Papers by Keyword: Simulated Body Fluid (SBF)

Abstract: Apatite nuclei were obtained by raising pH of an acellular simulated body fluid (SBF). The apatite nuclei and levothyroxine particles were dispersed in an ultrapure water and the apatite nuclei were attached to the surface of the levothyroxine particles. By soaking in SBF, apatite formation was induced by the apatite nuclei located on the surface of the levothyroxine particles and the levothyroxine particles were encapsulated with apatite. We evaluated release behavior of levothyroxine in phosphate buffered saline.

Abstract: A simple chemical conversion coating was adopted to deposit zinc calcium phosphate (ZCP) coating and strontium doped ZCP (SZCP) coating on AZ31 magnesium alloy to induce biocompatibility and reduce the degradation rate. The surface morphology, chemical composition and functional groups of the coating were characterized by Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy (SEM-EDS), X-Ray Diffraction (XRD) studies and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy respectively. SZCP coating formed at 20 min deposition time produced crack free surface with a high degree of crystallinity with barrier property, which ultimately retards the dissolution of magnesium in Simulated Body Fluid (SBF). The corrosion resistance of AZ31 magnesium alloy was improved by SZCP coating as evident from hydrogen evolution test (HET). Cytotoxicity evaluation with L969 cells showed that Sr doped ZCP coatings showed less toxicity on resorbable magnesium alloys.

Abstract: Magnesium alloys with their biodegradable characteristics can be a very good candidate to be used in biomedical implants. AZ91D magnesium alloy had been chosen for investigating the effect of gadolinium concentration on corrosion performance. AZ91D magnesium alloy was immersed in La (NO₃)₃, Mg (NO₃)₂, and Gd (NO₃)₃ in simulated body fluid (SBF) solution. The structure and formation mechanism of the coating are discussed in detail through surface morphology, corrosion rate and electrochemical test. The effects of gadolinium in different concentration on the corrosion performance of magnesium substrate are investigated.

Abstract: The influence of the addition element of Zn and Sr to degradation behavior of pure magnesium simulated body fluid (SBF) had been studied. The results indicate that the corrosion destroy on the surface of pure magnesium was reduced markedly through the addition element of Zn and Sr. The average corrosion rate of pure magnesium, Mg-1.0Zn and Mg-4.0Zn-1.0Sr alloy is 1.526 g/(m²•h), 1.337 g/(m²•h) and 1.163 g/(m²•h), respectively.

Abstract: The bioactive glasses 58S was first prepared using sol-gel technique and the 45S5 bioactive glass was prepared through melting method. The above bioactive glasses were then grounded into fine powders, and each of the glass powders and their mixtures was doped with the porogen in certain ratios respectively. The bioactive porous materials were finally produced through sintering. We investigated the microstructure, surface morphologies, bending strength and bioactivity of the porous materials via in vitro method combined with DTA, SEM and FTIR techniques. The results show that the porous material made from the 58S and 45S5 mixture possesses the best bioactivity and bio-mineralization function among all samples, thus is a very promising bioactive material for bone defects filling or bone tissue engineering scaffolds.

Abstract: Based on the unique redox property of electrically conductive polymers, Ca²⁺ was incorporated into polypyrrole (PPy) film that previously doped with polyelectrolyte heparin. Then the apatite-forming ability of the Ca²⁺-doped PPy was examined by a biomimetic method using stimulated body fluid (SBF), which has ion concentration nearly equal to those of human blood plasma. It was found that the Ca²⁺-doped PPy successfully formed bonelike apatite deposition on its surface after soaking in SBF for only 3 days, whereas the similar apatite deposition was formed on Ca²⁺-free PPy after soaking in SBF for 7 days. These indicated that the entrapment of Ca²⁺ into PPy could accelerate the formation of apatite deposition and the Ca²⁺-doped PPy was possessed of enhanced bioactivity. It is expected that the Ca²⁺-doped PPy would be a useful bioactive coating material of metallic medical devices or tissue engineering scaffolds to promote the bone tissue regeneration.

Abstract: We reported the apatite-forming ability of CaO-SiO₂ spherical particles obtained through a sol-gel processing. In this study, we synthesized the CaO-SiO₂ containing silver (Ag) ions using silver standard solution to induce antibacterial property and evaluated the effects of Ag on their apatite forming ability in a simulated body fluid (SBF). The particles with 30CaO·70SiO₂ starting composition in Ag standard solution with range 0 to 500 ppm Ag content were synthesized through the sol-gel processing. The prepared 30CaO·70SiO₂ could be obtained as spherical particles with regardless of Ag contents. The prepared Ag-contained 30CaO·70SiO₂ particles formed apatite on their surfaces after soaking in SBF regardless of Ag contents. Consequently, Ag-contained 30CaO·70SiO₂ spherical particle could be obtained without decrease of its apatite forming ability.

Abstract: In this study the formation of calcium phosphate phase via double diffusion method into a hydrogel matrix was investigated and its phase transformation in simulated body fluid was studied. White precipitate was formed within the hydrogel, due to the diffusion of calcium and phosphate ions through the hydrogel matrix in similar pH to human body. Phase composition, microstructure and structural groups in the composite samples were also characterized by X-Ray Diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infra-red (FTIR) analyses. Microstructure of precipitates formed within middle hydrogel, showed that detected materials are composed of carbonated hydroxyapatite and dicalcium phosphate dihydrate (DCPD, brushite). The particle size was about 10 nm .Analysis results showed that after incubation in simulated body fluid, dicalcium phosphate dehydrate phase transformed into crystalline hydroxy apatite.

Abstract: When pH or temperature of simulated body fluid (SBF) is raised, fine particles of calcium phosphate are precipitated. We found that this fine particle actively induces hydroxyapatite from body fluid or SBF and named the particle Apatite Nucleus (AN). In this study, we attached AN on the surface of γ-Fe₂O₃ nanoparticles and soaked them in SBF. By this treatment, hydroxyapatite was induced from AN and covered the whole surface of the γ-Fe₂O₃ nanoparticles, then hydroxyapatite microcapsule encapsulated γ-Fe₂O₃ was fabricated. We dispersed the microcapsules in urease solution, and collected the microcapsules by neodymium magnet. It was indicated that the urease was adsorbed to the hydroxyapatite microcapsules and collected by the magnetism of γ-Fe₂O₃ successfully.

Abstract: Bioactive Ti metal able to release Sr ions was prepared by chemical and heat treatments of Ti metal. Ti metal was initially soaked in 5M NaOH solution to form sodium hydrogen titanate. It was soaked in a mixed solution of CaCl₂ and SrCl₂ to replace its Na ions with Ca and Sr ions at a given range from 0.18 to 1.62 in Sr/Ca ratio. When it was heat-treated at 600 oC, it formed Sr-containing calcium titanate (SrCT) and rutile. The apatite formation in SBF of the treated metal was low, but increased markedly by subsequently soaking the metal in 1 M SrCl₂ solution at 80 oC. Thus, the treated metal gradually released Sr ions into phosphate-buffered saline up to 0.9 ppm. It is expected that the Ti metal formed with the bioactive SrCT layer could release Sr ions in a living body to promote bone formation, and bond to a living bone through an apatite.