Glass Implants Research Articles

Titanium-doped phosphate glasses containing zinc and strontium applied in bone regeneration

Phosphate bioactive glass has been studied for its advanced biodegradability and active ion release capability. Our previous research found that phosphate glass containing (P2O5)–(Na2O)–(TiO2)–(CaO)–(SrO) or (ZnO) showed good biocompatibility with MG63 and hMSCs. This study further investigated the application of 5 mol% zinc oxide or 17.5 mol% strontium oxide in titanium-doped phosphate glass for bone tissue engineering. Ti-Ca-Na-Phosphate glasses, incorporating 5% zinc oxide or 17.5% strontium oxide, were made with melting quenching technology. The pre-osteoblast cell line MC3T3-E1 was cultured for indirect contact tests with graded diluted phosphate glass extractions and for direct contact tests by seeding cells on glass disks. The cell viability and cytotoxicity were analysed in vitro over 7 days. In vivo studies utilized the tibial defect model with or without glass implants. The micro-CT analysis was performed after surgery and then at 2, 6, and 12 weeks. Extractions from both zinc and strontium phosphate glasses showed no negative impact on MC3T3-E1 cell viability. Notably, non-diluted Zn-Ti-Ca-Na-phosphate glass extracts significantly increased cell viability by 116.8% (P < 0.01). Furthermore, MC3T3-E1 cells cultured with phosphate glass disks exhibited no increase in LDH release compared with the control group. Micro-CT images revealed that, over 12 weeks, both zinc-doped and strontium-doped phosphate glasses demonstrated good bone incorporation and longevity compared to the no-implant control. Titanium-doped phosphate glasses containing 5 mol% zinc oxide, or 17.5 mol% strontium oxide have promising application potential for bone regeneration research.Graphical

Sublabial bioactive glass implantation for the management of primary atrophic rhinitis and empty nose syndrome: Operative technique.

ObjectivesAtrophic rhinitis (AR) and empty nose syndrome (ENS) are chronic diseases characterized by a paradoxical nasal obstruction. These rare syndromes tend to occur after nasal surgery of the inferior turbinates in ENS and can be idiopathic in AR. Medical treatments alone are often insufficient. Surgical options are challenging and numerous resorbable and nonresorbable implants have been described in small series, with as many surgical techniques described. Whereas current surgical procedures are for risk of extrusions, graft rejections or poor lasting results, the use of GlassBONE™ (Sodimed®, Avignon, France), a bioactive glass, for a vestibular approach in AR and ENS has never been reported for this indication.MethodsWe described an original technique of nasal submucoperiosteal bilateral ceramic glass implantation in two patients with AR and ENS.ResultsThe two cases presented a postoperative satisfying endoscopic and sinus CT‐scan results with filling of the nasal cavities, with less crusts and a complete wound healing. They had no short‐term complications.ConclusionThis innovative approach is easily feasible and could be an option considered for the surgical management of AR and ENS. Level of evidence: 4.

Mid-term clinical results of chronic cavitary long bone osteomyelitis treatment using S53P4 bioactive glass: a multi-center study.

Introduction: Chronic osteomyelitis is a challenging condition in the orthopedic practice and traditionally treated using local and systemic antibiotics in a two-stage surgical procedure. With the introduction of the antimicrobial biomaterial S53P4 bioactive glass (Bonalive®), chronic osteomyelitis can be treated in a one-stage procedure. This study evaluated the mid-term clinical results of patients treated with S53P4 bioactive glass for long bone chronic osteomyelitis. Methods: In this prospective multi-center study, patients from two different university medical centers in the Netherlands were included. One-stage treatment consisted of debridement surgery, implantation of S53P4 bioactive glass, and treatment with culture-based systemic antibiotics. If required, wound closure by a plastic surgeon was performed. The primary outcome was the eradication of infection, and a secondary statistical analysis was performed on probable risk factors for treatment failure. Results: In total, 78 patients with chronic cavitary long bone osteomyelitis were included. Follow-up was at least 12 months (mean 46; standard deviation, SD, 20), and 69 patients were treated in a one-stage procedure. Overall infection eradication was 85 %, and 1-year infection-free survival was 89 %. Primary closure versus local/muscular flap coverage is the only risk factor for treatment failure. Conclusion: With 85 % eradication of infection, S53P4 bioactive glass is an effective biomaterial in the treatment of chronic osteomyelitis in a one-stage procedure. A major risk factor for treatment failure is the necessity for local/free muscle flap coverage. These results confirm earlier published data, and together with the fundamentally different antimicrobial pathways without antibiotic resistance, S53P4 bioactive glass is a recommendable biomaterial for chronic osteomyelitis treatment and might be beneficial over other biomaterials.

Особливості регенераторних реакцій при заповненні дефектів кісткової тканини біосклом у поєднанні з автологічною плазмою, збагаченою тромбоцитами

Проведено порівняльний морфометричний аналіз між показниками фіброретикулярної та кісткової тканини, що сформувалася в дефекті кістки після імплантації біоскла, а також біоскла з уведенням автоплазми, збагаченої тромбоцитами. В серії досліджень із додатковим уведенням автогенної плазми, збагаченої тромбоцитами, виявлено підвищення в дефекті кісткової тканини на 9 % (P &lt; 0,001). Біоскло характеризується остеокондуктивністю й остеоінтеграцією, матеріал біологічно активний, що проявляється формуванням на його поверхні активних остеобластів і кісткової тканини, часткової резорбції остеокластами. Навколо частинок біоскла були відсутні запальні прояви та алергічна реакція, матеріал був сумісний із кістковою тканиною та кістковим мозком. Деструктивних порушень кісткового мозку навколо частинок біоактивного скла не зафіксовано. Локальне введення плазми, збагаченої тромбоцитами, сприяло підвищенню остеоіндуктивних властивостей біоскла в ділянці травматичного пошкодження.

Research on Polyethylene Glycol, Crosslinked Polyethylene Glycol &amp; Polyethylene Glycol Chitosan Conjugate Coating for Biomedical Application

Polyethylene glycol used as coating materials because it resist to protein adsorption and bacterial adhesion. Polyethylene glycol and crosslinked polyethylene glycol &amp; polyethylene glycol chitosan conjugate used for coating glass implants. Fourier transform infrared spectroscopy (FTIR) analysis showed proper crosslinking in crosslinked polyethylene glycol but in polyethylene glycol &amp; chitosan conjugate no reaction takes place. Scanned Electron Microscope (SEM) used for study of surface morphology. Polyethylene glycol &amp; chitosan conjugate have smoother surface than pure polyethylene glycol, polyethylene glycol chitosan conjugate. Differential scanning calorimetry (DSC) analysis used for glass transition temperature study. Crosslinked polyethylene glycol has good mechanical properties. Antimicrobial properties of polyethylene glycol chitosan conjugate are good in comparison to pure polyethylene glycol, crosslinked polyethylene glycol.

Development of Bifacial n‐Type Front‐and‐Back Contact Cells with Phosphorus Back Surface Field via Mask‐Free Approaches

Industrial bifacial n‐type front‐and‐back contact (nFAB) solar cells consist of a boron‐doped p+ emitter and a phosphorus‐doped n+ back surface field (BSF). A conventional BSF formation method with tube‐based POCl3 diffusion typically requires the use of a masking layer to protect the front emitter against cross doping or two wet‐chemical etching steps. Herein, two alternative mask‐free BSF formation approaches are investigated, either via phosphorus ion implantation or atmospheric pressure chemical vapor deposition (APCVD) of phosphosilicate glass (PSG). The fabricated cells indicate comparable efficiencies achievable by mask‐free methods, as compared with conventional tube‐based POCl3 diffusion. In addition, the APCVD process is further improved by optimizing the phosphorus contents in the PSG layer. Cell performances with different phosphorus contents and thus different BSF sheet resistances are studied. A lower phosphorus content (higher BSF's sheet resistance) improves cells' Jsc, whereas a higher phosphorous content results in high fill factor (FF) due to better rear contact resistance and low BSF sheet resistance. The optimized condition results in nFAB cell with a peak efficiency of 21.4% and FF values over 81.0%.

Chitin Facilitated Mineralization in the Eastern Oyster

Chitin is often reported in molluscan shell, where it likely contributes to the mechanical strength of the biomineral. However, the role of this polysaccharide in relation to the process of shell formation is not well understood. We investigated the deposition of chitin during shell repair in the Eastern oysters, Crassostrea virginica, by inserting stainless steel and glass implants in a region of shell damage. This work documents the time course of deposition of both chitin fibrils and calcium carbonate layers. Chitin is detected by confocal laser scanning microscopy (CLSM) using a chitin-specific fluorescent probe that was produced from clones of a chitin-binding domain. The presence of fibrils was confirmed using electron microscopy of implants. The fibrils’ dimensions were reduced after treatment with both acid and bleach, suggesting that chitin interacts with inorganic minerals and other organic components such as proteins and lipid as early as in 5 hours after shell damage. With CLSM, it was shown that chitin co-localized with membrane, suggesting the importance of cells located on the implants in the process of fibril formation. Using observations from this study as well as those from the literature on chitin synthase production in molluscs and fungi, we propose a cellular mechanism of chitin deposition related to shell formation.

Evaluation of in vitro and in vivo biocompatibility and structure of cobalt-releasing sol-gel bioactive glass

Cobalt (Co) ions have the potential to improve angiogenesis due to its stabilizing effect on hypoxia-inducible factor 1 (HIF-1α), and its incorporation into bioactive glasses as a therapeutic ion have recently attracted great attention from the research community. However, despite its promising properties, the effect of Co on the glass structure and its biocompatibility is yet to be studied in detail. Therefore, we synthesized a novel sol-gel derived bioactive glass in the SiO2-CaO-P2O5-CoO system, and performed its structural and biological evaluation. Co-containing bioactive glass with high surface area, nanoporosity, amorphous structure, and sustained ion release was obtained. In vitro biocompatibility was confirmed by MTT assay, and no cytotoxicity was observed in human adipose stem cells (hASCs) and human umbilical vein endothelial cells (HUVECs). In vivo responses showed no adverse reactions and indicated the presence of neoformed vessels after bioactive glass implantation in the dorsum of rats, which is the characteristic of a high angiogenesis level due Co release. The results confirmed the biocompatibility of Co-releasing bioactive glass. Thus, Co-incorporation as a therapeutic ion is a potential strategy to obtain superior materials for tissue repair.

Review - bioactive glass implants for potential application in structural bone repair

AbstractBioactive glass particles andweak scaffolds have been used to heal small contained bone defects but an unmet challenge is the development of bioactive glass implants with the requisite mechanical reliability and in vivo performance to heal structural bone defects. Inadequate mechanical strength and a brittle mechanical response have been key concerns in the use of bioactive glass scaffolds in structural bone repair. Recent research has shown the capacity to create strong porous bioactive glass scaffolds and the ability of these scaffolds to heal segmental bone defects in small and large rodents at a rate comparable to autogenous bone grafts. Loading these strong porous scaffolds with bone morphogenetic protein-2 can significantly enhance their ability to regenerate bone. Recentwork has also shown that coating the external surface of strong porous scaffolds with an adherent biodegradable polymer can dramatically improve their load-bearing capacity in flexural loading and their work of fracture (a measure of toughness). These tough and strong bioactive glass-polymer composites with an internal architecture conducive to bone infiltration could provide optimal synthetic implants for structural bone repair.

Characterization of Mechanically Matched Hydrogel Coatings to Improve the Biocompatibility of Neural Implants

Glial scar is a significant barrier to neural implant function. Micromotion between the implant and tissue is suspected to be a key driver of glial scar formation around neural implants. This study explores the ability of soft hydrogel coatings to modulate glial scar formation by reducing local strain. PEG hydrogels with controllable thickness and elastic moduli were formed on the surface of neural probes. These coatings significantly reduced the local strain resulting from micromotion around the implants. Coated implants were found to significantly reduce scarring in vivo, compared to hard implants of identical diameter. Increasing implant diameter was found to significantly increase scarring for glass implants, as well as increase local BBB permeability, increase macrophage activation, and decrease the local neural density. These results highlight the tradeoff in mechanical benefit with the size effects from increasing the overall diameter following the addition of a hydrogel coating. This study emphasizes the importance of both mechanical and geometric factors of neural implants on chronic timescales.

Dynamically stable nanostructures in heavy-ion implanted silica glass

Previously reported experimental data have been used for kinetic analysis of the dynamically stable structure formation under implantation of 60 keV Au– or Cu– ions into silica glass. The kinetics has been analyzed in the frame of the one-dimensional model of evolution of the implant depth distribution, with taking into account the surface recession due to sputtering, as is also, with considering the local implant production, drift and diffusion.The kinetic analysis has shown that the maximum number of implanted atoms retained in the irradiated substrate (maximum retained ion fluence) is independent of detailed ion-range distribution. The maximum retained ion fluence depends on ratios between the following quantities: the ion flux, the mean projectile range, the surface recession rate, the implant drift velocity and the implant diffusion coefficient. A method has been proposed for evaluation of the surface recession's role in the saturation kinetics. Estimations conducted for 60 keV Au– ion implantation of silica glass have shown that the surface recession predominates in the saturation kinetics.Surface recession does not dominate for 60 keV Cu– ion implantation of silica glass. Formation of dynamically stable structures during 60 keV Cu– ion implantation of silica glass cannot be explained if the drift of implants is excluded from considerations. Considerations have shown that the drift's contribution increases with increasing the ion flux. A mechanism of depleted region formation in the dynamically stable structures has been demonstrated. According to this mechanism, formation of a depleted region within the implanted layer is caused by expelling effect of electric field from the region where the electric field is zero. Necessary drift velocity is provided by Cu+ solutes. A method utilizing images of the dynamically stable structures has been proposed for evaluation of the implant drift's role in the saturation kinetics.

On the fabrication of bioactive glass implants for bone regeneration by laser assisted rapid prototyping based on laser cladding

The processing of bioceramic materials is a topic of great interest for bone regeneration; bioceramic implants are specifically appropriate for low-load applications, such as cranioplasty. In the present study, we investigated the capabilities of rapid prototyping based on laser cladding to generate three-dimensional bioactive glass implants without moulds or preplaced powder bed. 45S5 bioactive glass and lower crystallization tendency S520 bioactive glass particles were successfully injected and melted to obtain glass-derived implants with similar mechanical properties to the precursor materials. The role of processing parameters in the process outcome was analysed: optimization of the assist gas volumetric flow, the precursor glass mass flow, the substrate preheating, and the optical power of the CO2 infrared laser beam, allowed to adjust the material cooling rates to preclude extensive crystallization or cracking. The assessment of calcium hydroxyapatite precipitation ability and ion release in simulated body fluid conclude the potential osteoconductivity of the produced implants.

Bioactive glasses—structure and properties.

Bioactive glasses were the first synthetic materials to show bonding to bone, and they are successfully used for bone regeneration. They can degrade in the body at a rate matching that of bone formation, and through a combination of apatite crystallization on their surface and ion release they stimulate bone cell proliferation, which results in the formation of new bone. Despite their excellent properties and although they have been in clinical use for nearly thirty years, their current range of clinical applications is still small. Latest research focuses on developing new compositions to address clinical needs, including glasses for treating osteoporosis, with antibacterial properties, or for the sintering of scaffolds with improved mechanical stability. This Review discusses how the glass structure controls the properties, and shows how a structure-based design may pave the way towards new bioactive glass implants for bone regeneration.

Histological Study of the Effect of Bioactive Glass on Tibial Bone Repair in Rats

The main goal of this study was to histologically evaluate the healing of surgically created defects on the tibiae of adult rats after implantation of bioactive glass. Twenty adult Wistar rats (body weight of 300g) were divided into two groups: bioglass treated group (n=10) and control group (n=10). Unicortical bone defects with 3-mm diameter were performed in both tibiae of the animals and filled with bioglass particles. The rats were then sacrificed at 14, 30 , 60 and 90 days, and the tissues were prepared for histological processing, sectioning, and staining with hematoxylin and eosin, as well as Mallory trichrome, and analyzed under light microscope. Within 7-14 days, both groups presented connective tissue septa with new bone formation, more intense in bioglass treated group. In the subsequent periods (30, 60 and 90 days), these groups presented more mature bone tissue around the glass particles. Bone trabeculae formed in all experimental periods were juxtaposed to the glass particles. It can be concluded that bioglass materials promoted bone formation over the entire extension of the defect, independently of the size of the granules, thus confirming their biological osteoconductive property.

RETRACTED: Copper-doped borosilicate bioactive glass scaffolds with improved angiogenic and osteogenic capacity for repairing osseous defects

There is growing interest in the use of synthetic biomaterials to deliver inorganic ions that are known to stimulate angiogenesis and osteogenesis in vivo. In the present study, we investigated the effects of varying amounts of copper in a bioactive glass on the response of human bone marrow-derived mesenchymal stem cells (hBMSCs) in vitro and on blood vessel formation and bone regeneration in rat calvarial defects in vivo. Porous scaffolds of a borosilicate bioactive glass (composition 6Na2O, 8K2O, 8MgO, 22CaO, 36B2O3, 18SiO2, 2P2O5, mol.%) doped with 0.5, 1.0 and 3.0wt.% CuO were created using a foam replication method. When immersed in simulated body fluid, the scaffolds released Cu ions into the medium and converted to hydroxyapatite. At the concentrations used, the Cu in the glass was not toxic to the hBMSCs cultured on the scaffolds in vitro. The alkaline phosphatase activity of the hBMSCs and the expression levels of angiogenic-related genes (vascular endothelial growth factor and basic fibroblast growth factor) and osteogenic-related genes (runt-related transcription factor 2, bone morphogenetic protein-2 and osteopontin) increased significantly with increasing amount of Cu in the glass. When implanted in rat calvarial defects in vivo, the scaffolds (3wt.% CuO) significantly enhanced both blood vessel formation and bone regeneration in the defects at 8weeks post-implantation. These results show that doping bioactive glass implants with Cu is a promising approach for enhancing angiogenesis and osteogenesis in the healing of osseous defects.

Evaluation of borate bioactive glass scaffolds as a controlled delivery system for copper ions in stimulating osteogenesis and angiogenesis in bone healing.

Biocompatible synthetic scaffolds with enhanced osteogenic and angiogenic capacity are of great interest for the repair of large (critical size) bone defects. In this study, we investigated an approach based on the controlled delivery of copper (Cu) ions from borate bioactive glass scaffolds for stimulating angiogenesis and osteogenesis in a rodent calvarial defect model. Borate glass scaffolds (pore size = 200-400 μm) doped with varying amounts of Cu (0-3.0 wt% CuO) were created using a polymer foam replication technique. When immersed in simulated body fluid (SBF) in vitro, the scaffolds released Cu ions into the medium at a rate that was dependent on the amount of Cu in the glass and simultaneously converted to hydroxyapatite (HA). At the concentrations used, the Cu in the glass was not cytotoxic to human bone marrow derived stem cells (hBMSCs) cultured on the scaffolds and the alkaline phosphatase activity of the hBMSCs increased with increasing Cu in the glass. When implanted in rat calvarial defects for 8 weeks, the scaffolds doped with 3 wt% CuO showed a significantly better capacity to stimulate angiogenesis and regenerate bone when compared to the undoped glass scaffolds. Together, these results indicate that the controlled delivery of Cu ions from borate bioactive glass implants is a promising approach in healing bone defects.

Bioceramic 3D Implants Produced by Laser Assisted Additive Manufacturing

Cranial defect restoration requires a suitable implant capable to fulfill protective and aesthetic functions, such as polymeric and metallic implants. Nevertheless, the former materials cannot provide osteointegration of the implant within the host bone nor implant resorption, which is also required in pediatricorthopedics for normal patient growth. Resorbable and osteoconductivebioceramics are employed, such as silicate bioactive glasses. Nevertheless, manufacturing based on conventional casting in graphite moulds is not effective for warped shape implants suitable for patient tailored treatments. In this work, we analyze the application of rapid prototyping based on laser cladding to manufacture bioactive glass implants for low load bearing bone restoration. This laser-assisted additive technique is capable to produce three-dimensional geometries tailored to patient, with reduced fabrication time and implant composition modification. The obtained samples were characterized; the relationships between the processing conditions and the measured features were studied, in addition to the biological behavior analysis.

The potential restorative effects of strontium-doped bioactive glass on bone microarchitecture after estrogen-deficieny induced osteoporosis: Physicochemical and histomorphometric analyses

Strontium (Sr) compounds have become increasingly popular in the field of osteoporosis treatment. However, the quality of new bone after implantation of strontium-containing bioceramics has yet to be investigated. In the present study, the newly formed bone tissue around strontium-doped bioactive glass (BG-Sr) implants was characterized. BG-Sr was implanted in the femoral condyl of ovariectomised rats (OVX). The resected bone was prepared for analysis using several physico-chemical and biological assays such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, and histomorphometry. BG-Sr biomaterial favored calcium phosphate layer integration on the surface of the glass and offered better bioactivity. Moreover, the histomorphometric analysis demonstrated that BV/TV, N. Ob were significantly higher in BG-Sr treated rats groups than those of BG groups. However, Ob. S/BS, and OV/BV were significantly lower in BG-Sr treated rats groups than those of BG groups. The (Oc.S/BS) was significantly decreased in BG-Sr groups, when compared with that of BG rat groups. On the other hand, the MS/BS had not significantly decreased in the BG-Sr treated rats groups when compared with that of BG groups, however; it was significantly higher when compared with control and OVX groups. These findings suggest that BG-Sr can be used as an inhibitory therapeutic potential of osteoporosis by delivering strontium to stimulate new bone remodeling.

Evaluation of borate bioactive glass scaffolds with different pore sizes in a rat subcutaneous implantation model

Borate bioactive glass has been shown to convert faster and more completely to hydroxyapatite and enhance new bone formation invivo when compared to silicate bioactive glass (such as 45S5 and 13-93 bioactive glass). In this work, the effects of the borate glass microstructure on its conversion to hydroxyapatite (HA) invitro and its ability to support tissue ingrowth in a rat subcutaneous implantation model were investigated. Bioactive borate glass scaffolds, designated 13-93B3, with a grid-like microstructure and pore widths of 300, 600, and 900 µm were prepared by a robocasting technique. The scaffolds were implanted subcutaneously for 4 weeks in Sprague Dawley rats. Silicate 13-93 glass scaffolds with the same microstructure were used as the control. The conversion of the scaffolds to HA was studied as a function of immersion time in a simulated body fluid. Histology and scanning electron microscopy were used to evaluate conversion of the bioactive glass implants to hydroxyapatite, as well as tissue ingrowth and blood vessel formation in the implants. The pore size of the scaffolds was found to have little effect on tissue infiltration and angiogenesis after the 4-week implantation.

Biocompatibility Analysis of Bioglass® 45S5 and Biosilicate® Implants in the Rabbit Eviscerated Socket

Purpose: Bioactive glass and bioactive glass-ceramic cone implants were placed in the rabbit eviscerated socket to assess their biocompatibility.Methods: Fifty-one Norfolk albino rabbits underwent evisceration of the right eye followed by implantation of cones made from Bioglass® 45S5 (control group) and two types of bioactive glass-ceramic (Biosilicate®), a single- and a two-phase bioactive glass-ceramic implants into the scleral cavity. Postoperative reactions, animal behavior and socket conditions were monitored daily. Clinical exam, biochemical evaluations, and orbit computed tomographic scan were done at 7, 90, and 180 days post-procedure. After that, the animals were euthanized, and the orbital content was removed and prepared to light microscopy with morphometric evaluation and scanning electron microscopy examination. Statistical analysis was done by parametric and non-parametric analysis of variance, complemented by Dunn’s and Tukey’s tests (p < 0.05).Results: All animals did not develop systemic toxicity throughout the experimental period and also did not have orbit infection, implant migration or extrusion. Morphological analysis demonstrated pseudocapsule around all implants. Bioglass® and single-phase Biosilicate® implants induced less inflammation and pseudocapsule formation than two-phase Biosilicate® cones. Seven days post-procedure, the inflammatory reaction was intense and gradually decreased throughout the experiment. Tissue reaction was least intense in animals receiving Bioglass® implants.Conclusions: We observe discrete differences among the studied materials, with best responses obtained with use of Bioglass® 45S5 and single-phase Biosilicate®. The authors agree these implants might be useful in the management of the anophthalmic socket.