Papers by Keyword: Carbonated Hydroxyapatite

Abstract: Microwave heating was used with a gas foaming method for fabricating limestone carbonated hydroxyapatite scaffold (SCHA). Carbonated hydroxyapatite (CHA) was produced from limestone as a calcium source using the co-precipitation method. For further treatment, 0.6 gr CHA powder was mixed in 1 ml H₂O₂ solution as a blowing agent. The slurry-foam-like CHA was heated in a microwave with different levels of heating power from 180 W to 720 W. The SCHA samples were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and Scanning electron microscope (SEM). The crystallinity and crystallite size were affected due to different rates of heating power in the microwave-assisted method. The increasing temperature decreased the crystallite size from 37.49 to 33.97(nm). However, other crystallinity trends were observed at 180 W because the lower power heating needed a longer time to be formed SCHA. The different power rates have an insignificant contribution to the morphology of the scaffolds.

Abstract: Carbonated hydroxyapatite (CHA), with a chemical composition close to the mineral found in human bone, represented higher solubility than stoichiometric hydroxyapatite (HA). Therefore, the B-type CHA is commonly used for bone tissue engineering. This study fabricated B-type CHA using Indonesian eggshells from chicken, organic chicken, and duck because of the high calcium carbonate (CaCO₃) content (94%). A co-precipitation method was used for synthesizing CHA. The physicochemical properties of the CHA were characterized using Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS), X-Ray Diffractometer (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Based on FTIR results for CHA, the stretching functional groups of B-type CO₃ were detected at 1452-1453 cm^-1, 1417-1418 cm^-1, and 873-874 cm^-1, which indicated the formation of B-type CHA. Meanwhile, CHA from organic chicken eggshells had low crystalline properties and the best morphology due to a more homogeneous and uniform agglomeration. More specifically, CHA based on organic chicken eggshells has a Ca/P molar ratio following natural human bone, which is 1.71. Therefore, all B-type CHA samples are candidates in bioceramic materials for bone tissue engineering applications.

Abstract: B-type carbonated hydroxyapatite (C_BHA) is potentially an excellent biodegradable bioceramic for bone repair. However, conventional sintering results in formation of undesired phases. Therefore, microwave sintering of C_BHA was investigated to assess the possibility to reduce formation of unwanted phases. Pellets with 0.8 mol% of B-type carbonate were sintered in a multimode instrumented cavity under static air with short thermal cycles. They were prepared from a C_BHA powder alone and from a mixture of C_BHA and carbon powder to generate a local in-situ CO₂ atmosphere. XRD, FT-IR, SEM and BET analyses indicated that C_BHA densification with increase temperature lead to decomposition into apatite. The addition of carbon powder to the C_BHA that generate a CO₂-rich atmosphere around the samples did not prevent the decomposition. Efficient control of temperature and atmosphere composition is required to improve microwave sintering of C_BHA bioceramics.

Abstract: The aim of this work is to investigate the influence of sintering temperature on purity and crystallography properties of carbonated hydroxyapatite (CHAp). The CHAp was synthesized using a coprecipitation method. The snail shells (Pilla ampulacea) were processed to yield calcium oxide as the calcium source in synthesis. The CHAp powder then was sintered for 2 h in an air atmosphere at 400, 600, 800, and 1000°C. An X-Ray diffractometer (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and energy dispersive x-ray (EDX) are used to investigate the physicochemical properties of CHAp. XRD, FTIR, and EDS results show primary phase is carbonated hydroxyapatite. Calcium oxide as a secondary phase is detected starting from 800°C. The crystallinity and crystallite size are increased along the increasing of sintering temperature. Drastic enhancement on these properties is shown at 600–800°C. However, there is no simple relation to the sintering temperature and lattice parameters. These results show that sintering temperature has an important role in the purity and crystallography properties of the CHAp.

Abstract: Carbonated hydroxyapatite (CHAp) is an inorganic mineral that more closely resembles the main component of composing human hard tissue in 2-8 wt% carbonate content. CHAp powders have been synthesized from oyster shells using the precipitation method. Oyster shells are one type of shellfish from the bivalve class which is rich in calcium carbonate content. In this research, CaO from oyster shells obtained from the decomposition process of CaCO₃ was used as a source of calcium and diammonium hydrogen phosphate and ammonium bicarbonate as well as a precursor of phosphate and carbonate, respectively. In addition, carbonate content variations were x = 0, 0.3, 0.8 and 1.2 which were characterized by fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and scanning electron microscope-energy dispersive X-Ray (SEM-EDX) to determine the functional groups, crystallographic properties, morphology and Ca/P molar ratio, respectively. Carbonate ion substitution in the hydroxyapatite crystal structure is known to decrease crystallinity and crystallite size. The theory is in accordance with the results obtained in this study with the crystallite size is 74.322, 46.933, 37.727, and 31.499 nm for 0.95, 2.7, 5.7, and 9.35 wt.% carbonate content, respectively.

Abstract: Three-dimensional (3D) porous carbonated hydroxyapatite (CHA) scaffolds were successfully prepared using polyurethane (PU) replication technique. Two sets of porous scaffolds were prepared using as-synthesized and as-calcined CHA powder as the main component of the slurry. The effect of the condition of starting material was investigated in terms of structure, phase purity, crystallinity and morphology of the fabricated porous scaffolds. Regardless of the condition of starting material used, the porous scaffolds fabricated was single phase B-type CHA and free of secondary phases. Interestingly, scaffolds made of as-calcined CHA powder (SC scaffolds) showed a smoother surface and more solidified struts when compared to as-synthesized CHA powder (SA scaffolds). This is attributed to the state of semi-crystalline phase of the as-calcined powder being amorphous phase. SC scaffold was found to be better scaffold with respect to handling, compaction strength and microstructure with better strut properties.

Abstract: Incorporation carbonate ion to hydroxyapatite (HAp) structure, known as carbonated hydroxyapatite (CHAp) is reported to reduce crystallinity, increase the solubility rate, and increase bioactivity. Sintered CHAp material is interesting because it may have a better biological response.CHAp derived from common cockle (Cerastoderma edule) shell have produced by precipitation method. This study aimed to investigate the effect of sintering temperature to compositon and crystal characteristics of CHAp. CHAp powder was sintered at 400, 600, and 800°C in air atmosphere.CHApas-preparedand sintered samples were analyzed using Energy Dispersive Spectrometry (EDS), Fourier Transform Infrared (FT-IR), and X-ray Diffractometer (XRD).EDS analysis showed that the Ca/P ratio of powder CHAp was around 1.67-1.94 (greater than the Ca/P ratioof HAp). For increasing of sintering temperature, carbonate and water content decreased, crystallinity and crystallite size increased.

Abstract: Carbonated Hydroxyapatite (CHAp) is hydroxyapatite (HAp) substituted with carbonate ions that are similar to natural bone inorganic constituents. CHAp based on abalone mussel shells (Halioitis asinina) with calcination temperature variations were successfully synthesized using the precipitation method. Abalone mussel shells powder was calcined at 650, 800 and 1000°C for 4 hours, that aimed to obtain calcium oxide (CaO) which has the best characteristics as a source of calcium (Ca) in the CHAp synthesis process. The effect of calcination temperature variations on the characteristics of abalone mussel shells powder was investigated and characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Energy Dispersive X-Ray Spectroscopy (EDX). In this study, calcination temperature variations affected the crystalline phase and the percentage of calcium (Ca) and carbonate (CO₃^2-) ions. The results of the characterization show that the calcination temperature at 1000°C is the optimum temperature to obtain CaO powder as a source of calcium (Ca) in CHAp synthesis.

Abstract: One of the major challenges in the development of scaffold for nerve regeneration is enhancing mechanical strength of the material to avoid the scaffold to rapidly degrade during regeneration process in nerve system. The aim of this study was to reveal the effect of freeze-thaw to the properties of gelatin-carbonated hydroxy apatite (CHA) membrane in two ratios 7 to 3 and 6 to 4 for gelatin to CHA respectively. Some variations of freeze-thaw cycles were applied for both ratios, which is referred for its biocompatibility in cells.The CHA was synthesized by wet precipitating method of calcium hydroxide and phosphoric acid in gelatin solution at room temperature and open system. The X-Ray Diffraction (XRD) and FTIR analysis was conducted to confirm the formation of type-B CHA in gelatin matrix. The resulted membrane was then subject for membrane characterization.It was known from the study that freeze-thaw treatment during membrane fabrication affects several properties of the membrane. Platelet loading capability decreased when freeze-thaw cycles increased. Meanwhile, the platelet was released more rapidly by freeze-thawed gelatin-CHA membrane compared to non-freeze-thawed one. The degradation percentage of the membrane decreased with the increasing freeze-thaw cycles, showing 4 hours slower degradation in the freeze-thawed membrane compared to the unfreeze-thawed one.Furthermore, it was observed that freeze-thaw improved the tensile strength of the membrane and the modulus elasticity increased simultaneously. Moreover, in general it was observed from this study that freeze-thaw treatment did not affect permeability of the membranes towards glucose transport.

Abstract: The hydroxyapatite (HA) is a biocompatible and bioactive biomaterial used as bone substitute, however, the high crystallinity of HA and consequently its low solubility may be a limitation for its clinical use. In order to improve the biosorption of HA, the partial substitutions in the chemical structure and doping with small amounts of impurities have been study. The objective of this study was to evaluate the biocompatibility of 3% Zinc-containing nanostructured carbonated hydroxyapatite (ZncHA) compared with the carbonated hydroxyapatite (cHA), both synthesized at 37°C and non-sintered, using as control the stoichiometric HA microspheres in subcutaneous of mice. The X-ray Diffraction (XRD) and Vibrational Spectroscopy in Infra Red Fourier Transform (FTIR) were used to characterize the biomaterials. In vivo test was performed in BALB/c mice by implanting of HA, cHA and ZncHA spheres in the subcutaneous tissue for 1, and 9 weeks (n=5). The negative control consisted in incision without material implantation (Sham group). The samples were histological processed to descriptive analysis of biological effect. The microscopic analysis showed a similar granulation reaction between groups at the first experimental period. In 9 weeks there was a time dependent biosorption of cHA compared with other groups. In conclusion, the biomaterials tested were biocompatible and cHA group showed a significant biosorption in comparison with HA and ZncHA groups. The doping of zinc did not influence the biocompatibility of biomaterial, however, change the biosorption response