Showing 9 results for Hydroxyapatite
Volume 2, Issue 4 (3-2019)
Abstract
In this study, phenolic compounds-coated ZnO@HAP nanocomposite (Ph.ZnO@HAP) was synthesized and used to improve the physical and chemical properties of chitosan hydrogel for biological application. At first, the phenolic compounds were extracted from walnut green hulls. The synthesis of Ph.ZnO@HAP nanocomposite was performed with the assistance of extracted phenols using a hydrothermal method. Chitosan hydrogel was also prepared using NaHCO3 at 37°C. Hybrid hydrogels based on chitosan and Ph.ZnO@HAP nanocomposite were prepared in a similar way and then characterized by fourier-transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The antioxidant property, cytotoxicity, and osteogenesis of hybrid hydrogels were measured using DPPH radical scavenging method, MTT, and alkaline phosphatase enzyme assay, respectively. The FTIR spectra, FESEM images, EDX spectrum, and Zeta potential data showed that Ph.ZnO@HAP nanocomposites synthesized successfully with rod-like morphology, phenolic compounds coated on the surface and a negative particle surface charge. The results of DPPH experiment showed that the antioxidant property of the nanocomposite material increased in a concentration-dependent manner. The FESEM images of chitosan hybrid hydrogels with different concentrations of embedded Ph.ZnO@HAP nanocomposite showed that hybrid hydrogels have a more uniform porous structure, compared to the chitosan hydrogel. Moreover, by an increase in the nanocomposite concentration in the structure of hybrid hydrogels, the antioxidant property augmented. The results of the biological studies showed that the cytotoxicity of hybrid hydrogels on osteoblast-like cells (Saos-2) is lower than that of chitosan hydrogel. Also, hybrid hydrogels showed the higher potential in induction of osteogenesis than chitosan hydrogels.
, , Shahab Faghihi,
Volume 4, Issue 1 (10-2013)
Abstract
The aim of this study is to investigate the relationship between the structure and function of an osteocalcin derived peptide on hydroxyapatite nanocrystal formation. For this purpose, , a natural motif sequence consisting of 13 amino acids present in the first helix of osteocalcin was selected based on its calcium binding ability and synthesized in both acidic and amidic forms using solid phase method. Circular dichroism (CD) and electron microscopy were performed to examine the structure and function of synthesized peptides. Moreover, the effect of these peptides on the viability of osteoblast cells was evaluated. Electron microscopy analysis showed the formation of plate-like HA nanocrystals in the presence of amidic peptide. In contrast, amorphous calcium phosphate was formed in the presence of acidic peptide. CD spectra analysis confirmed the random coil structure with lower molar elipticity for amidic peptide. In addition, the amidic peptide significantly increased the proliferation of osteoblast cells. It is concluded that increased bioactivity, which only occurred in amidic peptide is attributable to C-terminal amidation. It is also proposed that peptides with the ability to promote HA formation have the potential to be utilized in hard tissue regeneration high bioactivity and biocompatibility.
Volume 5, Issue 3 (12-2021)
Abstract
Research subject: The use of hydroxyapatite nanoparticles (HAp) in traditional polymers as reinforcing agent has been reported. While there are a limited number of reports regarding the effect of HAp morphology on the mechanical properties of the polymeric matrix, no research on this effect on supermolecular polymers has been reported so far. This study investigates the hypothesis that incorporation of unidirectionally grown HAp nanoparticles (rod-like nanoparticles, rHAp) into supramolecular polycaprolactone (SPCL) leads to the synthesis of a new bioactive construct.
Research approach: For this, rHAp nanoparticles were first synthesized by microemulsion method and then functionalized with 2-ureido-4[1H]-pyrimidinone (UPy) groups. Moreover, PCL was functionalized and converted to supramolecular structures by reacting the hydroxyl terminal groups with UPy groups. Finally, SPCL/rHAp nanocomposites were synthesized by solution casting method and their structure and properties were examined using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), universal testing machine and simulated body fluid (SBF).
Main results: According to the results, microemulsion is an efficient procedure for the synthesis of rod-like nanoparticles with high phase purity. On the other hand, based on the results, it is possible to functionalize these nanoparticles with UPy. Tensile test showed that by incorporation of these modified nanoparticles into SPCL, a significant increase in both elastic modulus and tensile strength can be observed. In fact, while the initial PCL was a waxy solid, modification with UPy and then incorporation of modified nanoparticles made it an elastic material. Finally, the obtained results indicated high bioactivity of supramolecular nanocomposites compared to the sample without filler. Therefore, supramolecular SPCL/rHAp nanocomposites with bioactive properties and dynamic character can be used as a suitable replacement for bone tissue defects.
M. Bahri , S. Hasannia, B. Dabirmanesh , H.h. Zadeh,
Volume 10, Issue 4 (12-2019)
Abstract
Introduction: Nowadays, bone tissue repair with increasing bone disorders and injuries have special importance. Bone tissue engineering provided specific solutions to these problems. The present study was conducted with the aim of purification of recombinant fusion peptide containing hydroxyapatite affinity tag using the ceramic chromatography column.
Material & methods: In this study, a fusion peptide was designed which at one side comprised the heparin-binding domain sequence, which can be attached to various types of growth factors involved in tissue repair and entrap these factors at the site of the lesion. On the other side, it contained a tag, which included a sequence derived from a laboratory study based on phage expression. The reason for keeping the sequence of this tag is to attach the peptide to the scaffold containing hydroxyapatite and purifying the recombinant peptide by the hydroxyapatite column. Therefore, the gene sequence was optimized and synthesized for expression in the prokaryotic host of E.coli strain BL21. Then the gene sequence was subcloned by double digestion with the SacI and BamHI enzymes into the expression vector of pET-21a(+). The expression of the recombinant peptide was investigated by SDS-PAGE and western blot. In order to optimize the purification conditions, two-step purification was carried out by applying fundamental changes in the main work method of the manufacturer company and was purified with acceptable purity. Finally, the existence of peptide assemblies was investigated by the SLD method.
Finding: The results of PCR cloning, enzymatic digestion using SacI and BamHI enzymes and sequencing indicated the accuracy of the cloning process. On the other hand, expression of the fusion peptide was confirmed by SDS-PAGE and Western blot techniques, and its migration onto the gel resulted in a band cleavage of about 12 kDa. Changes made to the manufacturer's workflow allowed the purification process to be optimized and the results of the DLS method showed the purity of the purified peptide.
Conclusion: The results indicate the desirable expression and remarkable purity of the fusion peptide designed in this study.
Shabnam Abedin Dargoush, Shiva Irani, Alirerza Naderi Sohi, Masoud Soleimani, Hana Hanaee-Ahvaz,
Volume 12, Issue 2 (1-2022)
Abstract
Graphene-based nanomaterials are being investigated for their biocompatibility and bioactivity, as well as their ability to improve osteogenic differentiation. In this research, the base material, reduced graphene oxide (rGO) sheets, were decorated with hydroxyapatite and strontium (rGO / HAp-Sr) to induce osteogenic differentiation in adipose-derived mesenchymal stem cells. Different techniques were used to determine the properties of the nanocomposite such as diffraction analysis techniques (XRD) and transmission electron microscopy (to evaluate the size and morphology of HAp-Sr on rGO plates), FT-IR (to analyze the nanocomposite functional group), Raman spectroscopy (to investigate possible disorders in nanocomposite structure and number of layers), induced dual plasma emission spectroscopy (to assess atomic concentration of Ca and Sr), zeta potential(electrical potential of the nanocomposite) and MTT (nanocomposite cytotoxicity assessment) were used. The ossification potential of the synthesized nanocomposite was investigated and confirmed using the calcium deposition test in dipose-derived mesenchymal stem cells. According to the obtained results, osteogenic differentiation induction is possible using synthesized nanocomposites without the need for chemical inducers.
Volume 13, Issue 3 (8-2010)
Abstract
Objective: Silicon is an effective element in bone biomineralization; hence Si-substituted hydroxyapatite can be a relevant bioceramic as bone materials substitution.
Materials and Methods: Stoichiometric hydroxyapatite (HA) and Si-substituted hydroxyapatite (Si-HA) with different contents of Si substitution were synthesized successfully by a hydrothermal method using Ca(NO3)2, (NH4)3PO4 or (NH4)2HPO4 and Si(OCH2CH3)4 (TEOS) as starting materials.
Results: Crystalline Phases, chemical composition, microstructure and morphology of synthesized powders were investigated using X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), inductively coupled plasma AES (ICP-AES) and scanning electron microscopy (SEM) techniques. The results proved silicon substitution in hydroxyapatite structure and revealed that the substitution of phosphate groups by silicate groups caused some OH- loss to maintain charge balance and the lattice parameters slightly changed with respect to stoichiometric HA.
Conclusion: Si-incorporation reduces the crystallites size of Si-HA and crystallinity, thus the solubility of Si-HA powders increases, and as a result Si- substitution has improved bioactivity behavior of HA. Based on in-vitro tests; soaking and incubating the specimens in simulated body fluid (SBF) and MTT assays (Dimethylthiazol assay), Si-substituted hydroxyapatite is more bioactive than pure hydroxyapatite.
Fatemeh Afraei, Sara Daneshjou, Bahareh Dabirmanesh,
Volume 14, Issue 2 (5-2023)
Abstract
Chondroitinase ABCI is a bacterial lyase that degrades glycosaminoglycans and promotes axonal growth and functional improvement. However the stability and maintenance of this enzyme is very limited. One of the strategies to overcome this limitation is to immobilize the enzyme. In this research, chondroitinase ABCI (cABCI) from Proteus Vulgaris was immobilized on hydroxyapatite nanoparticles. Hydroxyapatite is a non-toxic ceramic biomaterial that has a high surface area, which is beneficial for loading a large amount of enzyme. Therefore, to increase the stability of chondroitinase ABCI, immobilization on hydroxyapatite nanoparticles for 4 hours through physical adsorption in phosphate buffer pH 5, 6.8, and 8 at 4◦C was carried out. Enzyme immobilization on hydroxyapatite nanoparticles was then confirmed by field emission gun-scanning electron microscopy and UV-spectroscopy, before and after immobilization. Then, in order to obtain the optimal pH and temperature, the activity of the nanosystem was investigated at three pH and temperatures (4°C, 25°C, and 37°C). Results revealed higher activity at pH 5 and temperature 4 ◦C than the other pH and temperatures for the nanosystem. Based on the obtained results, which show the stability of the nanosystem at all three temperatures compared to the free enzyme, this nanosystem could be a potential candidate for clinical applications in future.
Volume 17, Issue 4 (1-2015)
Abstract
Objective:More similarity to in vivo medium may help to increase the proliferation and differentiation of cells at in vitro condition. The present study has investigated the effect of a dynamic mediumand nano hydroxyapatite (nHA) presence on proliferation and differentiation of mesenchymal stem cells (MSCs) to bone cells using electrospun polycaprolactone (PCL) scaffolds. Methods: We prepared PCL and PCL-nHA scaffolds by electrospinning. After static culturing of the scaffolds with MSCs, the scaffolds in a 14-day period, they were divided into two groups of static and dynamic cultures. The dynamic culture scaffolds were placed on a shaker. Cell proliferation and differentiation at days 3, 7 and 14 were investigated by MTT, and the calcium and alkaline phosphatase assays. Results: The obtained results from the MTT assay on day 14 showed an increase of 1.1 times in cell proliferation in the dynamic culture compared to the static culture. During this period, the calcium content produced by cells in the dynamic culture at day 14 were 1.23 times higher for the PCL scaffold and 1.46 times higher for the PCL-nHA scaffold compared to the static culture. Alkaline phosphatase levels for the dynamic state PCL scaffold were 1.24 times more and for the PCL-nHA scaffold they were 1.28 times more compared to the static culture at day 14. Conclusion: The obtained results from dynamic culture, showed higher proliferation and differentiation of stem cells to bone for both PCL and PCL-nHA scaffolds compared to the static culture. The amount of cell proliferation and differentiation in the scaffolds that contained nHA was more than scaffolds that did not have nHA.
Volume 17, Issue 12 (2-2018)
Abstract
The main purpose of using scaffolds replacement tissues of the body. The most important part is to choose the type and steel scaffolding so that eventually will replace the damaged tissue. One of the mechanisms proposed to reshape the bone is based on its piezoelectric properties. It seems that the use of piezoelectric materials is an option for use in the body, is a unique privilege. Therefore, the ceramic barium titanate (BaTiO3) having good piezoelectric properties, Curie temperature of about 125˚C and laboratory observations that non-toxic in the body, as a candidate to replace and simulate the performance of bone tissue, has been proposed. In this study, the design and produce of barium titanate piezoelectric ceramic as a bone scaffold with foam casting method and become coated with gelatinous and nanostructured HA composite for bone tissue engineering. Then test its properties by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and mechanical properties were studied. In the end, it was concluded that the barium titanate scaffold produse with foam casting method coated with gelatin nano hydroxyapatite composite structure suitable for use in bone tissue engineering.
