Papers by Keyword: β-TCP

Abstract: This research has studied the addition effect of woven carbon fiber treated with NaOH and coated by β- TCP to the conventional polymethyl methacrylate (PMMA). Two stages are involved in the preparation of heat-cured acrylic denture composite. The first chemical treatment of woven carbon fiber (WCF) surface by different concentrations of NaOH (0.10, 0.15, and 0.20 M) and coating carbon fiber with β-TCP by various weight fractions (0.08, 0.10, and 0.12 wi) were carried out. The second stage includes the reinforcement of denture base material by treated and coated WCF. The functional groups of the WCF surface before and after alkali treatment were studied by FTIR. The morphology of the WCF surface before and after alkali treatment was observed by FESEM, the diameter of pores on the untreated and treated fibers, and the adhesion of β-TCP powder to the fiber was also observed. Mechanical tests include: impact strength (I.S.) and flexural strength (F.S) were calculated using a three-point bending test with a universal test machine and a Charpy impact test machine, respectively. From the result, reinforcing PMMA with treated and coated WCF improves the mechanical properties (impact and flexural strength).

Abstract: Being one of the three elements of tissue engineering, three-dimensional porous structure scaffold plays an important role in tissue engineering. As it not only prvovide cells for the life, but also serves as a template to guide tissue regeneration and control of organizational structure and other functions. In this study, hyaluronic acid and gelatin are successfully cross-linked by 1-ethyl- (3-dimethylaminopropyl) -carbodiimide hydrochloride (EDC) , and compound β-TCP microspheres to prepare porous hydrogel scaffolds. The microspheres were analyzed by X-ray diffraction (XRD). The scaffolds were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). At the same time, the compressive strength, swelling ratio, degradation of the scaffold were tested. To assess the in vitro cell compatibility of the scaffolds, mouse L929 fibroblasts were seeded onto scaffolds for cell morphology and cell viability studies. The results showed that the pore size of the porous scaffold can be adjusted by changing the ratio of gelatin to hyaluronic acid (HA), increasing the proportion of hyaluronic acid in a certain range, pore size will be significantly increased. With the increase of the proportion of hyaluronic acid in the scaffold, the swelling ratio and the degradation rate also increased. The compressive strength of the scaffold increased with the increase of the proportion of gelatin. The appropriate ratio of β-TCP can promote cell growth and proliferation.

Abstract: Mesoporous silica (MPS) coatings on β-tricalcium phosphate (β-TCP) granules and their protein adsorptive capabilities were studied. β-TCP granules containing 2 wt% of aluminum oxide and 6 wt% of silicon oxide were prepared using a pan-type granulator and heated at 1200 oC. MPS coatings on β-TCP granules was carried out by a dip-coating method, but the β-TCP granules were not covered by the MPS particles. A silica interlayer was formed on the β-TCP granules via magnetron sputtering prior to the coating of the MPS. The β-TCP granules coated with the silica interlayer were fully covered by the MPS particles. A silica interlayer may offer bonding between the β-TCP granules and MPS coating. The adsorption of protein on the MPS-coated β-TCP granules was evaluated by UV-VIS spectroscopy. The adsorption capacity of protein on the β-TCP granules was improved by the MPS coatings on the β-TCP granules, and that of the β-TCP granules coated with the silica interlayer showed a higher protein adsorption capacity.

Abstract: Porous Hyaluronan/β-tricalcium phosphate composite scaffolds were synthesized through lyophilizing and subsequent heterogeneous crosslinking method. The morphology of the composite scaffolds were investigated by scanning electron microscopy (SEM). The swelling behavior, mechanical property, degradation behavior and cell adhesion ability of samples were also studied. The results revealed that hyaluronan mainly contributed to the polymer matrix and water adsorption, whereas β-TCP acted as a reinforcement to strengthen the porous structure, while too much β-TCP would make the structure collapse. The pose size of obtained scaffolds ranges from100μm to 200μm and the porosity decreased with the increase of β-TCP content. The degradation behavior and cell adhesion test indicated that increasing hyaluronan concentration can effectively improve the degradability of scaffolds and the incorporation of β-TCP improved the cell adhesion performance. Thus a simple way to prepare hyaluronan-based composite scaffolds was provided, which could be potentially used as an tissue engineering material.

Abstract: Synthetic materials based on calcium such as hydroxyapatite and beta-TCP are one of the main bone substitutes because of their biocompatibility. The starch consolidation is a simple and low cost technique which is based on using the starch as a gel former in the presence of water, turning possible its use as a conforming and main element to form pores. In this project,samples were produced trough starch conformation by fixing the percentage of solids (beta-TCP) in 50% and varying the amount and type of starch (corn and potato) in 10, 20, 30 and 40%. The results showed that it was possible to obtain porous samples by using corn and potato starches. Moreover, the percentage of starch added strongly influenced porosity and resistance of the samples. The addition of 30% or more of starch reduced the mechanical resistance of samples which limited their use.

Abstract: Bio-absorbable materials have been strongly needed in bone regenerative surgery. β-TCP ceramics have been widely used as bone tissue scaffold materials, due to their bio-compatibility and bio-degradation. The aims of this study are to estimate blood permeation into different porous β-TCP blocks (75% and 67% in porosity), and to evaluate the behaviors of the 75% porous β-TCP block in rat subcutaneous tissue and sheep iliac bone defect by histological observation and 3-dimensional (3D) imaging analysis by μ-CT. The 75% β-TCP block revealed better performance in blood permeation than the 67% β-TCP in a dish including 3ml of sheep blood at 2 and 10 minutes. Almost area of the 75% β-TCP block turned to red at 10 minutes. In rat subcutaneous tissue, the bulk region of the 75% β-TCP was stained with HE. TRAP-positive multinucleated giant cells appeared on the surface of bulk at 4 weeks. In sheep iliac bone defect (10×15×9 mm³) model, μ-CT showed bone ingrowth into almost pores of the 75% β-TCP block at 2 months, and the block was absorbed and replaced by new bone until 4 months. The block was reduced to one-third in horizontal length and from 10 mm to 4 mm in vertical length at 2 months by 3D images. Body fluid stained by HE was found in the bulk region. We believe the body fluid permeation inside the bulk of the 75% porous β-TCP should contribute to the initial cell adhesion, proliferation and differentiation, and its biodegradation. It was concluded that the super porous β-TCP block with hydrophilic property might be a biological scaffold, harmonized with bone remodeling.

Abstract: The cause of the degradation was analyzed by applying the highly humid conditions during the storage of cement composed of β-tricalcium phosphate (β-TCP) and monocalcium phosphate monohydrate (MCPM). For the β-TCP and MCPM stored separately under the humid environment, the mild increase in the setting time was observed, and the product after the setting was entirely dicalcium phosphate dihydrate (CaHPO₄2H₂O: DCPD). However, for the β-TCP and MCPM stored mixed under the same condition, the setting time significantly increased with the period of storage, and the product contained dicalcium phosphate (CaHPO₄: DCP) as major phase, resulting in the loss of setting ability. The formation of DCP could be because of the weak driving force for setting, caused by a feeble supply of water from moisture. As the formation of DCPD requires stronger driving force to overcome the activation barrier, sufficient amount of water is essential. Humid environment during the storage decreased the driving force by the formation of DCP, and the driving force to produce DCPD was lost during the actual setting.

Abstract: In this research, the effect of stirring and aging time on the formation of β-tricalcium phosphate (β-TCP) powder was studied. β-TCP powder was synthesized using calcium nitrate tetrahydrate (Ca(NO₃)₂.4H₂O) (0.6M) and diammonium hydrogen phosphate (NH₄)₂HPO₄) (0.4M) via wet precipitation method. The mixture was stirred with different duration (1, 3, 5 and 7 hours) then centrifuged before washed with distilled water (twice) and ethanol followed by drying in oven (80°C, 24 hours). The cake was ground to form powder. The as prepared powder was analyzed using thermo-gravimetric (TGA) to determine the suitable calcinations temperature. TGA results show that the proper calcinations temperature was 800°C. The formation of β-TCP was characterized using X-ray Diffraction (XRD) analysis. Sample with optimum formation of β-TCP phase will choose for further study on the effect of aging time (0.5, 1, 20 and 24 hours). XRD analysis confirmed that sample stirred for 7 hours and aging for 24 hours produced β-TCP as major phase. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) proved that β-TCP powder form as agglomerated particles

Abstract: The present report aims to fabricate biphasic calcium phosphate (BCP) biocomposite in order to study the effects of sintering temperature on the sintered BCP biocomposite characteristics (phase’s formation, porosity and hardness properties). These effects were quantified using design of experiment (DOE) to develop mathematical models. BCP biocomposite pellets (60 wt% HA) were fabricated using mixing, pressing and sintered at two different temperatures (1100°C and 1250°C). The experiment was run by following the run order suggested by DOE software (Minitab 16) through randomization stage. Results show that sintering temperature will affect the formation of α-tricalcium phosphate (α-TCP) and the porosity of the samples. The formation of α-TCP phases will reduce the hardness value of BCP biocomposite.

Abstract: The influence of surface chemistry, roughness and hidrophilicity on the protein adhesion onto the biomaterial modulates the cell attachment, proliferation and differentiation. β-TCP is a synthetic bone substitute with bioactive, osteoconductive properties. Insulin is a polypeptide hormone that acts as a growth-stimulating factor for some cells types in culture. Few studies have been discussing this hormone role in bone remodeling and cells metabolism in vitro. The aim of this work was to evaluate the cell responses when insulin is adsorbed on β-TCP commercial discs surfaces. FTIR detected the characteristics bands of insulin adsorbed on sintered powder surface. The insulin adsorption on discs surface increase its wettability and favored growth and differentiation of the pre-osteoblastics cells. Although no addition of differentiation factors was present, it was observed deposits of extracellular matrix and collagen at 7 days in culture. The increase on affinity and cellular activity to the adsorbed insulin β-TCP substract was remarkable. It was quite clear that the insulin presents a role on activate and speed up the bone cells response while adhered to β-TCP substract. However, the insulin application on bone grafts for clinical purposes must be considered after detailed studies on animal models, which are required to fully evaluate the safe use of hormone containing grafts in clinical trials.