Papers by Keyword: Simulated Body Fluid (SBF)

Abstract: Abstract. Various bioactive calcium phosphates such as hydroxyapatite (HA) and carbonate apatite (CO₃Ap) have been widely studied due to their biocompatibility and osteoconductivity when implanted into bone defects. CO₃Ap has the ability to adapt bone structure and induce bone regeneration; so that it can be categorized as resorbable bioactive materials. CO₃Ap induced much stronger response such as cell adhesion and actin ring formation to osteoclast-like cells rather than HA. The aim of this study is to evaluate the bioactivity on zirconia (Y-TZP) coated with CO₃Ap using simulated body fluid (SBF). Twenty Y-TZP ZrO₂ disks with a 12-mm diameter and 1-mm thickness were employed as the samples. The disks were divided into two groups which the control group without CO₃Ap coating and tested group with CO₃Ap coating. Disks samples are dipped into CO₃Ap suspension for one minute and stored in 37°C incubator for 24 hours. The disks were soaked in SBF for 1, 4, and 7 day(s) at 36.5°C. The obtained apatite crystals were characterized by scanning electron microscopy (SEM). It was found that the apatite formation on the tested group was greater than the control group. The EDS pattern showed the presence of Ca and P on the control and tested group after SBF soaking, which indicate the apatite deposition on the disks’ surface. However, the Ca and P on the tested group was higher compared to the control group. The formation of apatite layer on the disks’ surface is bioactivity indicator of CO₃Ap.

Abstract: In this study, we aimed to introduce bioactivity to bioinert zirconia by performing sandblasting process and subsequently depositing apatite nuclei (AN), which are fine particles of calcium phosphate precipitated by raising pH of SBF, on the surface of the zirconia samples. By soaking the AN treated zirconia samples in SBF, hydroxyapatite formation was observed in 1 day and high hydroxyapatite-forming ability was attained.

Abstract: Ti-12Ta-9Nb-6Zr-3V-O alloy, one of the shape-memory alloys with lower Young’s modulus in comparison with conventional titanium alloy, was treated with sulfuric acid to form roughened surface on the substrate. In order to impart hydroxyapatite formation ability to the Ti-12Ta-9Nb-6Zr-3V-O alloy, apatite nuclei (AN) were precipitated on the roughened surface using simulated body fluid (SBF) adjusted at higher pH than physiological condition. By this treatment, AN-precipitated Ti-12Ta-9Nb-6Zr-3V-O alloy was obtained. The AN-precipitated Ti-12Ta-9Nb-6Zr-3V-O alloy showed high hydroxyapatite formation ability in physiological SBF.

Abstract: The aim of the present study was to characterize two kinds of TiN/TiO₂ coatings in terms of topography, composition, and electrochemical stability after immersion in simulated body fluid (SBF). Micropatterning of the substrate (Ti-5Al-4V alloy) was done by using electron beam modification (EBM) by scanning electron beam while nanostructured TiN/TiO₂ films were deposited over EBM Ti5Al4V substrates using two physical vapor deposition techniques: 1) magnetron sputtering, and 2) cathodic arc and glow-discharge methods. When immersed for 7 and 14 days in SBF at static conditions (37±0.05 °C, pH 7.4), Ca/P ratio of the apatite deposits increased from approximately 1.5 up to near stoichiometric (1.67), respectively. After the initial decrease, the pH of the solution during soaking increased gradually reaching values close to 7.7 for both coatings. However, the weight gain of the samples with Arc coatings after the immersion period in SBF was nearly three times more than those with magnetron deposited coating. The electrochemical potentiodynamic tests performed in SBF indicated a shift in the corrosion potentials towards nobler direction after 7 and 14 days of immersion compared to non-immersed samples, whereas the corrosion current density was slightly increased.

Abstract: In order to improve the anticorrosion ability of a Mg-5Zn-1.5Ca alloy used as a bone replacement material, this study prepared the MnCaP conversion coating, which was formed from a phosphating solution mixed with a MnCl₂ solution of 0.05 molarity, on a magnesium (Mg) alloy. After forming a MnCaP conversion coating on a Mg alloy, micro-arc oxidation (MAO) proceeded for improving the anticorrosion ability of the sample. As a result, when the 0.05MnCaP coating on a Mg alloy was immersed in the simulated body fluid (SBF), the corrosion current, pH value change, and hydrogen evolution volume of the SBF solution are lower than a uncoated Mg alloy. From the SEM and EDS analyses for a corroded 0.05MnCaP coating on a Mg alloy, the manganese (Mn) phosphate in a lumpy-rock form and the calcium (Ca) phosphate in a flake form alternate to each other densely, so that the coating can effectively prevent a Mg alloy from corrosion.

Abstract: When the pH or the temperature of a simulated body fluid is raised, fine particles of calcium phosphate are precipitated, which are named apatite nuclei (AN). In this study, we aimed to impart bioactivity to polycaprolactone by incorporating AN. AN-PCL composite films having different weight percentages of AN in PCL were fabricated by solution casting technique, using doctor blade method. Results showed that more than 20 wt.% AN-PCL films were fully covered with hydroxyapatite layer in three days soaking period in SBF.

Abstract: Spherical phosphorus–containing mesoporous silica (PMPS) particles were synthesized. In the PMPS particle preparation using the cationic surfactant (cetyltrimethylammonium bromide) as the template, the amphiphilic surfactant (Pluronic P123) and diethyl(2–bromoethyl)phosphonate were used for the particle shape control and the phosphorus source, respectively. Furthermore, we investigated the chemical reactions of the PMPS particles in simulated body fluid (SBF). By the phosphorus–containing, the hydroxyapatite formation and silicate ion dissolution ability on the PMPS particle surfaces were enhanced. These characteristic features will be useful for the biomedical applications such as bone formation.

Abstract: Particles of calcium phosphate were precipitated by raising the temperature and the pH of simulated body fluid (SBF) named Apatite Nuclei (AN). AN and polyvinylidene fluoride (PVDF) composites thin films with different weight percentages of AN in PVDF were fabricated by solution casting technique, using doctor blade method. In order to assess the bioactivity, the thin films were soaked in simulated body fluid (SBF). It was found that the film containing 30 wt.% of AN in PVDF actively induced hydroxyapatite formation in 3 days soaking period in SBF.

Abstract: In this study, a novel titania-supported spherical porous hydroxyapatite (sHAp + TiO₂) was prepared by compounding minute, uniquely shaped spherical porous hydroxyapatites (sHAp) with TiO₂. Adsorption of the representative protein bovine serum albumin (BSA) was evaluated and simulated body fluid immersion experiments were carried out. Minimal adsorption of BSA to TiO₂ was observed, and 33% and 25% adsorption to sHAp + TiO₂ and sHAp were observed, respectively. The reduction in BSA concentration observed in the sHAp and sHAp + TiO₂ solutions is presumably due to adsorption to HAp. It is highly likely that adsorption of the acidic protein BSA occurred at the sHAp Ca²⁺ site. In the simulated body fluid immersion experiments, there was greater expression of hydroxyapatite (HAp) on the surface of sHAp than there was on the surface of sHAp + TiO₂. In the case of TiO₂ alone, no HAp was produced, even after immersion for 3 days. These results suggest a relationship between BSA adsorption and the osteoconductivity of materials.

Abstract: The fabrication process of bioactive bearing grade PEEK was consisted of three steps. First, micropores were formed on the bearing grade PEEK plates by sulfuric acid treatment. Second, plates were exposed to O₂ plasma by glow discharge. Finally, the plates were immediately immersed in SBF controlled at pH 8.4 at 25.0 °C and held at 70 °C for 24 hours. By this final treatment, Apatite Nuclei were precipitated inside of the pores. In order to investigate which step has the most influence on enriching bioactivity, four types of samples were obtained by changing the combinations of each process and evaluated the bioactivity by using SBF.