Papers by Keyword: Hydroxyapatite (HA)

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Authors: Mamoru Aizawa, Yuki Chibu, Kohei Nagata, Toshiisa Konishi, Ken Ishii, Haruki Funao, Yoshiaki Toyama, Morio Matsumoto, Michiyo Honda
Abstract: Hydroxyapatite (HAp) is one of components of bone and teeth, and has an osteoconductivity. Thus, the HAp has been used as biomaterials for bone graftings. We have succeeded in development of the novel chelate-setting calcium-phosphate cement (CPC) using pure HAp particles surface-modified with inositol phosphate (IP6). While, biological apatite presented in bone and teeth of mammals contains various ions: Na+, K+, Mg2+, Cl-, F- and CO32-, in addition to Ca2+ and PO43- ions. In this work, in order to create the chelate-setting CPC with enhanced osteoconductivity, the above-mentioned biological apatite powder (hereafter, bone HAp), instead of pure HAp, was used as a starting powder for fabrication of the chelate-setting cement. The biocompatibility of the resulting chelate-setting bone HAp cement (hereafter, IP6-bone HAp cement) was examined using a rabbit’s tibia model. When the living reaction to hard tissue was histologically examined after 4 weeks implantation, we could observe that newly-formed bone directly bonded to the surface of the specimen. The newly-formed bone was also present around the cement specimen. The amounts of newly-formed bone around IP6-bone HAp cement was about 1.5 times those around IP6-pure HAp cement without bone minerals. The above findings demonstrate that the present IP6-bone HAp cements are one of the promising candidates as novel CPC with enhanced osteoconductivity.
Authors: Nor Suhaida Shahabudin, Zainal Arifin Ahmad, Norazharuddin Shah Abdullah
Abstract: It is arguable that successful bone tissue engineering (BTE) protocols relies heavily on scaffolds (i.e., for mechanical support, aid for 3D arrangement, allowing good nutrient and waste transport etc.). In this study, the consequence of adding a bentonite (B) layer between alumina foam (AF) and its hydroxyapatite (HA) coat scaffold is scrutinized by spatial characterization measurement (e.g., porosity, pore size, pore interconnectivity and compressive strength). Other than work on the said hydroxyapatite-bentonite coated alumina foam (HABCAF), spatial characterization efforts were also done for AF and HA coated AF (HACAF) scaffolds. Initially, AF scaffold was fabricated via the foam impregnation technique (FIT). Polyurethane (PU) foam was chosen as a template to ensure controlled porosity and guided pore interconnectivity within the resulting scaffold. HACAF and HABCAF are produced using AF scaffold skeleton, coated with HA and B (for HABCAF only) slurries of different viscosities. After drying and sintering stages, these scaffolds were tested. The results from composite coating show an increase of 40% in strength with the same pore size of PU foam. The HABCAF exhibited the highest compressive strength besides showing good interconnectivity and cell pores sizes (i.e., up to >500 μm). These results suggest that addition of B presents an interesting route in the making of good quality scaffolds for BTE applications.
Authors: S.S. Seyedmomeni, M. Naeimi, Majid Raz, J. Aghazadeh Mohandesi, F. Moztarzadeh
Abstract: Various kinds of bioactive materials are developed as bone substitutes. Bioactive materials may affect attachment, proliferation and differentiation of cells and the subsequent integration in a host tissue. In this research 21%CaO–5%P2O5–64%SiO2–5%ZnO-5%B2O3 and 16%CaO–5%P2O5–64%SiO2–5%ZnO-10%B2O3 bioactive glasses were successfully synthesized by the sol–gel technique. Then the prepared bioactive glasses were soaked into simulated body fluid. Then the prepared samples were characterized using X-ray diffraction (XRD) and Scanning electron microscopy (SEM). It was seen that addition of boron to the structure remarkably enhances the formation of hydroxyapatite on the surface of the bioactive glass and subsequently improves the bioactivity. The obtained results from SEM and XRD were in good agreement with each other. Besides, effect of boron on atomic arrangement of the prepared bioactive glass was studies and compared with previous researches. It was shown that by increasing the boron content, more crystalline domains would be observed.
Authors: Si Hua Wang, Zhi Gang Liu, Qiao Wang, Li Rong Yang, Feng Feng Li, Shou Wu Yu, Xiao Qing Liu, Peng Zhou, Xiao Xin Feng
Abstract: Luminescent Ln3+ (Ce3+, Tb3+) doped hydroxyapatite (HAp: Ce, Tb) phosphors were successfully fabricated via the modified hydrothermal process. The structure, morphology, and luminescent properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectra respectively. The XRD results reveal that the obtained HAp: Ce, Tb phosphors show the characteristic peaks of hydroxyapatite in a hexagonal lattice structure and the import of Ce3+and Tb3+ causes small change in the crystalline structure and leads to the peaks shifting and declining. It is observed that the as-prepared luminescent samples exhibit nearly equiaxial morphology of dispersed particles about 50-150 nm in size. Under 254 nm UV radiation excitation, the phosphors demonstrate the characteristic 5D47F36 emission lines of Tb3+and the excitation of Tb3+ is mainly caused by the energy transfer from Ce3+. PL intensity of Tb3+ doped HAp remarkably strengthened with increment of Ce3+ concentration and reached the maximum at the concentration of 4 mol%.
Authors: M.A. Sri Asliza, K. Mohd Zaheruddin, Azmi Rahmat, Shamsul Baharin Jamaludin, Rafezi Ahmad Khairel
Abstract: Ni deposited Hydroxyapatite powder was prepared by electroless deposition technique without sensitization and activation treatments. The composition and phase of deposition were studied. The surface morphologies and composition of initial pure HA powder, as received Ni deposited HA powder and compacted Ni deposited HA powder after sintering were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) respectively. The phases in the powder before and after sintering were investigated by x-ray diffraction (XRD). From the experiment, with the increase of reduction agent, the plating time becomes shorter and optimal concentration of reduction agent and powder ratio is 3:1. The result shows that Ni succesfully deposited on HA powder and confirmed by EDX result. The Ni grain size distribution of 75nm to 250nm can be clearly observed on the HA surface from the micrograph after sintering. Decomposition of hydroxyapatite into α-TCP (α tricalcium phosphate) and TTCP (tetracalcium phosphate) did not occur in nickel deposited HA before and after sintering. On the other hand, a sharp Ni peak were detected
Authors: Rusnah Mustaffa, Mohd Reusmaazran Mohd Yusof, Yusof Abdullah
Abstract: In Malaysia recently, it was found that cockle shell (Anadara granosa) is a potential source of biomaterial for bone repair. It is the most abundant sea species cultured in Malaysia. A possible advantage of using cockle shell as a biomaterial is that they may act as an antilog of calcium carbonate. Malaysian Nuclear Agency took this challenge to develop synthetic bone graft from natural cockle shell. To date, the artificial bone graft substitutes developed from hydroxyapatite (Ca10(PO4)6(OH)2) a bio ceramic is similar to the mineral constituent of human bone. The structure and the composition of hydroxyapatite (HA) are similar to the mineral phase of bone and, its bioactivity and biocompatibility makes it a preferred bone graft.
Authors: Chee Huan Leong, Andanastuti Muchtar, C.Y. Tan, Masfueh Razali
Abstract: Hydroxyapatite (HA) is a biomaterial with excellent biocompatibility. However, the brittleness and low fracture toughness of HA have limited its biomedical applications. As such, HA has been incorporated with zirconia (ZrO2) to enhance its mechanical strength. However, ZrO2 addition decreases the phase stability of HA. HA decomposition is not favored because it decreases the mechanical strength of HA/ZrO2. In this paper, the effect of sintering on HA decomposition is reviewed. Experimental results show that hot isostatic pressing of HA/ZrO2 is one of the most effective methods to suppress HA decomposition, yielding the highest relative density compared with other sintering methods.
Authors: Dwi Asmi
Abstract: In this study, bovine bone waste obtained from meatballs sellers was utilized as novel alternative bioresource of hydroxyapatite (HA). The femur bovine bone waste in bulk form was initially deproteinized using HCl and NaOH and then followed by calcination at 500 °C and 800 °C for 5 h to obtained HA powder. The thermal stability of HA powder was monitored using simultaneous thermogravimetric analysis (TG) and differential thermal analysis (DTA). The TG/DTA result shows that the combustion of the organic component of bone, especially of collagen occured at temperature range of 174-550 °C. The phase content, type of bond present, and morphology of calcined HA powder were conducted using x-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) respectively. The crystallinity of the HA sample shows increase with increasing of the temperature calcination. The characteristic of bands of HA and additionally peaks of carbonate ions were observed in the FTIR results and the morphologic characteristics of the HA particles shows the material is a homogeneous powder.
Authors: Lyudmila A. Rasskazova, Darya Lytkina, Yelena Shapovalova, Vladimir V. Botvin, Maksim A. Pozdnyakov, Ilya Zhuk, Anatoliy G. Filimoshkin, Natalya Korotchenko, Vladimir Kozik
Abstract: A new method in situ for producing of biocompatible composites based on hydroxyapatite and oligomers of lactic and glycolic acid is described. Their thermo-mechanical, physical-chemical and biological properties are studied as well. The formation of bonds between hydroxyapatite with lactic and glycolic oligomers in composites are confirmed by IR spectroscopy of the samples, including those obtained in the Soxhlet apparatus. The formation of calcium-phosphate layer on the composite's surface containing hydroxyapatite was shown by SBF-investigation. The scaffolds based on lactic acid oligomer do not stimulate formation of a calcium-phosphate layer and they are subjected to destruction by the way of hydrolysis.
Authors: Daniel Navarro da Rocha, Leila Rosa de Oliveira Cruz, Luciano de Andrade Gobbo, Marcelo Henrique Prado da Silva
Abstract: Hydroxyapatite is a bioceramic material of great interest for use as bone substitute because of its similarity with the composition of biological apatite. Cationic and anionic substitutions in the apatite structure have been made in order to optimize the synthesis and accelerate the process of bone repair. In the present study, niobate apatite was synthesized by a patented aqueous precipitation method. The bioactivity of the samples was assessed by X-ray diffraction analyses (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy with field emission gun (FEG-SEM; FEI Quanta FEG 250) in the samples before and after an incubation period in simulated body fluid. The results showed that after 3 days a bone-like apatite coating was formed onto the niobate apatite surface. A peculiar morphology comprised by nanosized wires was also observed on the niobate apatite surface.
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