Bioactive Glass 58S Research Articles

Atomic force microscopic investigations of transient early-stage bacterial adhesion and antibacterial activity of silver and ceria modified bioactive glass

Bioactive glass 58S (BG58S) is widely recognised for its bioactivity and antibacterial properties, making it a promising material for orthopaedic implant applications. This study investigates the effects of incorporating silver (BG58S-2.5Ag) and cerium oxide (BG58S-5C) into BG58S on early-stage bacterial adhesion and subsequent bacterial growth inhibition. Using a high-intensity ball milling approach, BG58S was modified with 5% cerium oxide (CeO2) and 2.5% silver (Ag) nanoparticles to create homogeneous BG58S-2.5Ag and BG58S-5C nanocomposites. Custom-made biomineral probes were employed to measure the bacterial adhesion within one second of contact with Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, using Atomic Force Microscopy (AFM). The results demonstrated that BG58S-2.5Ag showed significantly stronger transient adhesion to bacteria compared to BG58S, leading to a more effective long-term antibacterial response. Additionally, it was observed that the antibacterial effect of Ag commenced within one second of contact. These findings indicate a potential correlation between the rate of bond strengthening and cell wall penetration. This study highlights the potential for enhancing the effectiveness of antibacterial implant surfaces for various biomaterial applications.Graphical abstract

Dislodgment Resistance, Adhesive Pattern, and Dentinal Tubule Penetration of a Novel Experimental Algin Biopolymer-Incorporated Bioceramic-Based Root Canal Sealer.

The currently available bioceramic-based sealers still demonstrate low bond strength with a poor seal in root canal despite desirable biological properties. Hence, the present study aimed to determine the dislodgment resistance, adhesive pattern, and dentinal tubule penetration of a novel experimental algin-incorporated bioactive glass 58S calcium silicate-based (Bio-G) sealer and compared it with commercialised bioceramic-based sealers. A total of 112 lower premolars were instrumented to size 30. Four groups (n = 16) were assigned for the dislodgment resistance test: control, gutta-percha + Bio-G, gutta-percha + BioRoot RCS, and gutta-percha + iRoot SP, with exclusion of the control group in adhesive pattern and dentinal tubule penetration tests. Obturation was done, and teeth were placed in an incubator to allow sealer setting. For the dentinal tubule penetration test, sealers were mixed with 0.1% of rhodamine B dye. Subsequently, teeth were cut into a 1 mm-thick cross section at 5 mm and 10 mm levels from the root apex, respectively. Push-out bond strength, adhesive pattern, and dentinal tubule penetration tests were performed. Bio-G showed the highest mean push-out bond strength (p < 0.05), while iRoot SP showed the greatest sealer penetration (p < 0.05). Bio-G demonstrated more favourable adhesive patterns. No significant association was noted between dislodgment resistance and dentinal tubule penetration (p > 0.05).

Fabrication and characterisation of novel algin incorporated bioactive-glass 58S calcium-silicate-based root canal sealer

The usage of bioceramic-based root canal sealers has escalated over the years due to their excellent properties. The present study aimed to fabricate a novel algin incorporated bioactive glass 58S calcium-silicate (Bio-G) sealer and characterise its surface microstructure and chemical compositions in comparison to commercially available bioceramic sealers (BioRoot RCS and iRoot SP). The powder form of experimental Bio-G sealer consisted of synthesised BG 58S particle, calcium silicate, zirconia dioxide, calcium carbonate and alginic acid powder as binder. The liquid composed of 5% calcium chloride solution. Five standardised disc specimens were prepared for each sealer group according to the manufacturer's instructions. Subsequently, sealer disc-specimens were placed in an incubator at 37°C, 95% relative humidity for 72h to allow setting prior to testing under scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Experimental Bio-G sealer revealed irregular micro-sized particles ranging from 0.5μm to 105μm aggregated in clusters comparable to those of BioRoot RCS and iRoot SP. EDS microanalysis showed that Bio-G had high content of oxygen, silicon, and calcium, with the presence of aluminium and chloride similar to BioRoot RCS. Meanwhile, the FTIR and XRD findings suggested that all sealers predominantly contained calcium silicate hydrate, calcium carbonate, and zirconium dioxide, while calcium aluminium silicate oxide was detected in Bio-G. The present novel Bio-G sealer demonstrated desirable particle size distribution and acceptable degree of purity. Future studies are warranted to explore its properties and clinical application.

Effect of ammonia catalyst on the morphological structures of sol–gel‐derived bioactive glass 58S for dental application

AbstractAimTo determine the effect of ammonia on the surface morphology and chemical properties of sol–gel‐derived bioactive glass 58S powders for dental application.Materials and MethodsBioactive glass (BG) 58S powder was synthesized using a sol–gel method. Hydrochloric acid solution was mixed with ethanol, distilled water, and tetraethyl orthosilicate for 30 min, followed by the addition of triethyl phosphate and calcium nitrate tetrahydrate. The mixture was stirred until the particles were completely dissolved. Three different groups were prepared: BG‐1 (no ammonia added), BG‐2 (3 ml of ammonia added), and BG‐3 (5 ml of ammonia added). The gel was then aged and calcined. The solidified gel was crushed until the powder passed through a 200‐μm sieve. Subsequently, the surface morphology was evaluated using a scanning electron microscopy, whereas the chemical composition was assessed using a Fourier transform infrared spectroscopy (FTIR).ResultsBG‐2 and BG‐3 exhibited small‐sized cluster grains and a more porous micro‐ or nano‐structures. The crystallinity of the BG powder and its surface porosity increased with increased ammonia. The average microparticle sizes of the BG‐1, BG‐2, and BG‐3 were 196 ± 31, 45 ± 21, and 20 ± 9 μm, respectively, with nano‐grains in BG‐2 and BG‐3 showed strong tendency of agglomeration. FTIR verified the existence of a silica network‐based glass, with the Si–O–Si functional group visible in the spectrum of all groups.ConclusionThe addition of ammonia as catalyst during the hydrolysis process resulted in small glassy grains and more porous surfaces of BG 58S, which is anticipated to promote greater bioactivity.

Effect of low temperature crystallization on 58S bioactive glass sintering and compressive strength

Mesoporous glass 58S (60SiO2, 36CaO, 4P2O5 mol.%) has excellent bioactivity, biocompatibility, and forms strong bonds with bone making it attractive for implants. Mesoporous bioactive glass 58S powder is typically consolidated through sintering in order to produce an implant with sufficient strength to withstand the in vivo loads. However, heating the glass often leads to crystallinity, which is undesirable because it can reduce bioactivity. Hence, there is a trade-off between minimising crystallinity and maximising glass strength. Even at relatively low temperatures, it has been suggested that segregation of calcium and phosphate from silica within the glass can lead to crystallization. In this work, we confirm the occurrence of low temperature segregation in bioactive glass 58S using electron microscopy with elemental mapping. We probe how segregation affects the material properties of post-sintered glasses via comparison to a glass where phase separation is prevented via addition citric acid to the parent sol.

Sol-Gel Synthesis, in vitro Behavior, and Human Bone Marrow-Derived Mesenchymal Stem Cell Differentiation and Proliferation of Bioactive Glass 58S

Background:Bioactive glasses 58S, are silicate-based materials containing calcium and phosphate, which dissolved in body fluid and bond to the bone tissue. This type of bioactive glass is highly biocompatible and has a wide range of clinical applications. Methods:The 58S glass powders were synthesized via sol-gel methods, using tetraethyl orthosilicate, triethyl phosphate, and calcium nitrate, as precursors. Upon the analyses of phase and chemical structures of bioactive glass in different gelation times (12, 48, and 100 h), the appropriate heat treatment (at 525, 575, and 625 °C) was performed to eliminate nitrate compounds and stabilize the glass powder samples. The in vitro assay in SBF solution revealed the bioactivity of the synthesized 58S glass through the morphological (SEM), chemical structure (FTIR), release of calcium, phosphorous and silicon elements, pH variations, and weight loss measurements. The behavior of MSCs in the presence of bioactive glass powders was studied by MTT cytotoxicity, cell staining, ALP activity and biomineralization tests, as well as by the evaluation of ALP, osteocalcin, osteonectin, collagen I, and RUNX2 gene expression. Results: The results confirmed a gelation time of 100 h and a calcination temperature of 575 °C at optimal conditions for the synthesis of nitrate-free bioactive glass powders. Conclusion:The glass spherical nanoparticles in the range of 20-30 nm possess the improved bioactivity and osteogenic properties as demanded for bone tissue engineering.

Sol-Gel Synthesis, in vitro Behavior, and Human Bone Marrow-Derived Mesenchymal Stem Cell Differentiation and Proliferation of Bioactive Glass 58S.

Bioactive glasses 58S, are silicate-based materials containing calcium and phosphate, which dissolved in body fluid and bond to the bone tissue. This type of bioactive glass is highly biocompatible and has a wide range of clinical applications. The 58S glass powders were synthesized via sol-gel methods, using tetraethyl orthosilicate, triethyl phosphate, and calcium nitrate, as precursors. Upon the analyses of phase and chemical structures of bioactive glass in different gelation times (12, 48, and 100 h), the appropriate heat treatment (at 525, 575, and 625 °C) was performed to eliminate nitrate compounds and stabilize the glass powder samples. The in vitro assay in SBF solution revealed the bioactivity of the synthesized 58S glass through the morphological (SEM), chemical structure (FTIR), release of calcium, phosphorous and silicon elements, pH variations, and weight loss measurements. The behavior of MSCs in the presence of bioactive glass powders was studied by MTT cytotoxicity, cell staining, ALP activity and biomineralization tests, as well as by the evaluation of ALP, osteocalcin, osteonectin, collagen I, and RUNX2 gene expression. The results confirmed a gelation time of 100 h and a calcination temperature of 575 °C at optimal conditions for the synthesis of nitrate-free bioactive glass powders. The glass spherical nanoparticles in the range of 20-30 nm possess the improved bioactivity and osteogenic properties as demanded for bone tissue engineering.

Evaluation of bioactive glass synthesized by alkali‐mediated sol‐gel process

AbstractThe main objective of this research is the elaboration of bioactive glass 58S by an alkali‐mediated sol‐gel method. In which, the ammonia solution was used to transfer sol to gel state, and then the gel was dried by using the free‐drying technique. The dried gel was heated at 700°C in 2 h to convert into glass powder. The XRD analysis confirmed the amorphous and glassy properties of synthetic bioglass. The specific surface area of 99.146 m2/g of this bioglass was identified by using a low‐temperature nitrogen adsorption technique. In vitro experiments were performed by soaking the powder samples in the simulated body fluid (SBF) at several times. The XRD patterns and SEM images high lighted the bioactivity of bioglass by the formation of a dense and visible hydroxyapatite layer on the glass's surface after only 2 days of in vitro assays. ICP‐OES spectrometry was also used to illustrate the ion exchange behaviors between the bioactive glass 58S and the SBF solution.

Bioactive glass 58S prepared using an innovation sol-gel process

A 58S bioglass with a composition in the ternary system 58SiO2-33CaO-9P2O5 (wt.%) was prepared by an innovation sol-gel process in which a small amount of ammonia was used to facilitate the condensation reactions within an acidic solution prepared by tetraethyl orthosilicate, triethyl phosphate and calcium nitrate tetrahydrate. The properties of synthetic glass were investigated by several techniques. The amorphous nature and high specific surface area (99.1m2/g) of the obtained glass were confirmed by using X-ray diffraction and low-temperature nitrogen adsorption techniques, respectively. In vitro experiments were performed by soaking glass samples in the simulated body fluid (SBF). The XRD patterns and SEM images confirmed the bioactivity of the synthesized bioglass by formation of a dense and visible hydroxyapatite layer on its surface after 2 days of in vitro assays. The ICP-OES data illustrated the ion exchange behaviours between the bioglass 58S and the SBF solution.

Synthesizing and Characterizing of Gelatin-Chitosan-Bioactive Glass (58s) Scaffolds for Bone Tissue Engineering

Nowadays repairing and regenerating of lost or damaged tissue still remain an important challenge in clinical techniques. Due to the variety of available bone grafts, different types of biodegradable materials are being utilized as a scaffold implant. The basic structure of the bone is an excellent natural composite which contains varieties of polymers and ceramics; therefore, it is important to manufacture a bone scaffold featuring sufficient mechanical strength, a good degree of biocompatibility, biodegradation and an increased rate of formation of new tissue. Bioactive glass has an appealing characteristic which can be utilized for repairing purposes as well as to cause a rapid response from the bone graft. In this study, a composite scaffold based on polymer matrix (gelatin-chitosan) and bioactive glass 58s was synthesized in the laboratory. Five samples of polymer scaffold with different proportions of bioactive glass were designed and investigated. The scaffolds were dried with freeze dryer, and a spongy structure was generated. The composite survey was carried out through FTIR technique to examine the crystallization of the structure, XRD to examine the morphology of the porosities, and SEM to examine the size of porosities and formation of apatite. This study reveals that the size of porosities is about 170–320 μm, which is suitable for angiogenesis and cell growth in the bone. The combination of enhanced properties and the formation of apatite on the surface of the scaffolds make them an ideal option as a bone substitute.

Synthesis and dissolution behaviour of CaO/SrO-containing sol–gel-derived 58S glasses

The effect of the substitution of strontium for calcium in the tertiary the SiO2–CaO–P2O5 sol–gel bioactive glass 58S (60SiO2·36CaO·4P2O5, mol%) on its structure and its chemical durability on soaking in simulated body fluids was investigated. 58S was selected as a starting composition, and substitution for calcium was carried out from 0 to 100% with an increment of 25%. A novel phosphate source of diethylphosphatoethyltriethoxysilane, which consists of Si and P connected with ethylene group, was used in this work. XRD and FTIR showed that the gels obtained following drying at 130 °C had a typical sol–gel structure, where a continuous amorphous silica gel network and surface bound mineral salts of Ca(NO3)2 and Sr(NO3)2. Once the gels were heat stabilised to decompose nitrates and incorporate the cations into the network, samples containing Sr formed a strontium silicate crystalline phase. With increasing levels of Sr in the composition, the overall crystallinity of the glass–ceramic increased, while, at the maximum substitution of 100% SrO, macroscopic phase separation was observed, characterised by needle-like crystals of strontium apatite (Sr5(PO4)3OH) and strontium silicate (Sr2SiO4) phases in addition to amorphous regions. Dissolution experiments in Tris-buffered solution showed Sr successfully released into the media even though it existed as a crystalline phase in the glass–ceramic. Further, the glass–ceramics induced nucleation and growth of carbonated hydroxyapatite (HA) on their surface suggesting potential bioactivity of the materials. At higher substitutions (75 and 100% SrO for CaO), HA nucleation was not found to occur this may have been due to low amount of phosphate released from the original glass–ceramic as a result of it being locked up in the strontium apatite phase.

Healing effect of bioactive glass ointment on full-thickness skin wounds

This study aimed to investigate the effect of bioactive glasses on cutaneous wound healing in both normal rats and streptozotocin-induced diabetic rats. Bioactive glass ointments, prepared by mixing the sol–gel bioactive glass 58S (SGBG-58S), nanobioactive glass (NBG-58S) and the melt-derived 45S5 bioactive glass (45S5) powder with Vaseline (V) at 18% weight percentage, were used to heal full thickness excision wounds. Pure V was used as control in this study. Compared to SGBG-58S, NBG-58S consists of relatively dispersible nanoparticles with smaller size. The analysis of wound healing rate and wound healing time showed that bioactive glasses promoted wound healing. The ointments containing SGBG-58S and NBG-58S healed the wounds more quickly and efficiently than the ointment containing 45S5. Histological examination indicated that bioactive glasses promoted the proliferation of fibroblasts and growth of granulation tissue. Immunohistochemical staining showed that the production of two growth factors, VEGF and FGF2, which are beneficial to wound healing, was also stimulated during the healing process. Transmission electron microscope observations showed that fibroblasts in wounds treated with bioactive glasses contained more rough endoplasmic reticula and had formed new capillary microvessels by the seventh day. The effects of SGBG-58S and NBG-58S were better than those of 45S5. All results suggest that bioactive glasses, especially SGBG-58S and NBG-58S, can accelerate the recovery of skin wounds in both normal and diabetes-impaired healing models and have a great potential for use in wound repair in the future.

Sol–gel based fabrication of novel glass-ceramics and composites for dental applications

The aim of this study is the fabrication of dental glass-ceramics able to elicit bioactive behaviour around the margins of fixed restorations and to provide a bioactive surface which can lead to periodontal tissue attachment, providing complete sealing of the marginal gap between tooth and fixed prosthesis. Sol–gel technique is applied for the fabrication of a new glass-ceramic in the system SiO 260%–P 2O 53%–Al 2O 314%–CaO6%–Na 2O7%–K 2O10% (wt.%) and a related composite material combining this phase with the bioactive glass 58S. This composite material aims to create a bioactive surface which could lead to periodontal tissue attachment, providing complete sealing of the marginal gap between tooth and fixed prosthesis. The microstructural and thermal properties and the bioactive behaviour of the new materials were determined and were observed to be similar in respect to a commercial leucite based fluorapatite dental glass-ceramic. The feasibility of the new composite material to be applied as coating on the base porcelain as well as the bioactive behaviour of the fabricated coated specimes were confirmed.

Study of the Bioactive Behavior of Thermally Treated Modified 58S Bioactive Glass

Thermal treatment of bioactive glasses can affect their microstructure and thus their bioactivity. The aim of this study was the characterization of the thermally treated sol-gel-derived bioactive glass 58S at characteristic temperatures and the dependence of its bioactive behavior on the specific thermal treatment. The thermal behavior of the bioactive glass was studied by thermal analysis (TG/DTA). Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffractometry (XRD) were used for the characterization of the bioactive glass. The bioactive behavior in Simulated Body Fluid (SBF) was examined by Scanning Electron Microscopy (SEM-EDS) and FTIR. The major crystal phases after thermal treatment were Calcium Silicates, Wollastonite and Pseudowollastonite, while all thermally treated samples developed apatite after 48 hours in SBF. A slight enhancement of bioactivity was observed for the samples heated at the temperature range 910-970oC.