The behaviour of selected yttrium containing bioactive glass microspheres in simulated body environments

The study aims at the manufacture and investigation of biodegradable glass microspheres incorporated with yttrium potentially useful for radionuclide therapy of cancer. The glass microspheres in the SiO₂–Na₂O–P₂O₅–CaO–K₂O–MgO system containing yttrium were prepared by conventional melting and flame spheroidization. The behaviour of the yttrium silicate glass microspheres was investigated under in vitro conditions using simulated body fluid (SBF) and Tris buffer solution (TBS), for different periods of time, according to half-life time of the Y-90. The local structure of the glasses and the effect of yttrium on the biodegradability process were evaluated by Fourier Transform Infrared (FT-IR) spectroscopy and Back Scattered Electron Imaging of Scanning Electron Microscopy (BEI-SEM) equipped with Energy Dispersive X-ray (EDX) analysis. UV–VIS spectrometry and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for analyzing the release behaviour of silica and yttrium in the two used solutions. The results indicate that the addition of yttrium to a bioactive glass increases its structural stability which therefore, induced a different behaviour of the glasses in simulated body environments.     

The effect of phosphate content on the bioactivity of soda-lime-phosphosilicate glasses

We report on the bioactivity of two series of glasses in the SiO₂–Na₂O–CaO–P₂O₅ system after immersion in simulated body fluid (SBF) after 21 days. The effect of P₂O₅ content was examined for compositions containing 0–9.25 mol.% phosphate. Both series of glasses degraded to basic pH, but the solutions tended towards to neutrality with increasing phosphate content; a result of the acidic phosphate buffering the effect of the alkali metal and alkaline earth ions on degradation. Bioactivity was assessed by the appearance of features in the X-ray diffraction (XRD) traces and Fourier transform infrared (FTIR) spectra consistent with crystalline hydroxyl-carbonate-apatite (HCAp): such as the appearance of the (002) Bragg reflection in XRD and splitting of the P–O stretching vibration around 550 cm^?1 in the FTIR respectively. All glasses formed HCAp in SBF over the time periods studied and the time for formation of this crystalline phase occurred more rapidly in both series as the phosphate contents were increased. For P₂O₅ content >3 mol.% both series exhibited highly crystalline apatite by 16 h immersion in SBF. This indicates that in the compositions studied, phosphate content is more important for bioactivity than network connectivity (NC) of the silicate phase and compositions showing rapid apatite formation are presented, superior to 45S5 Bioglass^® which was tested under identical conditions for comparison.     

Influence of strontium for calcium substitution on the glass–ceramic network and biomimetic behavior in the ternary system SiO<Subscript>2</Subscript>–CaO–MgO

Strontium (Sr) enhances bone formation both in vitro and in vivo, while it reduces bone resorption. Thus, Sr incorporation in bioactive glass–ceramic scaffolds for bone tissue regeneration could further enhance osteogenesis. The aim of this work was the synthesis, characterization and investigation of the apatite-forming ability in inorganic environment of two sol–gel-derived bioactive Sr-containing glass–ceramic materials with 5 and 10% of SrO. The thermal properties of the synthesized materials were studied using differential thermal analysis (TG–DTA). The apatite-forming ability test was conducted in SBF for various immersion times for both thermally treated and untreated samples. The characterization of the samples before and after immersion in SBF was performed with Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and scanning electron microscopy with associated energy-dispersive spectroscopy. FTIR spectra revealed that all synthesized glass–ceramic materials presented the characteristic bands of silicate glasses, while XRD identified various crystalline phases, mostly calcium silicates. Strontium is present in the form of strontium silicate in both as-received and thermally treated specimens, and Sr-diopside in the thermally treated specimens. The apatite-forming ability of the glass–ceramic materials was confirmed by the formation of a hydroxyapatite layer after 3 and 5 days of immersion in SBF on the surface of the untreated and thermally treated samples, respectively. The apatite layer, also, became thicker as the immersion time increased.     

Crystalline phase formation in metakaolinite geopolymers activated with NaOH and sodium silicate

The effect of the NaOH content and the presence of sodium silicate activators on the formation of crystalline phases from metakaolinite-based geopolymers were studied by X-ray powder diffraction (XRD), Rietveld quantitative XRD, solid-state MAS NMR and SEM in samples synthesized with varying NaOH contents and different curing times at 40 °C. Geopolymers activated with NaOH alone with Si/Na ratios of 4/4 or less formed the crystalline zeolite Na–A (Na₉₆Al₉₆Si₉₆O₃₈₄·216H₂O), but at ratios >4/4 nanosized crystals of another zeolite (Na₆[AlSiO₄]₆·4H₂O) were formed. The Si/Na ratio of 4/4 produces a product of greatest crystallinity. The addition of sodium silicate in addition to NaOH significantly reduces crystallite formation. The network units of all the materials containing NaOH and sodium silicate are essentially the same, namely, tetrahedral [SiO₄] units coordinated through four bridging oxygens to four aluminium atoms [denoted as Q⁴ Si(4Al) units]. A templating function of the various silicate units of the sodium silicate molecules is suggested to occur in geopolymerization, which differs from the reaction route operating when NaOH alone is used as the activator. This templating function is responsible for the suppression of crystallization and the increase in strength of the geopolymers activated with sodium silicate.     

Synthesis and characterization of manganese containing mesoporous bioactive glass nanoparticles for biomedical applications

Mesoporous bioactive glass (BG) nanoparticles based in the system: SiO₂–P₂O₅–CaO–MnO were synthesized via a modified Stöber process at various concentrations of Mn (0–7 mol %). The synthesized manganese-doped BG nanoparticles were characterized in terms of morphology, composition, in vitro bioactivity and antibacterial activity. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) analysis confirmed that the particles had spherical morphology (mean particle size: 110?nm) with disordered mesoporous structure. Energy dispersive X-ray spectroscopy (EDX) confirmed the presence of Mn, Ca, Si and P in the synthesized Mn-doped BG particles. Moreover, X-ray diffraction (XRD) analysis showed that Mn has been incorporated in the amorphous silica network (bioactive glass). Moreover, it was found that manganese-doped BG particles form apatite crystals upon immersion in simulated body fluid (SBF). Inductively coupled plasma atomic emission spectroscopy (ICP-OES) measurements confirmed that Mn is released in a sustained manner, which provided antibacterial effect against Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. The results indicate that the incorporation of Mn in the bioactive glass network is an effective strategy to develop novel multifunctional BG nanoparticles for bone tissue engineering.     

Study of yttrium containing bioactive glasses behaviour in simulated body fluid

The influence of yttrium oxide on the bioactivity of glasses in the system SiO₂-Na₂O-P₂O₅-CaO-B₂O₃-K₂O-MgO was studied in a simulated body fluid (SBF). Two series of glasses with different bioactivity were investigated. The reaction layers formed on the surface of the exposed glasses were evaluated by means of back scattered electron imaging of scanning electron microscopy equipped with energy dispersive X-ray analysis (BEI-SEM/EDXA). The concentration of Y, Ca and P released from the glasses into SBF, during 21 days was determined using inductively coupled plasma-emission spectroscopy ICP-AES and inductively coupled plasma-mass spectroscopy ICP-MS. Introducing yttrium in the selected bioactive glass tended to diminish the bioactivity of the glasses. The thickness of the calcium phosphate layer decreased with increasing yttrium oxide content. The same effect was also observed when yttrium oxide partially replaced only calcium, magnesium and phosphorous oxide in the precursor glass. The data show that we can produce bioactive glasses with yttrium oxide as a component. By suitable tailoring of the rest of the glasses the yttrium effect on the glass behavior in SBF should be possible to control and thus produce yttrium containing glasses with desired bioactivity.     

Synthesis,characterization and in vitro bioactivity of sol-gel-derived SiO2–CaO–P2O5–MgO bioglass

In this study, the synthesis of SiO₂–CaO–P₂O₅–MgO bioactive glass was performed by the sol-gel method. Sol-gel-derived bioglass material was produced both in powder and in discs form by uniaxial pressing, followed by sintering at 700 °C. The obtained material was evaluated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermal gravimetric analysis (TGA) and differential scanning caloremetry (DSC) analyses. The biocompatibility evaluation of the formed glass was assessed through in vitro cell culture [alkaline phosphatase (AP) activity of osteoblasts] experiments and immersion studies in simulated body fluid (SBF) for different time intervals while monitoring the pH changes and the concentration of calcium, phosphorus and magnesium in the SBF medium. The SEM, XRD and FTIR studies were conducted before and after soaking of the material in SBF. At first, an amorphous calcium phosphate was formed; after 7 days this surface consisted of deposited crystalline apatite. The present investigation also revealed that the sol-gel derived quaternary bioglass system has the ability to support the growth of human fetal osteoblastic cells (hFOB 1.19). Finally, this material proved to be non-toxic and compatible for the proposed work in segmental defects in the goat model in vivo.     

Synthesis,characterization and evaluation of bioactivity and antibacterial activity of quinary glass system (SiO2–CaO–P2O5–MgO–ZnO): In vitro study

Bioactive glasses in the systems SiO₂–CaO–P₂O₅–MgO (BGZn0) and SiO₂–CaO–P₂O₅–MgO–ZnO (BGZn5), were prepared by sol–gel method and then characterized. Surface reactivity was studied in simulated body fluid (SBF) to determine the effect of zinc (Zn) addition as a trace element. The effect of Zn addition to the glass matrix on the formation of apatite layer on the glass surface was investigated through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). Also, inductively coupled plasma–optical emission spectroscopy (ICP–sOES) was used to determine the concentrations of released ions in SBF solution after different time intervals in SBF solution. The antibacterial activity of Zn containing glass against Pseudomonas aeruginosa was measured by the halo zone test. The presence of Zn in glass composition improved chemical durability, slowed down the formation rate of Ca–P layer and decreased the size of crystalline apatite particles. Zn containing glass exhibited an excellent antibacterial activity against P. aeruginosa which could demonstrate its ability to treat bone infection.     

Novel Antibacterial and Bioactive Silicate Glass Nanoparticles for Biomedical Applications

In this work, the authors propose a new quick sol–gel procedure for bioglass nanoparticles production containing 10% mol of silver (AgBGs). These new AgBGs are characterized by Zeta potential analysis, scanning electron microscopy with X‐ray microanalysis (SEM/EDS), X‐ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and microbiological tests to confirm their bioactive and antibacterial properties. SEM shows that the average particle size is less than 200 nm and EDS confirms the successful incorporation of Ag₂O in the bioglass matrix. XRD confirms the amorphous nature of the AgBGs and, after SBF immersion, reveals their bioactive behavior with the presence of crystalline phase of calcium silicate and phosphorus oxide, which are also detected by FTIR analysis. FTIR also confirms the formation of typical siloxane bonds resulting from the condensation of silicate glass. Lastly, it is found that the developed AgBGs has an antibacterial effect against two different types of bacteria, thus demonstrating their ability to reduce the bacterial infection within 16 h.

     

Microwave energy-assisted formation of bioactive CaO–MgO–SiO<Subscript>2</Subscript> ternary glass from bio-wastes

Regeneration technique is extensively being sought after as a means of achieving bone repair without adverse immunological response. Silicate-based bioactive glasses containing Mg are gaining increasing attention for their biocompatibility. The current work has been focused on designing a facile and economic route using bio-wastes for synthesizing bioactive glasses in the CaO–MgO–SiO₂ system. Rice husk ash (RHA) obtained from burning rice husk was used as silica source, while Ca was extracted from eggshells for preparing the glass through a modified sol–gel approach. The gel formed was irradiated in microwave before sintering at 950^°C for 3 h. Thereafter, bioactivity test was conducted on the samples in simulated body fluid (SBF) at physiological conditions for a maximum of 14 days. Characterization of samples were performed before and after immersion in SBF to evaluate the composition, morphology and phases present in the glass using energy-dispersive X-ray analysis, scanning electron microscopy and X-ray diffraction. Apatite formation was confirmed using Fourier transform infrared spectroscopy. Results obtained showed the presence of diopside, wollastonite and pseudo-wollastonite as major bioactive phases. Hydroxyapatite formed on the material within 3 days in SBF, indicating good bioactivity.     

Fabrication and characterization of ZrO2–CaO–P2O5–Na2O–SiO2 bioactive glass ceramics

SiO₂–CaO–Na₂O–P₂O₅–ZrO₂ based bioactive glasses with different compositions of SiO₂ and yttrium stabilized ZrO₂ were prepared by the conventional melt quenching technique. The effects on the chemical–mechanical properties of bioactive glasses due to the addition of ZrO₂ by replacing SiO₂ were investigated. Microstructure and phase behavior were studied by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction analysis. Compressive strength, porosity, Vickers hardness, and Young’s modulus were measured as mechanical properties. Bioactivity and cell viability were investigated by immersion in simulated body fluid and MTT assay analysis. Osteosarcoma cell proliferation on the specimen surfaces was examined by confocal laser scanning microscopy. The results showed that replacing SiO₂ with ZrO₂ helps the bioactive glass to be completely vitrified at comparatively lower sintering temperature than conventional Bioglass^®. The mechanical properties were also improved without compromising biocompatibility. Bioactive glass containing 10 wt% ZrO₂ and 35 wt% SiO₂ showed compressive strength of 399.71 MPa, Young's modulus of 22.3 GPa, Vicker’s hardness of 502.54 HV, and porosity of 26 vol%.     

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.     

Synthesis of Si-substituted hydroxyapatite by a wet mechanochemical method

Si-substituted hydroxyapatites with up to 2.0 wt% Si content, have been prepared by a wet mechanochemical method to obtain improved biocompatibility. From XRD, ICP and FTIR analysis, single phase of modified hydroxyapatite with PO₄³⁻ partially substituted by SiO₄⁴⁻ was confirmed. The XRD data indicated that some changes take place in the HA lattice with varying Si contents in Si–HA samples. The in-vitro bioactivity of the as-obtained materials was determined by soaking the materials in SBF, monitoring the changes of chemical composition and pH value of the SBF solution, whereas the microstructures of the soaked powders were observed by TEM.     

Preparation and characterization of Li<Subscript>2</Subscript>O–CaO–Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–P<Subscript>2</Subscript>O<Subscript>5</Subscript>–SiO<Subscript>2</Subscript> glasses as bioactive material

The aim of the present investigation was to study the role of Al₂O₃ in the Li₂O–CaO–P₂O₅–SiO₂ bioactive glass for improving the bioactivity and other physico-mechanical properties of glass. A comparative study on structural and physico-mechanical properties and bioactivity of glasses were reported. The structural properties of glasses were investigated by X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy and the bioactivity of the glasses was evaluated by in vitro test in simulated body fluid (SBF). Density, compressive strength, Vickers hardness and ultrasonic wave velocity of glass samples were measured to investigate physical and mechanical properties. Results indicated that partial molar replacement of Li₂O by Al₂O₃ resulted in a significant increase in mechanical properties of glasses. In vitro studies of samples in SBF had shown that the pH of the solution increased after immersion of samples during the initial stage and then after reaching maxima it decreased with the increase in the immersion time. In vitro test in SBF indicated that the addition of Al₂O₃ up to 1.5 mol% resulted in an increase in bioactivity where as further addition of Al₂O₃ caused a decrease in bioactivity of the samples. The biocompatibility of these bioactive glass samples was studied using human osteoblast (MG-63) cell lines. The results obtained suggested that Li₂O–CaO–Al₂O₃–P₂O₅–SiO₂-based bioactive glasses containing alumina would be potential materials for biomedical applications.     

Characterisation of the bioactive behaviour of sol–gel hydroxyapatite–CaO and hydroxyapatite–CaO–bioactive glass composites

The fabrication and characterization of sol–gel derived hydroxyapatite–calcium oxide (HAp–CaO) material is investigated focusing on the effect of the addition of a bioactive glass on the material bioactive behaviour through the fabrication of a novel HAp–CaO (70 wt.%)–bioactive glass (30 wt.%) composite material. The bioactive behaviour of the materials was assessed by immersion studies in Simulated Body Fluid (SBF) and the alterations of the materials surfaces after soaking periods in SBF were characterized by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). A brittle and weakly crystalline carbonate hydroxyapatite (HCAp) layer was found to develop on the surface of all samples, few hours after immersion in SBF, confirming the high bioactivity of the material. Alterations of the morphology of the developed HCAp layer, which led to a more compact structure, were observed on the surface of composite samples after 7 days of immersion in SBF. The presence of the CaO phase seems to accelerate the formation of HCAp, while the bioactive glass affects both the morphology and cohesion of the developed layer.     

Sol–gel-derived manganese-releasing bioactive glass as a therapeutic approach for bone tissue engineering

Sol–gel processing allows the production of bioactive glasses (BG) with flexible compositions and the incorporation of different metallic ions with therapeutic benefits into the glass network. Manganese is among several previously studied therapeutically beneficial ions and has been shown to favour osteogenic differentiation, in addition to playing an important role in cell adhesion. The incorporation of Mn into bioactive glasses for tissue engineering has been previously conducted using the conventional melting route, whereas the sol–gel route has not yet been explored. Sol–gel technology has great versatility, allowing the preparation of BG with various compositions, sizes, morphologies and a large surface area that could provide improved cellular responses and enhanced bioactivity when compared to melt-derived glasses. In this context, this work developed new compositions of sol–gel bioactive glasses (on the SiO₂–P₂O₅–CaO–MnO system) and explored the effects of incorporating MnO on the structure, texture, in vitro bioactivity and cytocompatibility of these materials. Our results show that Mn-containing bioactive glasses present an amorphous character, high surface area and mesoporous structure. The formation of a hydroxycarbonate apatite (HCA) layer after immersion in simulated body fluid (SBF) revealed the high bioactivity of the glasses. Ion release evaluation indicated that the Si, Ca, P and Mn release levels could be adjusted within therapeutic limits, and cytotoxic analysis demonstrated that the ionic products of all samples generated a cell-friendly environment. Therefore, Mn incorporation into the bioactive glass network appears to be a potential strategy to develop superior materials with sustained ion release for tissue engineering.     

An investigation into the structure and reactivity of calcium-zinc-silicate ionomer glasses using MAS-NMR spectroscopy

The suitability of Glass Polyalkenoate Cements (GPCs) for orthopaedic applications is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of GPCs and its absence is likely to hinder cement formation. However, the authors have previously shown that aluminium-free GPCs may be formulated based on calcium zinc silicate glasses and these novel materials exhibit significant potential as hard tissue biomaterials. However there is no data available on the structure of these glasses. ²⁹Si MAS-NMR, differential thermal analysis (DTA), X-ray diffraction (XRD), and network crosslink density (CLD) calculations were used to characterize the structure of five calcium zinc silicate glasses and relate glass structure to reactivity. The results indicate that glasses capable of forming Zn-GPCs are predominantly Q₂/Q₃ in structure with corresponding network crosslink densities greater than 2. The correlation of CLD and MAS-NMR results indicate the primary role of zinc in these simple glass networks is as a network modifier and not an intermediate oxide; this fact will allow for more refined glass compositions, with less reactive structures, to be formulated in the future.     

Development of a composite based on hydroxyapatite and magnesium and zinc‐containing sol–gel-derived bioactive glass for bone substitute applications

In the present study, a bioceramic-based composite was prepared by sintering compacts made up of mixtures of hydroxyapatite (HA) and sol–gel-derived bioactive glass (64SiO₂-26CaO-5MgO-5ZnO) (based on mol%) powders. HA powder was mixed with different concentrations of the glass powders up to 30 wt.%. The effect of adding bioactive glass powder to HA matrix, on the mechanical properties of the composite was assessed by compression test. The specimen with the highest compressive strength was chosen to be immersed in simulated body fluid (SBF) to study apatite forming ability and dissolution behavior. It was found that compressive strength of the specimen was decreased 65% after maintaining in the SBF for 14 days. X-ray diffraction (XRD) showed prevalence of HA and β-TCP related peaks. Also, the surface morphology of the composite was observed using scanning electron microscopy (SEM). The study of degradation behavior revealed Si release capability of this composite. Biological evaluations in vitro confirmed the composite studied could induce osteoblast-like cells' activities.     

Conversion of melt-derived microfibrous borate (13-93B3) and silicate (45S5) bioactive glass in a simulated body fluid

Microfibrous bioactive glasses are showing a considerable capacity to heal soft tissue wounds, but little information is available on the mechanism of healing. In the present study, the conversion of microfibrous borate bioactive glass (diameter = 0.2–5 μm) with the composition designated 13-93B3 (5.5 Na₂O, 11.1 K₂O, 4.6 MgO, 18.5 CaO, 3.7 P₂O₅, 56.6 B₂O₃ wt%) was evaluated in vitro as a function of immersion time in a simulated body fluid (SBF) at 37 °C using structural and chemical techniques. Silicate 45S5glass microfibers (45 SiO₂, 24.5 Na₂O, 24.5 CaO, 6 P₂O₅ wt%) were also studied for comparison. Microfibrous 13-93B3 glass degraded almost completely and converted to a calcium phosphate material within 7–14 days in SBF, whereas >85 % of the silica remained in the 45S5 microfibers, forming a silica gel phase. An amorphous calcium phosphate (ACP) product that formed on the 13-93B3 microfibers crystallized at a slower rate to hydroxyapatite (HA) when compared to the ACP that formed on the 45S5 fibers. For immersion times >3 days, the 13-93B3 fibers released a higher concentration of Ca into the SBF than the 45S5 fibers. The fast and more complete degradation, slow crystallization of the ACP product, and higher concentration of dissolved Ca in SBF could contribute to the capacity of the microfibrous borate 13-93B3 glass to heal soft tissue wounds.     

Evaluation of the influence of albumin on the mineralization of a glass by Atomic Force Microscopy

Bioactive glasses have been used as a graft material that can stimulate the formation of a new bone. In vitro tests usually give sensible indications about the potential bioactivity of these glasses. In the present work the influence of egg albumin on the formation of a Ca-P precipitate on a glass of the system SiO₂-CaO-MgO-P₂O₅ was evaluated. The samples were immersed in simulated body fluid (SBF) that simulates the composition of human plasma, with and without albumin. After immersion in this solution for 7 and 14 days, the glass was characterized by X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM). AFM results of the samples after immersion in SBF with albumin show the development of a precipiate formed from the solution/substrate reaction. Glasses immersed in albumin-free SBF exhibit the formation of a thin layer easily detached from the substrate. XRD results indicate that the precipitate is essentially amorphous, evolving to octacalcium phosphate. As the formation of an adherent precipitate on the glass samples only occurred when the substrate was immersed in SBF with albumin, it is suggested that albumin improves the mineralization on the glasses.