bx, the crystallization rate and the quality of the newly formed HAp layer on BaG-Bx surfaces can be improved. The presence of B also leads to enhanced degradation of BaGs in SBF. Accordingly, BAG-Bx can be used for bone regeneration, especially in children, because of its faster degradation as compared to B-free glass.

Bioactive Glass-Enhanced Resins: A New Denture Base Material.

The creation of the denture base material with bioactive properties that releases ions and produces hydroxyapatite. Acrylic resins were modified by the addition of 20% of four types of bioactive glasses by mixing with powders. Samples were subjected to flexural strength (1, 60 days), sorption and solubility (7 days), and ion release at pH 4 and pH 7 for 42 days. Hydroxyapatite layer formation was measured using infrared. Biomin F glass-containing samples release fluoride ions for a period of 42 days (pH = 4; Ca = 0.62 ± 0.09; P = 30.47 ± 4.35; Si = 22.9 ± 3.44; F = 3.1 ± 0.47 [mg/L]). The Biomin C (contained in the acrylic resin releases (pH = 4; Ca = 41.23 ± 6.19; P = 26.43 ± 3.96; Si = 33.63 ± 5.04 [mg/L]) ions for the same period of time. All samples have a flexural strength greater than 65 MPa after 60 days. The addition of partially silanized bioactive glasses allows for obtaining a material that releases ions over a longer period of time. This type of material could be used as a denture base material, helping to preserve oral health by preventing the demineralization of the residual dentition through the release of appropriate ions that serve as substrates for hydroxyapatite formation.

Microstructural Properties and in vitro Dissolution of Microporous Bioactive 13-93B3 Glass Powders Synthesized via Solution Combustion Synthesis

This study investigates the bioactivity and microstructural properties of borate-based bioactive 13-93B3 glass produced by the solution combustion synthesis (SCS) method using urea and sucrose fuels at different reaction temperatures. The results show these glasses exhibit unique properties compared to conventionally-synthesized borate-based bioactive glasses. The glass particles produced have porous surfaces, with particle sizes below 100 nm. BET measurements reveal that the mesoporous structure of these glasses is characterized by high-specific surface areas, promoting a high ion release and hydroxyapatite layer formation in simulated body fluid (SBF). The crystallization of the amorphous calcium phosphate was investigated by 1H, 31P MAS, and 2D 31P{1H} heteronuclear correlation (HETCOR) spectroscopy, showing that it progresses linearly up to three days. The produced glasses were tested for their effects on the viability of 3T3 cells and were found to have no toxic effects. Therefore, the produced glasses are promising candidates for tissue engineering applications.

Optical, structural and physical properties of fluoride doped bioactive glasses

Glasses of composition (60–x)NaPO3-25B2O3-xCaF2-15MgO, where x = 2.5, 5, 7.5, 10 and 12.5 mol% were synthesized by melt quench method at 1100 °C. The X ray diffractogram (XRD) of glass samples reveals their amorphous nature. Density of synthesized samples was found to increase when CaF2 composition varied from 2.5 to 12.5 mol%. UV visible absorption spectra of the samples show broad absorption band at nearly about 215 nm. The optical band gaps were estimated from the optical absorption spectra by using Tauc plots. An increase of band gap energies was observed due to the creation of ionic cross-links within the glass structure. The various other parameters like calcium ion concentration, polaron radius, internuclear distance and optical basicity values were calculated using the refractive index and density of glasses. For in vitro studies, the glasses were soaked in Simulated Body Fluid (SBF) solution for 14 days. The XRD and Infrared (IR) studies carried out on samples post immersion in SBF solution for 14 days have revealed the formation of hydroxyapatite layer.

Assessment of sol-gel derived iron oxide substituted 45S5 bioglass-ceramics for biomedical applications.

Magnetic bioactive glass-ceramic (MGC) powders with nominal compositions of (45 - x)SiO224.5CaO24.5Na2O6P2O5xFe2O3 (x = 2, 4, 6, 8, 10, and 15 wt%) have been synthesized by a sol-gel route by systematically substituting silicon dioxide with iron oxide in Hench's 45S5 glass composition. Powder X-ray diffraction studies revealed a variation in the percentage of combeite (Ca2Na2Si3O9), magnetite (Fe3O4), and hematite (Fe2O3) nanocrystalline phases in MGC powders as a function of composition. Zeta potential measurements showed that MGC containing up to 10 wt% iron oxide formed stable suspensions. The saturation magnetization and heat generation capacity of MGC fluids increased with an increase in iron oxide content. Degradation of MGC powders was investigated in phosphate buffered saline (PBS). The in vitro bioactivity of the MGC powders taken in pellet form was confirmed by observing the pH variation as well as hydroxyapatite layer (HAp) formation upon soaking in modified simulated body fluid. These studies showed a decrement in the overall bioactivity in samples with high iron oxide content due to the proportional decrease in the silanol group. Monitoring the proliferation of MG-63 osteoblast cells in Dulbecco's Modified Eagle Medium (DMEM) revealed that MGC with up to 10 wt% iron oxide exhibited acceptable viability. The systematic study revealed that the MGC with 10 wt% iron oxide exhibited optimal cell viability, magnetic properties and induction heating capacity, which were better than those of FluidMag-CT, which is used for hyperthermia treatment.

Physical–chemical and biological properties of novel resin-based composites for dental applications

Insufficient mechanical properties of hydroxyapatite-based composites prompted the search for new and effective solutions for dental applications. To improve the mechanical properties without losing the remineralization potential, the use of hybrid fillers was proposed. The first of them was based on the formation of hydroxyapatite (HA) layer on the surface of SYLOID®244 silica. The second of the investigated fillers was created by simultaneous synthesis of nanoparticles from precursors of HA and silica. The obtained fillers were extensively characterized by spectral methods including X-ray Diffractometry (XRD), Fourier-Transform Infrared Spectroscopy (FT-IR), and X-ray fluorescence (XRF), as well as by Scanning Electron Microscopy (SEM)/Energy Dispersive Spectroscopy (EDS). Tests using probiotic microorganisms were an important part of the analysis, indicating that there was no potential interaction of the materials with microflora. The tests of degree of conversion, depth of cure, opacity, sorption, solubility, flexural and compressive strength, and the remineralizing potential also showed that the composites with nano-sized silica/HA showed better mechanical properties than the composites with HA alone or commercial silica and at the same time the remineralization remained at the desired level. Thus, the proposed composite has a high application potential in the creation of implants and dental materials.Graphical abstract

Design, synthesis and structural properties of borate glasses: Towards an alkali-free bioactive glass

Glasses in the system (14-x) Na2O-(54+x) B2O3–22CaO-8MgO-2P2O5 with 0 ≤ x ≤ 14 mol%, have been prepared by the classic method, fast quenching of high-temperature melts. Multiples techniques were used to investigate their physical and structural properties such as X-ray diffraction, Density measurements, Differential scanning calorimetry, Infrared spectroscopy, Raman spectroscopy, and Isothermal heat treatment. The results found by Raman and Infrared spectroscopy show that the addition of boron oxide in different proportion and the progressive reduction of sodium oxide affect clearly the glass structure, wherewith the total elimination of Na2O the glass network exhibit the formation of an interconnected large cluster (pentaborate) at the detriment of the isolated unit containing non-bridging oxygen, thus promoting groups with four coordinated boron. The physical parameters and thermal analysis confirm the structural results found revealing an increase in the oxygen packing density and glass transition temperature from 510 °C to 640 °C indicating compactly packed structure and a reinforcement of the glass network. The isothermal treatment confirms the role of boron by maintaining the vitreous aspect until (800 °C) for the alkali-free glass, in addition to a much higher thermal stability. The bioactivity test was achieved by immersion glass samples in simulated body fluids solution (SBF) at 37 °C, these latter within a few days reveals the growth of the hydroxyapatite phase confirmed by X-ray diffraction, FT-IR, and scanning electron microscope. Also, the conversion process was proved with the increase in pH and the weight loss values as well as the consumption of Ca and P concentration in simulated body fluids solution. However, the kinetics of the reaction decreases with the substitution of Na2O with B2O3 in the glass system which is quite related to the creation of more interconnected bonds and less non-bridging oxygens. Thus the properties found of the alkali-free glass in correlation with the formation of hydroxyapatite layer indicate a potential glass for tissue engineering application.

Synthesis by Sol‐Gel Technique and Antibacterial Activity of Bioactive Hybrid SiO2 Inorganic Matrix by Different Structures of Ferrous Citrate (Fe(II)C): Comparative Study

AbstractThe aim of this work is to characterize and compare three different structures of Ferrous citrates (Fe(II)C), amorphous, semicrystalline, and crystalline incorporated into a SiO2 inorganic matrix by sol–gel technique. Fourier transform infrared spectroscopy (FTIR) confirms both the Fe(II)C presence in the silica matrix and the interactions among different components in the hybrid materials. Moreover, FTIR spectroscopy is used to evaluate the formation of hydroxyapatite layer, known as bioactivity test, of the hybrids soaked into simulated body fluid (SBF). Finally, the antibacterial properties of the hybrids are investigated.

Evaluation of the electrical and dielectric behavior of the apatite layer formed on the surface of hydroxyapatite/hardystonite/copper oxide hybrid nanocomposites for bone repair applications

The work aimed to prepare nanocomposites with good electrical and mechanical properties and acceptable bioactivity behavior to be suitable for bone repair applications. In this context, hydroxyapatite (HA) and hardystonite (HT) were prepared by mechanochemical synthesis method. Subsequently, nanocomposites of different contents of HA, HT and copper oxide (CuO) were prepared, sintered and characterized by X-ray diffraction (XRD) technique and scanning electron microscopy (SEM). In addition, bioactivity was evaluated in vitro after treatment in simulated body fluid (SBF) and HA layer formation was confirmed by SEM in conjunction with energy dispersive X-ray analysis (EDX). The electrical and dielectric properties were measured before and after treatment in SBF solution. Elastic and physical properties were also measured. The results clarified that the sintering temperature used along with the successive increase of HT and CuO contents achieved good densification behavior and better mechanical properties, especially compressive strength, to avoid the stress-shielded bone effect. Also, HT and CuO positively enhanced the electrical conductivity and reduced the dielectric properties of nanocomposites prepared. The latter results have a great role in promoting fracture healing. Based on the above results, the prepared nanocomposites are promising for potential use in bone repair applications.

Partially biodegradable Ti Mg composites prepared by microwave sintering for biomedical application

Partially biodegradable TiMg composites were prepared by microwave sintering using the elemental Ti and Mg powders. The effect of Mg contents on the microstructure, mechanical properties, corrosion resistance, Mg degradation behavior of the TiMg composites was investigated. The number of block Mg distributed over the Ti matrix gradually increases with increasing the Mg contents, in which the Mg and Ti form the metal-metal composite, and the interface of Mg and Ti is well bonded. The compressive strength of the TiMg composites gradually decreases from 625 MPa to 357 MPa with increasing the Mg contents, while the elastic modulus varies little, ranged from 4.8 GPa to 5.7 GPa. The corrosion resistance of the TiMg composites in SBF solution gradually decreases with increasing the Mg contents, resulting in the increase of hydrogen evolution amount. According to the electrochemical impedance spectroscopy, the corrosion and degradation of the TiMg composites in SBF solution can be divided into three stages: the corrosion and degradation of Mg, the formation of Mg(OH)2 layer and the dissolve of Mg(OH)2 layer coupled with the formation of hydroxyapatite layer.

In vitro evaluation and mechanical studies of MgO added borophosphate glasses for biomedical applications

The objective of current research is to evaluate the bioactive and tribological properties of the MgO doped borophosphate glass system. The glass system constituted of 40% B2O3 - (20-x) % CaO – 25% Li2O – 15% P2O5 – x % MgO (mol%), x = 0, 0.5, 01, 02, 03 and synthesized using the melt quench technique. In-vitro bioactivity was determined using simulated body fluid (SBF) at 37 °C with time intervals of 7, 14 and 21 days. Hydroxyapatite (HA) layer formation was assessed using characterization techniques like XRD, FTIR and FESEM-EDS for structural, functional and morphological analysis respectively. The effect of MgO content on microhardness and tribological properties was studied by making cylindrical shaped glass samples. MTT assay was performed for various doses (62.5–1000 μg/ml) of glass dilutions using MG-63 cell line. In-vitro bioactivity showed higher Ca/P ratio with increase in MgO content after 21 days of immersion. MgO content seemed to promote degradation of glass due to formation of open structure in glass network. Borophosphate glass having 3% MgO exhibited the highest hardness value of 5.79(±0.08) GPa with minimum specific wear rate of 1.86 × 10−11 and 1.38 × 10−11 m3/Nm at a load of 15 N and 20 N respectively. MTT assay demonstrated the non-toxic behaviour of glass samples even at a higher dose level of 1000 μg/ml which confirmed its biocompatible behaviour. The study suggests that produced MgO doped borophosphate glass exhibits essential characteristics of bioactive materials and hence could be effective in bone filling and wound healing applications.

WITHDRAWN: Effect of mixed ions of (Zr+2 and Ti+2) on the physical properties of B2O3-SiO2-P2O5-Na2O-CaO as bioactive glass system

• 29B 2 O 3 –6SiO 2 –2P 2 O 5 –25Na 2 O-38CaO bioactive glass have been prepared. • Base bioglasses were doped with different concentration of ZrO 2 and TiO 2. • The X-ray diffraction analysis, scanning electron microscope, infrared transmission spectra and UV–visible absorption spectra were recorded before and e immersed in simulated body fluid (SBF) solution. • XRD, FTIR and SEM analysis confirm the formation of hydroxyapatite layer (HA) on the surface of the glasses after implanted in SBF. The purpose of this work is studying the influence of Zr O 2 and Ti O 2 addition on the physical properties and bioactivity of the samples with formula [29 B 2 O 3 -6Si O 2 -2 P 2 O 5 -25 N a 2 O -(38-X) Ca O -X (Zr O 2 +Ti O 2 )]; 0 ≤ X ≥ 3 (mol.%). The glass samples were prepared by melt quenching technique. A set of techniques were conducted to emphasize the physical properties and bioactivity role. The density, SEM, FT-IR spectra, DSC, optical spectra, and elastic moduli were used to characterize the samples. The formation of hydroxyapatite layer was confirmed by XRD, FTIR, optical absorption and SEM analyses. The variation in the optical band gap with Zr O 2 and Ti O 2 content was discussed in terms of the changes in glass structure and the formation of HA layer. The reduction in the pH value with the augmentation in Zr O 2 +Ti O 2 content was showed. The results confirmed that the samples doping with Zr O 2 exhibit appealing properties suitable as potential bioactive glass material.

ZnO incorporated high phosphate bioactive glasses for guided bone regeneration implants: enhancement of in vitro bioactivity and antibacterial activity

Bioactive phosphate glasses incorporated with Zn 2+ (predicted to be useful for bone regeneration applications) were synthesized. Characterization of the bioglasses were done using XRD, FTIR, SEM, and EDS techniques, both prior to and after soaking in simulated body fluid (SBF) solution. The bioactive performance of samples was evaluated by incubated in SBF for different days by means of the pH measuring and comparing the results of XRD and SEM studies. The obtained results show the formation of hydroxyapatite (HAP) layer on the surface of as-developed bioactive glasses. The degradation of the samples evaluated by weight loss and pH of the remnant solution measured as functions of ZnO concentration and immersion time revealed the enhanced formation of HAP layer on the sample surface. The results further indicated the rate of degradation can be monitored by tailoring the concentration of ZnO and immersion time. The studies were also extended to in vitro cytocompatibility and cell proliferation measurements on rMSC using CCK-8 for incubation periods of 24 h and 72 h. These studies have revealed the considerable levels of rMSC proliferation and improved viability within the limits of nontoxic levels. The measurements of antibacterial activity of ZnO-doped phosphate bioactive glasses against E. coli and S. aureus, carried out for 24 h and 48 h have confirmed their potential antibacterial activity. Finally, quantitative analysis of these results confirmed an enhanced in vitro biological and antibacterial activity of the samples due to the ZnO doping and subsequent controlled release of Zn 2+ ions in the glass matrix.