Papers by Keyword: Bioactivity

Abstract: In this research the results of the formation of composite materials based on magnesium for the needs of implant surgery are discussed. The synthesis of porous magnesium with the inclusion of hydroxyapatite particles was preformed by means of a powder metallurgical mechanochemical process. The resulting samples were impregnated with bioactive additives such as shilajit. To protect against premature corrosion, the samples were coated with plasma electrolytic oxidation (PEO).

Abstract: The present study investigated the phase composition, the structural, morphological, and bioactivity properties of silicon- and carbonate-doped biomimetic hydroxyapatite synthesized by precipitation from aqueous solutions in the presence of different amounts of citrate ions. The X-ray diffraction and Fourier transform infrared spectroscopy analyses confirmed that all the samples exhibited single-phase. Base on the results of the morphological study, all the obtained samples consisted of porous agglomerated particles made up of tiny crystallites in the nanometer range. The change in structural order, as well as the decrease in particle size and degree of crystallinity result from the presence of citrate ions were revealed by X-ray diffraction, dynamic light scattering, and scanning electron microscopy analyses. Bioactivity properties of samples were studied by analyzing their bioresorbability in physiological saline (ω (NaCl) = 0.9%) and evaluating their solubility in SBF solution after a certain period of soaking time. The amount of the released Ca²⁺ ions was found to increase with the increasing concentration of citrate ions introduced in the synthesis process. The better solubility of material with the presence of citrate ions was beneficial in the growth of apatite on its surface that made produced material more biocompatible.

Abstract: Bioactive glasses (BG) were applied in bone and dental applications as well as in tissue engineering. In this studies, a new bioglass 50S8P (50% SiO₂, 22% CaO, 20% Na₂O and 8% P₂O₅) with different aging time (3, 7, 10 and 15 days) was prepared by sol-gel method. These synthesized glasses were analyzed using X- ray powder diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The bioactivity of all BG is evaluated by incubating the BG powder in Hank's Balanced Salt Solution (HBSS) for 7, 14 and 21 days. Thermal analyses indicated the compositions can be stabilized at 700°C. XRD confirmed the primary crystalline phase was Na₄Ca₄Si₆O₁₈. Formation of silica network is established with the existence of functional group Si-O-Si (tetrahedral), confirmed with FTIR analyses. In vitro test confirm the apatite formation on the BG surface with characteristic of carbonate group (C-O) and P-O band noticed from FTIR and morphology of apatite formation on BG surface was observe using SEM

Abstract: Strontium (Sr) stimulates osteoblast and inhibits osteoclast activities in-vitro and is used clinically as a treatment for osteoporosis. In this research, the effect of Sr substitution on the apatite formation of sol-gel derived bioactive glass (BG) (55.90SiO₂-1.72P₂O₅ -21.67Na₂O - (20.69-x) CaO -x SrO) (x=0, 5 and 8 mol. %) were investigated. The synthesized Sr doped BG samples were treated in Hank's Balanced Salt Solution (HBSS) for 14 days to study the bioactivity. The achieved samples were evaluated by X-ray powder diffraction (XRD) and Scanning electron microscope (SEM). In XRD, the hydroxyapatite (HA) crystalline peak for 8% Sr-BG is less compared with others. When Sr amount is increased to 8%, the low crystalline peaks of HA were detected although the same soaking duration. FTIR spectra supported the delay precipitation of calcium phosphate (CaP), especially for the specimen containing 8% Sr. After 14 days soaking, SEM images confirmed the bioactivity of the synthesized samples by the formation of apatite on the glass surface.

Abstract: This paper presents the process and results of the formation of multifunctional materials based on magnesium for the needs of implant surgery. An integrated approach has been developed, including: (i) the synthesis of porous magnesium preforms by means of a powder metallurgical process; (ii) formation of composites based on synthesized nanoscale hydroxyapatite powder and magnesium metal powder by spark plasma sintering technology.

Abstract: Bioactivity is an important aspect in biomaterial science ensuring materials used are safe for clinical application. The study describes fabrication of composites containing polylactic acid (PLA) – polyethylene glycol (PEG) with incorporation of sol-gel derived 45S5 bioactive glass (BG). Thermal analysis via Differential Thermal Analysis shows a favorable point over degree of crystallization that influence cells attachment, although non-significant difference in values indicates BG has homogenously dispersed. This correlates to X-ray diffraction analysis where non-significant difference is seen in intensities of the diffraction peaks, which confirms low impact of BG brittleness properties over the fabricated composite. Composites’ pH and degradation study in Simulated Body Fluid shows a steady increment profile over time and lower degradation rate for the composite after incorporation of BG. In vitro cell proliferation study also showed that HDF cells seeded on composite film of P/BG2.5 exhibit highest cell viability with steady increment of proliferation throughout the observation period.

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: This paper highlights the detailed procedure for preparation of biocompatible sensors and transducers by CAD-CAM assisted investment casting (IC). Along with the properties such as biocompatibility and bioactivity, the presented materials possess good surface finish (required for aesthetic sense), acceptable dimensional accuracy (required for assembly purposes) and good surface hardness (required while chewing). In this paper efforts were made for improving surface hardness, finish, and dimensional accuracy of biocompatible materials by controlling composition/proportion of Ni and Cr in IC process. In this case study stir casting (SC) assisted Ni and Cr based metal matrix composites (MMC) has been prepared and composite prepared were poured in the investment mould. The result of study reveals that different material composition influenced the microstructure and the hardness of the MMC prepared. Further with change in weight percentage of Ni and Cr, different microstructures with particle clustering was observed. The employment of nickel and chromium composites for the fabrication of novel sensors and transducers is discussed.

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.