جستجوی مقالات مرتبط با کلیدواژه "هیدروکسی آپاتیت" در نشریات گروه "شیمی"

The drug delivery approach in bone tissue engineering faces unique challenges due to the complex anatomy of bone and the limitations of drug delivery. In response, new pH-responsive nanocomposites, including magnetite nanoparticles (Fe3O4), Mobil Composition No. 41 (MCM-41), hydroxyapatite (HAP), 3-aminopropyltriethoxysilane (APTES), carboxymethyl cellulose (CMC), and montmorillonite (MMT) [(Fe3O4@MCM-41/HAP/APTES)] and hydrogel [(CMC/MMT/HAP)], have been developed for accurate delivery of teriparatide (PTH (1-34)) with the aim of increasing solubility, drug stability, and controlled release. These nanocomposites provide an efficient injectable dosing regimen that eliminates the side effects, safety concerns, and discomfort associated with repeated injections. Nanocomposites were characterized by various analytical techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), zeta potential analysis, dynamic light scattering (DLS), and field emission scanning electron microscopy (FE-SEM). The average crystal diameter of the nanocomposites was calculated as 27.6 ± 4 and 29.2 ± 1.4 nm, respectively, from Scherer's equation, and the drug-loaded nanocarriers had a hydrodynamic diameter of 417.023 ± 8.3 and 193.48 ± 3.8 nm, respectively, and a stable surface charge of -31 and -40 mV, respectively. In addition, the efficiency of loading and entrapment was determined to be 37% and 90% for the first nanocomposite and 38% and 82% for the second nanocomposite, respectively. Drug release experiments using the dialysis method combined with high-performance liquid chromatography (HPLC) analysis showed a sustained release pattern. As pH decreased from 7.4 to 5.6, there was a corresponding increase in drug release. The results of the study of drug release kinetics followed the Higuchi model, which fully corresponded to the characteristics of the release target of the nanocarriers and teriparatide drug, and confirmed the preservation of the integrity of the nanocarrier. The results of the cytotoxicity test within 24 hours on the NIH3T3 cell line not only showed no toxicity but also recorded the effect of cell proliferation and differentiation, which was controlled and limited in the case of the Saos-2 cell line. Based on these findings, nanocomposites designed and manufactured with the greatest impact of components in bone tissue regeneration, as a drug delivery system, provide a very efficient approach to increase therapeutic effectiveness and thus overcome the limitations associated with drug delivery.

Pure hydroxyapatite nanocomposites with different amount of magnesium additive were synthesized using a simple sol-gel method. For this purpose, the initial gel was obtained by the chemical reaction of calcium, magnesium, and phosphorus-related precursors, and after remaining for 48 h at room temperature, it was dried for 24 h at 120˚C in an electric furnace. Finally, to remove the organic materials and volatiles, this product was placed at 600˚C for 3 h. This way, six samples with molar percentages of 0, 2, 4, 6, 8, and 10 of magnesium were prepared. To investigate the effect of magnesium amount on the nanocomposite properties, X-ray diffraction pattern (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) images were used, and also, compressive strength testing was performed. The results confirmed the successful synthesis of hydroxyapatite nanocomposites and showed that with increasing magnesium content, the crystal size decreases. Moreover, pure hydroxyapatite has a needle-like and plate-like microstructure, while in hydroxyapatite substituted with 4% magnesium, only needle-like structure is observable. In addition, in hydroxyapatite substituted with 10% magnesium, only plate-like structure is visible. Finally, the sample substituted with 4% magnesium showed the highest compressive strength, and the sample substituted with 10% magnesium ranked as the second one.

Fabrication of scaffolds for bone tissue engineering applications often involves the use of two distinct classes of calcium-containing biomaterials, namely calcium phosphates and calcium silicates. The selection of these materials is based on their biocompatibility and bioactivity. Although these bioceramics are very similar to natural bone from the point of view of mineral compounds, unlike bone, they are brittle. The current research examines the use of hydroxyapatite and tricalcium silicate, which are the most common calcium phosphates and calcium silicates, in the field of bone scaffold applications, respectively. The present study shows the effect of different concentrations of ceramic nanoparticles when combined with sodium alginate hydrogel on the construction of bone scaffolds by molecular dynamics simulation. Stability and self-assembly have been evaluated through several parameters such as solvent-accessible-surface-area, radius of gyration, radial distribution function, root mean square deviations, hydrogen bonding, van der Waals energy, electrostatic energy, and total energy. The simulation results show that the addition of 10% by weight of hydroxyapatite and tricalcium silicate to the sodium alginate hydrogel matrix leads to the formation of a more compact, stable, and less hydrated structure and can potentially affect the mechanical properties of the scaffold and its interaction with Cells help. The findings of this research show that tricalcium silicate samples have superior properties for making scaffolds compared to hydroxyapatite samples, especially in terms of combination with sodium alginate hydrogel. However, it is necessary to conduct experimental tests to confirm the results of the simulations.

Today, nanotechnology has wide application potential in various fields. The use of nanomaterials and nanostructures has been expanded due to their small size, high surface area, distinct properties and unique advantages in orthopedics. Implantable nanoscale biomaterials as essential components of orthopedic surgery have led to the development of this field. Recent advances in this technology have become important in orthopedics with bone tissue engineering, implantable materials, diagnosis and treatment. The application of nanotechnology in orthopedic implants can be extremely useful in improving the treatment of many types of bone defects and orthopedic injuries. Application of biocompatible nanomaterials to implants with the ability to promote cell growth, tissue regeneration, mimic cellular environment, better extracellular adhesion, bone formation and better fusion is important given their potential need and efficacy. Hydroxyapatite is one of the most important minerals and bio-ceramics of bone in orthopedic surgery due to its unique properties in recent years. This article reviews the preparation, application and benefits of nanotechnology in orthopedic implants based on hydroxyapatite.

So far, various methods have been proposed for the synthesis of hydroxyapatite nanoparticles as the main ingredient in bone and enamel. In each of these methods, by varying initial conditions of synthesis, samples of size and shape, and the ratio of length to diameter can be achieved. In this study, pure hydroxypropyl nanoparticles were prepared using calcium nitrate precursors (Ca (NO3) 2-4H2O) and diammonium hydrogen phosphate ((NH4) 2HPO4) by hydrothermal method. The purpose of this study was to investigate the effects of changes in reaction conditions and the synthesis of this material on the size and shape of the particles. X-ray diffraction (XRD) and scanning electron microscopy (SEM) nanoparticles were investigated. The results of the experiment indicate that the concentration of the raw materials, the method and temperature of calcining, the speed of the addition of materials, the use or non-use of surfactants can have different effects on the size and shape of the hydroxyapatite particles.