The sol-gel process is a technique used to synthesize materials from colloidal suspensions and, therefore, is suitable for preparing materials in the nanoscale. In this work hydroxyapatite was used due to its known properties in tissue engineering. Hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 is a bioactive ceramic which is found in the mineral phase of bone tissue and is known for its great potential in tissue engineering applications. For this reason, this material can be applied as particle aggregates on ceramic slurry, coating or film on materials with a poorer biological response than hydroxyapatite. In this work, hydroxyapatite gel was obtained by the sol-gel process and applied as nanoparticle aggregation in the mixture of hydroxyapatite and tricalcium phosphate to form a ceramic slurry. This process is the polymer foam replication technique used to produce scaffolds, which are used in tissue engineering. For HA gel characterization it was used enviromental scanning electron microscopy (ESEM), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF). The crystallite size was calculated from XRD data using the Scherrer equation. The nanoparticles size before firing was approximately 5nm. The crystallite size calculated after calcination was approximately 63 nm. The EELS results showed that calcium phosphate was obtained before firing. After HA gel calcination at 500 °C the XRD results showed hydroxyapatite with a small content of beta-TCP. The scaffolds obtained by polymer foam replication technique showed a morphology with adequate porosity for tissue engineering.
Particle size is one of the most important factors to the successful application of calcium phosphate bioceramics as it may have an important role on its final properties such as mechanical resistance and reactivity. Thus, a process which results on very small and homogeneous particles is required, since it avoids further contamination derived from long milling times. On this context, a process such as sol-gel synthesis may be feasible, due to its simplicity on handling and its well known characteristic of producing homogeneous nanoparticles. Moreover, precipitated HA also may lead to satisfactory results regarding particle size and phase purity. The aim of this article was to demonstrate a preliminary characterization study of powders obtained by both methods and to compare them to a commercial sample available in Brazil. Characterization was made by XRD, Scherrer’s equation, XRF, SEM-LV, SEM-FEG and SEM-EDS. It has been found out that all samples consist of pure nanostructured hydroxyapatite with crystallite size between 37nm and 62nm.
Scaffolds produced with ceramics are commonly used as bone substitute. In this work calcium phosphate materials were used to produce the scaffolds, because HA and TCP have many similarities with bone tissue. For crystalline phase analysis the scaffolds were calcined at 750 °C and sintered at 1330 °C. Electron microscopy images showed HA and TCP nanoparticles and the compounds were identified by Fourier transform infrared spectrometer. X-ray diffraction showed this material to be mostly crystalline. X-ray fluorescence identified chemical contaminants. X-ray micro computerized tomography produces tomographic images of the objects in 360°. In vitro testing was used to study cells behavior in contact with this material in a controlled environment.
Tissue engineering is an important emerging area for creating biological alternatives for harvested tissues, implants, and prostheses. Biocompatible and biodegradable polymeric materials are considered an important class of materials that can be used as scaffolds in tissue engineering applications. In this work, the system studied was nanocomposites of hydroxyapatite (HA) dispersed in a matrix of PLLA. Scaffolds have to present similar structure and also function as an artificial extracellular matrix for cell attachment and growth. Hydroxyapatite is a bioactive ceramic and has been used in applications of repairing bone tissue due to its biocompatibility and osteoconductivity. Poly(L- lactic acid) is a biodegradable and biocompatible polymer and has been used in different applications in the biomedical field. In this work, polymer solutions were prepared with different percentages of hydroxyapatite and porous membranes consisting of non-woven nanostructured fibers were obtained by electrospinning. The process parameters were: voltage of 13kV, flow rate of 0.5 ml/h and distance from the tip of the needle to the collector of 12 cm. By using these process parameter, fibrous membranes were obtained with different concentrations of HA (1.96, 4.76, 9 [wt %]). The morphology of the samples was observed by SEM and the characteristic physic-chemical were analyzed by XRF, XRD, DSC and FTIR.
Purpose Tissue engineering performs the culture of cells on scaffolds, aiming at the restoration of damaged tissue. For the cell culture into the scaffold, it is necessary to establish certain conditions, such as the type of supplementation of the culture medium. Therefore, the aim of this research was to evaluate the platelet-rich plasma (PRP) as a supplement and scaffold for Vero cell culture, in a one case report study. Methods Calcium chloride was added to the PRP, obtained by apheresis. After PRP retraction, serum from PRP (SPRP) and the clot from PRP (CPRP) were obtained. SPRP was used as a supplement to the culture medium, and CPRP was utilized as a scaffold. Results The evaluation of SPRP as a supplement showed that there was no statistical difference in cell viability compared to cultures supplemented in the standard way, with fetal bovine serum (FBS), after 24 h of culture. The morphological analysis, carried out on the third and fifth days, did not verify changes in the typical morphology of Vero cells cultured with SPRP. For the use of CPRP, its structure was observed. The CPRP was formed by an irregular network of fibers with different diameters, having a mean value of 0.210 ± 0.097 μ. In the analysis of CPRP as a scaffold, it was verified that the cells adhered and spread over the biomaterial. Conclusion Therefore, in Vero cell cultures, the results suggest that SPRP and CPRP can be used as a supplement and scaffold, respectively.
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