scholarly journals Influence of strontium for calcium substitution in bioactive glasses on degradation, ion release and apatite formation

2011 ◽  
Vol 9 (70) ◽  
pp. 880-889 ◽  
Author(s):  
Yann C. Fredholm ◽  
Natalia Karpukhina ◽  
Delia S. Brauer ◽  
Julian R. Jones ◽  
Robert V. Law ◽  
...  
Keyword(s):  
Glass Network ◽  
Apatite Formation ◽  
Carbonate Apatite ◽  
Structure Property ◽  
Ion Release ◽  
Ph Change ◽  
Bioactive Glasses ◽  
Composition Structure

Bioactive glasses are able to bond to bone through the formation of hydroxy-carbonate apatite in body fluids while strontium (Sr)-releasing bioactive glasses are of interest for patients suffering from osteoporosis, as Sr was shown to increase bone formation both in vitro and in vivo . A melt-derived glass series (SiO 2 –P 2 O 5 –CaO–Na 2 O) with 0–100% of calcium (Ca) replaced by Sr on a molar base was prepared. pH change, ion release and apatite formation during immersion of glass powder in simulated body fluid and Tris buffer at 37°C over up to 8 h were investigated and showed that substituting Sr for Ca increased glass dissolution and ion release, an effect owing to an expansion of the glass network caused by the larger ionic radius of Sr ions compared with Ca. Sr release increased linearly with Sr substitution, and apatite formation was enhanced significantly in the fully Sr-substituted glass, which allowed for enhanced osteoblast attachment as well as proliferation and control of osteoblast and osteoclast activity as shown previously. Studying the composition–structure–property relationship in bioactive glasses enables us to successfully design next-generation biomaterials that combine the bone regenerative properties of bioactive glasses with the release of therapeutically active Sr ions.

scholarly journals Bioactive Glass and Silicate-Based Ceramic Coatings on Metallic Implants: Open Challenge or Outdated Topic?

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2929 ◽  
Author(s):  
Giulia Brunello ◽  
Hamada Elsayed ◽  
Lisa Biasetto
Keyword(s):  
Ceramic Coatings ◽  
Apatite Formation ◽  
Bioactive Glasses ◽  
Coating Materials ◽  
Bioactive Coatings ◽  
Metallic Implants ◽  
Speed Up

The overall success and long-term life of the medical implants are decisively based on the convenient osseointegration at the hosting tissue-implant interface. Therefore, various surface modifications and different coating approaches have been utilized to the implants to enhance the bone formation and speed up the interaction with the surrounding hosting tissues, thereby enabling the successful fixation of implants. In this review, we will briefly present the main metallic implants and discuss their biocompatibility and osseointegration ability depending on their chemical and mechanical properties. In addition, as the main goal of this review, we explore the main properties of bioactive glasses and silica-based ceramics that are used as coating materials for both orthopedic and dental implants. The current review provides an overview of these bioactive coatings, with a particular emphasis on deposition methods, coating adhesion to the substrates and apatite formation ability tested by immersion in Simulated Body Fluid (SBF). In vitro and in vivo performances in terms of biocompatibility, biodegradability and improved osseointegration are examined as well.

Fluoride-Containing Bioactive Glasses

2008 ◽  
Vol 39-40 ◽  
pp. 299-304 ◽  
Author(s):  
Delia S. Brauer ◽  
Natalia Karpukhina ◽  
Daphne Seah ◽  
Robert V. Law ◽  
Robert G. Hill
Keyword(s):  
Sodium Fluoride ◽  
Chemical Shifts ◽  
Glass Structure ◽  
Glass Network ◽  
The Body ◽  
Scanning Calorimetry ◽  
Bioactive Glasses ◽  
Living Bone

Fluoride is an important mineral for hard tissues in the body and appropriate fluoride exposure and usage are beneficial to bone and tooth integrity. Fluoride increases both bone density and bone mass due to stimulation of bone formation and it is used as a treatment for osteoporosis. Bioactive glasses have the capacity to form an intimate bond with living bone tissue due to formation of a mixed hydroxycarbonate apatite layer (HCA) in vitro and in vivo. This makes fluoride-containing bioactive glasses attractive biomaterials. In order to design fluoride-containing bioactive glasses, we need to understand the role of fluorine within the glass structure. A series of bioactive glasses with increasing fluoride content was prepared by a melt-quench route. Characterisation included differential scanning calorimetry (DSC), density measurements, MASNMR spectroscopy and studies in simulated body fluid (SBF). DSC results showed a linear decrease in glass transition temperature (Tg) with increasing amounts of fluoride. Density of the glasses increased with increasing amounts of fluoride. This may indicate an expansion of the silicate glass network accompanying incorporation of CaF2. 19F MAS-NMR spectroscopy showed broad peaks at chemical shifts between -135 and -120 ppm. As sodium fluoride gives a chemical shift of -223 ppm and calcium fluoride of -108 ppm, this indicated possible formation of mixed calcium sodium fluoride species. HCA and calcium phosphate layers were found on the glasses after one week of immersion in SBF showing the bioactivity of the glass series.

scholarly journals Influence of low amounts of zinc or magnesium substitution on ion release and apatite formation of Bioglass 45S5

2020 ◽  
Vol 31 (10) ◽  
Author(s):  
R. Wetzel ◽  
O. Bartzok ◽  
D. S. Brauer
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Apatite Formation ◽  
Zinc Ions ◽  
Ion Release ◽  
Bioactive Glasses ◽  
Particle Size Range ◽  
Low Concentrations ◽  
High Temperature Processing

Abstract Magnesium and zinc ions play various key roles in the human body, being involved, among others, in skeletal development and wound healing. Zinc is also known to have antimicrobial properties. While low concentrations can stimulate cells in vitro, high concentrations of magnesium or zinc introduced into bioactive glasses significantly reduce glass degradation and ion release and inhibit apatite precipitation. On the other hand, magnesium and zinc ions improve the high temperature processing of bioactive glasses, even when present at low concentrations only. Results here show that by substituting small amounts of Mg or Zn for Ca, ion release remains high enough to allow for apatite precipitation. In addition, magnesium and zinc containing bioactive glasses are shown to be very susceptible to changes in particle size and relative surface area. For a given magnesium or zinc content in the glass, ion release and apatite formation can be enhanced dramatically by reducing the particle size, reaching comparable levels as Bioglass 45S5 of the same particle size range. Taken together, these findings suggest that when introducing these ions into bioactive glasses, ideally low Mg or Zn for Ca substitution as well as small particle sizes are used. This way, bioactive glasses combining good high temperature processing with fast ion release and apatite precipitation can be obtained, providing the potential additional benefit of releasing magnesium or zinc ions in therapeutic concentrations.

Ion Release Behavior and Apatite-Forming Ability of Sol-Gel Derived 70S30C Bioactive Glass with Magnesium/Zinc Substitution

2011 ◽  
Vol 493-494 ◽  
pp. 55-60 ◽  
Author(s):  
A.Ansari Hamedani ◽  
F. Moztarzadeh ◽  
D. Bizari ◽  
M. Ashuri ◽  
M. Tahriri
Keyword(s):  
Tissue Engineering ◽  
Degradation Products ◽  
Calcium Phosphates ◽  
Sol Gel ◽  
The Body ◽  
Apatite Formation ◽  
Ion Release ◽  
Ph Change ◽  
Bioactive Glasses ◽  
Glass Powders

Bioactive glasses not only can bond to hard tissues of the body, are also able to release ions that have stimulatory effects on cells and so are regarded as promising candidate materials for gene activating purposes in tissue engineering applications. In this research the effect of co-substitution of Magnesium and Zinc for Calcium on bioactivity of binary sol-gel derived glass 70S30C (70 mol. % SiO2, 30 mol. % CaO) was investigated. Calcium phosphates forming ability tests and investigation of glass degradation products in simulated body fluid (SBF) were performed as follows.After sol-gel synthesis of glass powders of comparable and under 38 μm particle size distributions, their state of being amorphous was investigated using X-ray diffraction. Then for in vitro investigation of bioactivity, ion release, pH change and Calcium phosphate formation during immersion of glass powders in SBF at 37 ͦC up to 2 weeks were studied. Infrared spectroscopy was performed on the reacted glass powders.Results indicate that substitution of Zinc for Calcium suppresses crystalline apatite formation more effectively than substitution of Magnesium for Calcium and help us design modified compositions of magnesium and zinc containing bioactive glasses that can find applications in bone and also cartillage tissue engineering.

scholarly journals Composition-dependent in vitro apatite formation at mesoporous bioactive glass-surfaces quantified by solid-state NMR and powder XRD

RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86061-86071 ◽  
Author(s):  
Claudia Turdean-Ionescu ◽  
Baltzar Stevensson ◽  
Jekabs Grins ◽  
Isabel Izquierdo-Barba ◽  
Ana García ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Powder Xrd ◽  
Apatite Formation ◽  
Carbonate Apatite ◽  
Bioactive Glasses ◽  
Glass Surfaces ◽  
Mesoporous Bioactive Glass ◽  
Hydroxy Carbonate

Solid-state NMR and powder XRD are employed to quantify the ACP (amorphous calcium phosphate) and HCA (hydroxy-carbonate apatite) components grown from three mesoporous bioactive glasses with variable compositions.

scholarly journals The Influence of Na and Ti on theIn VitroDegradation and Bioactivity in 58S Sol-Gel Bioactive Glass

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Shirong Ni ◽  
Ruilin Du ◽  
Siyu Ni
Keyword(s):  
Activation Energy ◽  
Bioactive Glass ◽  
Body Fluid ◽  
Sol Gel ◽  
Apatite Formation ◽  
Ion Release ◽  
Buffer Solution ◽  
Bioactive Glasses ◽  
Initial Stage

The aim of this study was to investigate the effect of Na and Ti on thein vitrodegradation and bioactivity in the 58S bioactive glass. The degradation was evaluated through the activation energy of Si ion release from bioactive glasses and the weight loss of bioactive glasses in Tris-HCl buffer solution. Thein vitrobioactivity of the bioactive glasses was investigated by analysis of apatite-formation ability in the simulated body fluid (SBF). The results showed that Na in the 58S glass accelerated the dissolution rate of the glass, whereas Ti in the 58S glass slowed down the rate of glass solubility. Bioactivity tests showed that Na in glass increased the apatite-forming ability in SBF. In contrast, Ti in glass retards the apatite formation at the initial stage of SBF soaking but does not affect the growth of apatite after long periods of soaking.

scholarly journals Solvent Exposure and Ionic Condensation Drive Fuzzy Dimerization of Disordered Heterochromatin Protein Sequence

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 915
Author(s):  
Jazelli Mueterthies ◽  
Davit A. Potoyan
Keyword(s):  
Phase Separation ◽  
Low Complexity ◽  
Nuclear Bodies ◽  
Disordered Proteins ◽  
Solvent Exposure ◽  
Ion Release ◽  
Dimer Formation ◽  
Eukaryotic Organisms

Proteins with low complexity, disordered sequences are receiving increasing attention due to their central roles in the biogenesis and regulation of membraneless organelles. In eukaryotic organisms, a substantial fraction of disordered proteins reside in the nucleus, thereby facilitating the formation of nuclear bodies, nucleolus, and chromatin compartmentalization. The heterochromatin family of proteins (HP1) is an important player in driving the formation of gene silenced mesoscopic heterochromatin B compartments and pericentric regions. Recent experiments have shown that the HP1a sequence of Drosophila melanogaster can undergo liquid-liquid phase separation under both in vitro and in vivo conditions, induced by changes of the monovalent salt concentration. While the phase separation of HP1a is thought to be the mechanism underlying chromatin compartmentalization, the molecular level mechanistic picture of salt-driven phase separation of HP1a has remained poorly understood. The disordered hinge region of HP1a is seen as the driver of salt-induced condensation because of its charge enriched sequence and post-translational modifications. Here, we set out to decipher the mechanisms of salt-induced condensation of HP1a through a systematic study of salt-dependent conformations of single chains and fuzzy dimers of disordered HP1a hinge sequences. Using multiple independent all-atom simulations with and without enhanced sampling, we carry out detailed characterization of conformational ensembles of disordered HP1a chains under different ionic conditions using various polymeric and structural measures. We show that the mobile ion release, enhancement of local transient secondary structural elements, and side-chain exposure to solvent are robust trends that accompany fuzzy dimer formation. Furthermore, we find that salt-induced changes in the ensemble of conformations of HP1a disordered hinge sequence fine-tune the inter-chain vs. self-chain interactions in ways that favor fuzzy dimer formation under low salt conditions in the agreement with condensation trends seen in experiments.

scholarly journals Mesoporous Silica Nanoparticles and Mesoporous Bioactive Glasses for Wound Management: From Skin Regeneration to Cancer Therapy

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3337
Author(s):  
Sara Hooshmand ◽  
Sahar Mollazadeh ◽  
Negar Akrami ◽  
Mehrnoosh Ghanad ◽  
Ahmed El-Fiqi ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Skin Regeneration ◽  
Bioactive Molecules ◽  
Wound Management ◽  
Bioactive Glasses ◽  
Wide Range

Exploring new therapies for managing skin wounds is under progress and, in this regard, mesoporous silica nanoparticles (MSNs) and mesoporous bioactive glasses (MBGs) offer great opportunities in treating acute, chronic, and malignant wounds. In general, therapeutic effectiveness of both MSNs and MBGs in different formulations (fine powder, fibers, composites etc.) has been proved over all the four stages of normal wound healing including hemostasis, inflammation, proliferation, and remodeling. The main merits of these porous substances can be summarized as their excellent biocompatibility and the ability of loading and delivering a wide range of both hydrophobic and hydrophilic bioactive molecules and chemicals. In addition, doping with inorganic elements (e.g., Cu, Ga, and Ta) into MSNs and MBGs structure is a feasible and practical approach to prepare customized materials for improved skin regeneration. Nowadays, MSNs and MBGs could be utilized in the concept of targeted therapy of skin malignancies (e.g., melanoma) by grafting of specific ligands. Since potential effects of various parameters including the chemical composition, particle size/morphology, textural properties, and surface chemistry should be comprehensively determined via cellular in vitro and in vivo assays, it seems still too early to draw a conclusion on ultimate efficacy of MSNs and MBGs in skin regeneration. In this regard, there are some concerns over the final fate of MSNs and MBGs in the wound site plus optimal dosages for achieving the best outcomes that deserve careful investigation in the future.

In Vitro Degradation of β-TCP/PLLA Scaffolds with Different Proportions of β-TCP

2007 ◽  
Vol 336-338 ◽  
pp. 1545-1548
Author(s):  
Lin Luo ◽  
Guang Fu Yin ◽  
Yun Zhang ◽  
Ya Dong Yao ◽  
Wei Zhong Yang ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Porous Scaffolds ◽  
Carbonate Apatite ◽  
Tissue Formation ◽  
Cellular Attachment ◽  
Biodegradable Scaffolds ◽  
Scaffold Structure ◽  
Mechanical Strengths

Porous biodegradable scaffolds are widely used in bone tissue engineering to provide temporary templates for cellular attachment and matrix synthesis. Ideally, the degradation rate in vivo may be similar or slightly less than that of tissue formation, allowing for the maintenance of the scaffold structure and the mechanical support during early stages of tissue formation. Eventually, the 3-D spaces occupied by the porous scaffolds will be replaced by newly formed tissue. In this work, β-tricalcium phosphate/Poly-L lactide (β-TCP/PLLA) scaffolds with different proportions of β-TCP to PLLA were investigated. The effects of β-TCP proportions on degradation rate and mechanical strengths of the scaffolds were evaluated in simulated body fluid (SBF) at 37°C up to 42 days. Results show that: different proportions of β-TCP to PLLA have significant influence on degradation behaviors of the scaffolds, and mechanical strengths of the scaffolds with weight proportion of β-TCP to PLLA being 2 to 1 are much higher than those of the others during the degradation period. And in this period, the scaffolds biodegrade slowly, and Hydroxyl Carbonate Apatite (HCA) forms in the surface of the material.

scholarly journals Bone Regeneration by Novel Bioactive Glasses Containing Strontium and/or Magnesium: A Preliminary In-Vivo Study

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2223 ◽  
Author(s):  
Devis Bellucci ◽  
Valeria Cannillo ◽  
Alexandre Anesi ◽  
Roberta Salvatori ◽  
Luigi Chiarini ◽  
...  
Keyword(s):  
Statistical Significance ◽  
Formation Processes ◽  
Complete Dissolution ◽  
In Vitro Bioactivity ◽  
Bioactive Glasses ◽  
Beneficial Effects ◽  
Glass Dissolution

In this work, a set of novel bioactive glasses have been tested in vivo in an animal model. The new compositions, characterized by an exceptional thermal stability and high in vitro bioactivity, contain strontium and/or magnesium, whose biological benefits are well documented in the literature. To simulate a long-term implant and to study the effect of the complete dissolution of glasses, samples were implanted in the mid-shaft of rabbits’ femur and analyzed 60 days after the surgery; such samples were in undersized powder form. The statistical significance with respect to the type of bioactive glass was analyzed by Kruskal–Wallis test. The results show high levels of bone remodeling, several new bone formations containing granules of calcium phosphate (sometimes with amounts of strontium and/or magnesium), and the absence of adverse effects on bone processes due to the almost complete glass dissolution. In vivo results confirming the cell culture outcomes of a previous study highlighted that these novel bioglasses had osteostimulative effect without adverse skeletal reaction, thus indicating possible beneficial effects on bone formation processes. The presence of strontium in the glasses seems to be particularly interesting.

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