Pub Date : 2017-09-26DOI: 10.1515/bglass-2017-0004
D. Möncke, R. Ehrt, D. Palles, I. Efthimiopoulos, E. Kamitsos, M. Johannes
Abstract An alkali niobate-silicate veneer ceramic for ZrO2-based dental restoration was developed and characterized for its physical properties and structure. The properties were adjusted for dental applications. The new lithium disilicate glass-ceramic VBK (sold as cerafusion or LiSi) can easily be applied by spray coating to any individually formed ZrO2-matrix and needs only one final tempering treatment. The surface of the glass-ceramic is very smooth. The color of the already translucent glass-ceramic can be adjusted to that of individual natural teeth. The structure of the glass-ceramicwas studied by XRD and Ramanspectroscopy as a function of heat-treatment and of spatial variations within the material and at its interfaces. ToF SIMS, SEM and thermal analysis techniques were applied to investigate the crystallization behavior and surface-interface reactions. XRD and Raman spectroscopy identified different crystalline phases in the amorphous glass matrix including Li2Si2O5, Li2SiO3, NaxLi(1−x)NbO3 and Na3NbO4. The Raman spectrum of the amorphous matrix is dominated by the vibrational activity of the highly polarizable niobate units with a prominent feature at 865 cm−1, assigned to Nb-O stretching in NbO6 octahedra, which have non-bridging oxygen atoms and are connected to the silicate matrix rather than to other niobate polyhedra.
{"title":"A multi technique study of a new lithium disilicate glass-ceramic spray-coated on ZrO2 substrate for dental restoration","authors":"D. Möncke, R. Ehrt, D. Palles, I. Efthimiopoulos, E. Kamitsos, M. Johannes","doi":"10.1515/bglass-2017-0004","DOIUrl":"https://doi.org/10.1515/bglass-2017-0004","url":null,"abstract":"Abstract An alkali niobate-silicate veneer ceramic for ZrO2-based dental restoration was developed and characterized for its physical properties and structure. The properties were adjusted for dental applications. The new lithium disilicate glass-ceramic VBK (sold as cerafusion or LiSi) can easily be applied by spray coating to any individually formed ZrO2-matrix and needs only one final tempering treatment. The surface of the glass-ceramic is very smooth. The color of the already translucent glass-ceramic can be adjusted to that of individual natural teeth. The structure of the glass-ceramicwas studied by XRD and Ramanspectroscopy as a function of heat-treatment and of spatial variations within the material and at its interfaces. ToF SIMS, SEM and thermal analysis techniques were applied to investigate the crystallization behavior and surface-interface reactions. XRD and Raman spectroscopy identified different crystalline phases in the amorphous glass matrix including Li2Si2O5, Li2SiO3, NaxLi(1−x)NbO3 and Na3NbO4. The Raman spectrum of the amorphous matrix is dominated by the vibrational activity of the highly polarizable niobate units with a prominent feature at 865 cm−1, assigned to Nb-O stretching in NbO6 octahedra, which have non-bridging oxygen atoms and are connected to the silicate matrix rather than to other niobate polyhedra.","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2017-0004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47273827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-08-28DOI: 10.1515/bglass-2017-0003
I. Saarenpää, P. Stoor, J. Frantzén
Abstract Bioactive glass (BAG) S53P4 granules represent a bone augmentation biomaterial for the surgical treatment of bony defects, even in challenging conditions such as osteomyelitis. The aim of this eight-week rabbit implantation study was to evaluate the biocompatibility and bone regeneration performance of a BAG S53P4 putty formulation following its implantation into the proximal tibia bone of twenty-eight New Zealand white rabbits. BAG S53P4 putty was compared to BAG S53P4 granules (0.5-0.8 mm) to evaluate whether the synthetic putty binder influences the bone regeneration of the osteostimulative granules. The putty formulation facilitates clinical use because of its mouldability, injectability and ease of mixing with autograft. Implantation of putty and granules into proximal tibia defects resulted in good osseointegration of the two groups. Both biomaterials were biocompatible, showed high new bone formation, high vascularization and periosteal growth. No signs of disturbed bone formation were observed due to the PEG-glycerol binder in the BAG S53P4 putty. Instead, intramedullary ossification and stromal cell reaction were more advanced in the putty group compared to the control group (p = 0.001 and p < 0.001). In conclusion, the novel mouldable BAG S53P4 putty showed reliable bone regeneration in bony defects without adverse tissue or cell reactions.
{"title":"BAG S53P4 putty as bone graft substitute – a rabbit model","authors":"I. Saarenpää, P. Stoor, J. Frantzén","doi":"10.1515/bglass-2017-0003","DOIUrl":"https://doi.org/10.1515/bglass-2017-0003","url":null,"abstract":"Abstract Bioactive glass (BAG) S53P4 granules represent a bone augmentation biomaterial for the surgical treatment of bony defects, even in challenging conditions such as osteomyelitis. The aim of this eight-week rabbit implantation study was to evaluate the biocompatibility and bone regeneration performance of a BAG S53P4 putty formulation following its implantation into the proximal tibia bone of twenty-eight New Zealand white rabbits. BAG S53P4 putty was compared to BAG S53P4 granules (0.5-0.8 mm) to evaluate whether the synthetic putty binder influences the bone regeneration of the osteostimulative granules. The putty formulation facilitates clinical use because of its mouldability, injectability and ease of mixing with autograft. Implantation of putty and granules into proximal tibia defects resulted in good osseointegration of the two groups. Both biomaterials were biocompatible, showed high new bone formation, high vascularization and periosteal growth. No signs of disturbed bone formation were observed due to the PEG-glycerol binder in the BAG S53P4 putty. Instead, intramedullary ossification and stromal cell reaction were more advanced in the putty group compared to the control group (p = 0.001 and p < 0.001). In conclusion, the novel mouldable BAG S53P4 putty showed reliable bone regeneration in bony defects without adverse tissue or cell reactions.","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2017-0003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48624714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-04-25DOI: 10.1515/bglass-2017-0002
K. O’Connell, U. Werner‐Zwanziger, H. O’Shea, D. Boyd
Abstract The effect of increasing substitutions of Ga2O3:Na2O on the structure and contingent properties, of six quaternary high borate glasses was evaluated. Component ion release and particularly gallium ion release was studied post extraction, under simulated physiological conditions. Increasing substitutions of Ga2O3:Na2O (i.e. 0:1 - 6:4) resulted in destabilization of the glass network, observed by increases in component ion release and half-life of release. However, at ≥ 6:4 Ga2O3:Na2O ratio, network stabilization appeared to occur, resulting in a decrease in ion release half-life and total ion release for B, Sr, and Ga at 720 h of extraction. A linear release profile for strontium was provided by each glass composition, and for gallium by composition GB202 (70B2O3-20SrO-6Na2O-4Ga2O3) and GB203 (70B2O3-20SrO-4Na2O-6Ga2O3) for up to 720 h. 11B MAS NMR reveals that the replacement of Na2O with Ga2O3 (in the studied composition range) causesa linear increase of three-fold coordinated B[3] groups at the expense of B[4] groups. The data indicates the potential formation of GaO4-tetrahedra, associated with network stabilization.
摘要评价了Ga2O3:Na2O取代量的增加对六种季铵高硼酸盐玻璃结构和相关性能的影响。在模拟生理条件下，对提取后的组分离子释放，特别是镓离子释放进行了研究。通过组分离子释放和释放半衰期的增加，Ga2O3:Na2O的取代增加（即0:1-6:4）导致玻璃网络的不稳定。然而，当Ga2O3:Na2O比例≥6:4时，网络稳定出现，导致B、Sr和Ga在提取720小时时的离子释放半衰期和总离子释放减少。每种玻璃组合物提供锶的线性释放曲线，组合物GB202（70B2O3-20SrO-6Na2O-4Ga2O3）和GB203（70B2O3-20SrO-4Na2O-6Ga2O3）提供镓的线性释放剖面长达720小时。11B MAS NMR显示，用Ga2O3取代Na2O（在所研究的组成范围内）导致三倍配位的B[3]基团线性增加，而牺牲了B[4]基团。该数据表明了与网络稳定相关的GaO4四面体的潜在形成。
{"title":"High Borate Networks as a Platform to Modulate Temporal Release of Therapeutic Metal Ions Gallium and Strontium","authors":"K. O’Connell, U. Werner‐Zwanziger, H. O’Shea, D. Boyd","doi":"10.1515/bglass-2017-0002","DOIUrl":"https://doi.org/10.1515/bglass-2017-0002","url":null,"abstract":"Abstract The effect of increasing substitutions of Ga2O3:Na2O on the structure and contingent properties, of six quaternary high borate glasses was evaluated. Component ion release and particularly gallium ion release was studied post extraction, under simulated physiological conditions. Increasing substitutions of Ga2O3:Na2O (i.e. 0:1 - 6:4) resulted in destabilization of the glass network, observed by increases in component ion release and half-life of release. However, at ≥ 6:4 Ga2O3:Na2O ratio, network stabilization appeared to occur, resulting in a decrease in ion release half-life and total ion release for B, Sr, and Ga at 720 h of extraction. A linear release profile for strontium was provided by each glass composition, and for gallium by composition GB202 (70B2O3-20SrO-6Na2O-4Ga2O3) and GB203 (70B2O3-20SrO-4Na2O-6Ga2O3) for up to 720 h. 11B MAS NMR reveals that the replacement of Na2O with Ga2O3 (in the studied composition range) causesa linear increase of three-fold coordinated B[3] groups at the expense of B[4] groups. The data indicates the potential formation of GaO4-tetrahedra, associated with network stabilization.","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2017-0002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44281320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-04-25DOI: 10.1515/bglass-2017-0001
F. Baino, E. Verné
Abstract Bioactive glasses, invented by Prof. Larry L. Hench in the late 1960s, have revolutionized the field of biomaterials as they were shown to tightly bond to both hard and soft living tissues and to stimulate cells towards a path of regeneration and self-repair. However, due to their relatively poor mechanical properties (brittleness, low bending strength and fracture toughness), they are generally unsuitable for load-bearing applications. On the other hand, bioactive glasses have been successfully applied as coatings on the surface of stronger/tougher substrates to combine adequate mechanical properties with high bioactivity and, in some cases, additional extrafunctionalities (e.g. antibacterial properties, drug release). After giving a short overview of the main issues concerning the fabrication of glass coatings, this review provides a state-of-the-art picture in the field and specifically discusses the development of bioactive and hierarchical coatings on 3D porous scaffolds, joint prostheses, metallic substrates (e.g. wires or nails) for orthopedic fixation, polymeric meshes and sutures for wound healing, ocular implants and percutaneous devices.
{"title":"Glass-based coatings on biomedical implants: a state-of-the-art review","authors":"F. Baino, E. Verné","doi":"10.1515/bglass-2017-0001","DOIUrl":"https://doi.org/10.1515/bglass-2017-0001","url":null,"abstract":"Abstract Bioactive glasses, invented by Prof. Larry L. Hench in the late 1960s, have revolutionized the field of biomaterials as they were shown to tightly bond to both hard and soft living tissues and to stimulate cells towards a path of regeneration and self-repair. However, due to their relatively poor mechanical properties (brittleness, low bending strength and fracture toughness), they are generally unsuitable for load-bearing applications. On the other hand, bioactive glasses have been successfully applied as coatings on the surface of stronger/tougher substrates to combine adequate mechanical properties with high bioactivity and, in some cases, additional extrafunctionalities (e.g. antibacterial properties, drug release). After giving a short overview of the main issues concerning the fabrication of glass coatings, this review provides a state-of-the-art picture in the field and specifically discusses the development of bioactive and hierarchical coatings on 3D porous scaffolds, joint prostheses, metallic substrates (e.g. wires or nails) for orthopedic fixation, polymeric meshes and sutures for wound healing, ocular implants and percutaneous devices.","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2017-0001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44593715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-14DOI: 10.1515/bglass-2016-0013
G. Bührer, Ulrike Rottensteiner, A. Hoppe, R. Detsch, Diana Dafinova, T. Fey, P. Greil, C. Weis, Justus P. Beier, Aldo R. Boccacini, R. Horch, A. Arkudas
Abstract effects of 3D scaffolds made from 45S5 bioactive glass (BG) doped with 1 wt. % copper ions in the arteriovenous loop model of the rat. Materials and Methods: An arteriovenous loop was built in the groin of 10 rats and inserted in 1% copper doped 45S5 BG scaffolds and fibrin. The scaffold and the AV loop were inserted in Teflon isolation chambers and explanted 3 weeks after implantation. Afterwards the scaffolds were analyzed by Micro-CT and histology regarding vascularization. Results were compared to plain 45S5 BG-based scaffolds from a previous study. Results: Micro-CT and histological evaluation showed consistent vascularization of the constructs. A tendency towards an increased vascularization in the copper doped BG group compared to plain BG constructs could be observed. However, therewas no significant difference in statistical analysis between both groups. Conclusions: This study shows results that support an increased angiogenetic effect of 1% copper doped 45S5 BG compared to regular 45S5 BG scaffolds in the rat arteriovenous loop model although these tendencies are not backed by statistical evidence. Maybe higher copper doses could lead to a statistically significant angiogenetic effect.
{"title":"Evaluation of in vivo angiogenetic effects of copper doped bioactive glass scaffolds in the AV loop model","authors":"G. Bührer, Ulrike Rottensteiner, A. Hoppe, R. Detsch, Diana Dafinova, T. Fey, P. Greil, C. Weis, Justus P. Beier, Aldo R. Boccacini, R. Horch, A. Arkudas","doi":"10.1515/bglass-2016-0013","DOIUrl":"https://doi.org/10.1515/bglass-2016-0013","url":null,"abstract":"Abstract effects of 3D scaffolds made from 45S5 bioactive glass (BG) doped with 1 wt. % copper ions in the arteriovenous loop model of the rat. Materials and Methods: An arteriovenous loop was built in the groin of 10 rats and inserted in 1% copper doped 45S5 BG scaffolds and fibrin. The scaffold and the AV loop were inserted in Teflon isolation chambers and explanted 3 weeks after implantation. Afterwards the scaffolds were analyzed by Micro-CT and histology regarding vascularization. Results were compared to plain 45S5 BG-based scaffolds from a previous study. Results: Micro-CT and histological evaluation showed consistent vascularization of the constructs. A tendency towards an increased vascularization in the copper doped BG group compared to plain BG constructs could be observed. However, therewas no significant difference in statistical analysis between both groups. Conclusions: This study shows results that support an increased angiogenetic effect of 1% copper doped 45S5 BG compared to regular 45S5 BG scaffolds in the rat arteriovenous loop model although these tendencies are not backed by statistical evidence. Maybe higher copper doses could lead to a statistically significant angiogenetic effect.","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2016-0013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67222512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-08-01DOI: 10.1515/bglass-2018-0008
F. Hmood, O. Goerke, Franziska Schmidt
Abstract Bioactive glass is an emerging research area for many scientists around the world. A large processing window combined with high bioactivity are anticipated features for such kind of glass. In fact, both features depend upon the glass network connectivity (NC). A good bioactive glass has a network that ensures a balance between the processing properties and the bioactivity. This study aims at developing a new chemical composition based on that of ICIE16 bioactive glass. Therefore, new compositions were investigated by introducing boron oxide and magnesium oxide with different molar ratios ranging from 1 to 3 mol% each to the composition of ICIE16; In addition,Na2O was partially replaced by P2O5. Melt-quenching technique was followed to prepare the bioactive glass. So far, the results have shown that the processing window increases with the proposed modifications. BP3 and BM2 bioactive glasses show the maximum processing window of a round 250 K. The relationship between the chemical composition and the processing window as well as the corresponding bioactivity will be hereafter discussed.
{"title":"Chemical Composition Refining of Bioactive Glass for Better Processing Features, Part I","authors":"F. Hmood, O. Goerke, Franziska Schmidt","doi":"10.1515/bglass-2018-0008","DOIUrl":"https://doi.org/10.1515/bglass-2018-0008","url":null,"abstract":"Abstract Bioactive glass is an emerging research area for many scientists around the world. A large processing window combined with high bioactivity are anticipated features for such kind of glass. In fact, both features depend upon the glass network connectivity (NC). A good bioactive glass has a network that ensures a balance between the processing properties and the bioactivity. This study aims at developing a new chemical composition based on that of ICIE16 bioactive glass. Therefore, new compositions were investigated by introducing boron oxide and magnesium oxide with different molar ratios ranging from 1 to 3 mol% each to the composition of ICIE16; In addition,Na2O was partially replaced by P2O5. Melt-quenching technique was followed to prepare the bioactive glass. So far, the results have shown that the processing window increases with the proposed modifications. BP3 and BM2 bioactive glasses show the maximum processing window of a round 250 K. The relationship between the chemical composition and the processing window as well as the corresponding bioactivity will be hereafter discussed.","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2018-0008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67222567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-04-13DOI: 10.1515/bglass-2016-0004
Susanne Heid, P. Stoessel, T. Tauböck, W. Stark, M. Zehnder, D. Mohn
Abstract Flame spray synthesis has opened the possibility to add additional elements to complex materials such as bioactive glasseswhile maintaining nanoparticulate properties. In this study, it was investigated whether a flamesprayed bismuth oxide doped nanometric 45S5 bioactive glass could be incorporated into a commercially available epoxy-resin root canal sealer, and how this compared to a conventional, pure 45S5 micrometric bioactive glass. Effects on radiopacity, microhardness, pH and mineral induction in phosphate buffered saline and simulated body fluid were studied. It was revealed that the radiopaque nanometric bismuth-containing 45S5 bioactive glass reduced radiopacity of the root canal sealer less than a conventional micrometric counterpart. In addition, pH induction and calcium phosphate precipitation were quicker with the nanometric compared to the micrometric material, whilst the micrometric glass displayed a higher alkaline capacity. Both materials apparently bound to the epoxy resin matrix, thus increasing its microhardness after polymerization reaction. Effects were dose-dependent. The investigated radiopaque bioactive glass containing bismuth oxide could be a valuable add-on for current root canal sealers.
{"title":"Incorporation of particulate bioactive glasses into a dental root canal sealer","authors":"Susanne Heid, P. Stoessel, T. Tauböck, W. Stark, M. Zehnder, D. Mohn","doi":"10.1515/bglass-2016-0004","DOIUrl":"https://doi.org/10.1515/bglass-2016-0004","url":null,"abstract":"Abstract Flame spray synthesis has opened the possibility to add additional elements to complex materials such as bioactive glasseswhile maintaining nanoparticulate properties. In this study, it was investigated whether a flamesprayed bismuth oxide doped nanometric 45S5 bioactive glass could be incorporated into a commercially available epoxy-resin root canal sealer, and how this compared to a conventional, pure 45S5 micrometric bioactive glass. Effects on radiopacity, microhardness, pH and mineral induction in phosphate buffered saline and simulated body fluid were studied. It was revealed that the radiopaque nanometric bismuth-containing 45S5 bioactive glass reduced radiopacity of the root canal sealer less than a conventional micrometric counterpart. In addition, pH induction and calcium phosphate precipitation were quicker with the nanometric compared to the micrometric material, whilst the micrometric glass displayed a higher alkaline capacity. Both materials apparently bound to the epoxy resin matrix, thus increasing its microhardness after polymerization reaction. Effects were dose-dependent. The investigated radiopaque bioactive glass containing bismuth oxide could be a valuable add-on for current root canal sealers.","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2016-0004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67221863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-04-11DOI: 10.1515/bglass-2016-0003
A. Pedone, Francesco Muniz-Miranda, A. Tilocca, M. Menziani
Abstract Molecular dynamics simulations of two glass nanoparticles with composition 25Na2O·25CaO 50SiO2 mol% (Ce-K NP) and 46.1SiO2·24.4Na2O·26.9CaO· 2.6P2O5 mol.% (Ce-BG NP) doped with 3.6 mol% of CeO2 have been carried out in order to explain the enhanced antioxidant properties of the former glass with respect to the latter. The present models show that the different catalase mimetic activity of the two NPs is related to the Ce3+/Ce4+ ratio exposed at their surface. In fact, this ratio is about 3.5 and 13 in the bulk and at the surface of the Ce-BG NP, and 1.0 and 2.1 in the bulk and at the surface of the Ce-K NPs, respectively. Since both oxidation states are necessary for the catalysis of the dismutation reaction of hydrogen peroxides, NPs with a very high Ce3+/Ce4+ ratio possess poorer antioxidant properties. Moreover, our simulations reveal that the already low silicate connectivity found in the bulk glasses examined here is further reduced on the nanoparticle surface, whereas the Na+/Ca2+ ratio rapidly increases. Sodium, calcium and cerium sites in proximity of the surface are found to be under-coordinated, prone to quickly react with water present in physiological environments, thus accelerating the glass biodegradation
{"title":"The antioxidant properties of Ce-containing bioactive glass nanoparticles explained by Molecular Dynamics simulations","authors":"A. Pedone, Francesco Muniz-Miranda, A. Tilocca, M. Menziani","doi":"10.1515/bglass-2016-0003","DOIUrl":"https://doi.org/10.1515/bglass-2016-0003","url":null,"abstract":"Abstract Molecular dynamics simulations of two glass nanoparticles with composition 25Na2O·25CaO 50SiO2 mol% (Ce-K NP) and 46.1SiO2·24.4Na2O·26.9CaO· 2.6P2O5 mol.% (Ce-BG NP) doped with 3.6 mol% of CeO2 have been carried out in order to explain the enhanced antioxidant properties of the former glass with respect to the latter. The present models show that the different catalase mimetic activity of the two NPs is related to the Ce3+/Ce4+ ratio exposed at their surface. In fact, this ratio is about 3.5 and 13 in the bulk and at the surface of the Ce-BG NP, and 1.0 and 2.1 in the bulk and at the surface of the Ce-K NPs, respectively. Since both oxidation states are necessary for the catalysis of the dismutation reaction of hydrogen peroxides, NPs with a very high Ce3+/Ce4+ ratio possess poorer antioxidant properties. Moreover, our simulations reveal that the already low silicate connectivity found in the bulk glasses examined here is further reduced on the nanoparticle surface, whereas the Na+/Ca2+ ratio rapidly increases. Sodium, calcium and cerium sites in proximity of the surface are found to be under-coordinated, prone to quickly react with water present in physiological environments, thus accelerating the glass biodegradation","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2016-0003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67221765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-03-10DOI: 10.1515/bglass-2016-0002
S. Omar, J. Pastore, A. Bouchet, S. Pellice, V. Ballarin, S. Cere, J. Ballarre
Abstract AISI 316L stainless steel is commonly used as a low-cost material for permanent implants. It can be protected for degradation and corrosion by applying a hybrid silica based coating. Also the bioactive response of the implant can only be achieved by functionalizing the coated implant surface. The aim of this work is to synthesize and characterize a sol-gel made glass particles from the system SiO2-CaO-P2O5 with potential as bone inductive material, with and without an aging treatment of the precursor solution. The glass was synthesized by sol-gel technique that, comparing with melt glasses, generates an open net structure that could lead to particle dissolution and apatite deposition for biological purposes. The synthesized glass is dispersed by spray onto AISI 316L protected by a hybrid silica based coating, generating deposits with different size and morphology. To characterize the particles composition, microRaman spectroscopy was applied. It showed that no significant changes were reached after aging or thermal treatment of the deposited particles. Image processing techniques based on Mathematical Morphology were used to analyze morphology and sizes of the deposits obtain with the different sols (aged and no aged). Aproximately 50% of the surface was covered with particles made with a glass aged, and a 25% of covered area was reached with no aged one. When no aged glass particles were deposited, the particle size distribution shows the presence of many big particles with a roundness factor between 0.8 and 1 in a high percentage, meaning that they are spherical due to the presence of solvent and with a more open glass structure in the no aged glass. The Digital Image Processing and Raman spectroscopy tools help to analyze, characterize and quantify the bioactive particles deposited onto coated surgical grade stainless steel in terms of morphology, distribution and composition.
{"title":"SiO2-CaO-P2O5 (58S) sol gel glass applied onto surgical grade stainless steel by spray technique: morphological characterization by digital image processing","authors":"S. Omar, J. Pastore, A. Bouchet, S. Pellice, V. Ballarin, S. Cere, J. Ballarre","doi":"10.1515/bglass-2016-0002","DOIUrl":"https://doi.org/10.1515/bglass-2016-0002","url":null,"abstract":"Abstract AISI 316L stainless steel is commonly used as a low-cost material for permanent implants. It can be protected for degradation and corrosion by applying a hybrid silica based coating. Also the bioactive response of the implant can only be achieved by functionalizing the coated implant surface. The aim of this work is to synthesize and characterize a sol-gel made glass particles from the system SiO2-CaO-P2O5 with potential as bone inductive material, with and without an aging treatment of the precursor solution. The glass was synthesized by sol-gel technique that, comparing with melt glasses, generates an open net structure that could lead to particle dissolution and apatite deposition for biological purposes. The synthesized glass is dispersed by spray onto AISI 316L protected by a hybrid silica based coating, generating deposits with different size and morphology. To characterize the particles composition, microRaman spectroscopy was applied. It showed that no significant changes were reached after aging or thermal treatment of the deposited particles. Image processing techniques based on Mathematical Morphology were used to analyze morphology and sizes of the deposits obtain with the different sols (aged and no aged). Aproximately 50% of the surface was covered with particles made with a glass aged, and a 25% of covered area was reached with no aged one. When no aged glass particles were deposited, the particle size distribution shows the presence of many big particles with a roundness factor between 0.8 and 1 in a high percentage, meaning that they are spherical due to the presence of solvent and with a more open glass structure in the no aged glass. The Digital Image Processing and Raman spectroscopy tools help to analyze, characterize and quantify the bioactive particles deposited onto coated surgical grade stainless steel in terms of morphology, distribution and composition.","PeriodicalId":37354,"journal":{"name":"Biomedical Glasses","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bglass-2016-0002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67222072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-28DOI: 10.1515/bglass-2016-0005
Ambuj Mishra, J. Rocherullé, J. Massera
Abstract Ag doped-bioactive phosphate glasses were processed by traditional melt quenching technique with the concentration of Ag2O ranging from 0 to 5 mol%. The Ag doping led to the depolymerization of the phosphate networkwhich is accompanied by a decrease in the glass transition temperature. The processing window represented by ∆T (∆T=Tx-Tg) exhibited a maximum for glasses containing 2-3 mol% of Ag2O. An increase in Ag content induced an increase in the glass dissolution rate. The precipitation of a Sr-CaP layer at the surface of the glass particulates was found to occur at shorter immersion time for the Ag containing glasses. The congruent dissolution and wide processing window of these Ag containing glasses may be of great interest for scaffold manufacturing from sintering of glass powders with antimicrobial properties.
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