Biomedical and Biotechnology,
Y. Beygi-Khosrowshahi; S. Zakhireh
Abstract
Bone tissue engineering requires approaches to provide a suppression/promotion environment for the bone growth. Scaffold biomaterials have profound regulatory effects on the functionality of mesenchymal stem cells (MSCs). In the present study, the three-component bioceramic of selenium/reduced graphene ...
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Bone tissue engineering requires approaches to provide a suppression/promotion environment for the bone growth. Scaffold biomaterials have profound regulatory effects on the functionality of mesenchymal stem cells (MSCs). In the present study, the three-component bioceramic of selenium/reduced graphene oxide/hydroxyapatite (Se/RGO/HA) was developed and its performance to repair bone defects was compared to that of HA. The Se/RGO/HA nanocomposite scaffold was synthesized using the chemical bath technique, characterized by the X-ray diffraction spectra, field emission scanning electron microscopy, energy dispersion X-ray spectrometery, and Fourier transform infrared spectroscopy analyses. Human adipose-derived MSCs (hAD-MSCs) were used to investigate the in-vitro osteogenic properties of the Se/RGO/HA scaffold. The effect of the combined scaffold on the cell proliferation was analyzed by the MTT assay. Cell adhesion behaviors were evaluated using the optical microscopy and SEM. The osteogenic properties of the Se/RGO/HA scaffold were examined by the measurement of the alkaline phosphatase (ALP) activity and western blotting technique. The hAD-MSCs proliferation for HA and the Se/RGO/HA nanocomposite were 2 ± 0.1 and 1.1 ± 0.05 respectively. The Se/RGO/HA nanocomposite had cytotoxic effects on the KHOS-240S cancer cells. Additionally, good cell attachment and osteoblast-like morphology were characterized on the designed scaffold. The ALP activity and mineralization potential of cells seeded on Se/RGO/HA were higher than those seeded on HA. The Osteocalsin protein for Se/RGO/HA and HA were 64 ± 1 and 12 ± 0.1 respectively. Furthermore, the expression of Osteocalcin, a bone-specific protein, was synergistically increased by the incorporation of Se and RGO into HA. In conclusion, the presence of RGO inside Se could significantly increase the positive effects of HA on the osteogenic potential of hAD-MSCs.
Separation Technology,
N. Mostafazadeh; A.A. Ghoreyshi; K. Pirzadeh
Volume 15, Issue 4 , November 2018, , Pages 27-47
Abstract
In this study, ZIF-67 was synthesized through solvothermal method to remove Cr(VI) ions from aqueous solution. To improve the structural properties of ZIF-67 and its adsorption capacity, optimization of the synthesis conditions was carried out based on maximum Cr(VI) uptake. From experiments, the optimum ...
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In this study, ZIF-67 was synthesized through solvothermal method to remove Cr(VI) ions from aqueous solution. To improve the structural properties of ZIF-67 and its adsorption capacity, optimization of the synthesis conditions was carried out based on maximum Cr(VI) uptake. From experiments, the optimum condition was revealed as solvent: metal ion molar ratio of 4.6:1, ligand: metal ion molar ratio of 318:1 and temperature of 23℃. The physio-chemical properties of as-synthesized ZIF-67 were investigated by BET, XRD, FTIR and FESEM analyses. Effect of adsorption pH, adsorbent dosage, initial concentration and contact time on adsorption process was investigated. Based on the results, the maximum adsorption capacity of Cr(VI) was 26.27 mg/g which was obtained at 35℃, pH= 5, adsorbent dosage of 3 g/l and initial concentration of 107.82 mg/l. The equilibrium time for Cr(VI) adsorption varied from 180 min for low initial concentration of 9 mg/L to 240 min for a high initial concentration of 90 mg/L. For the synthesized ZIF-67, maximum uptake capacity was reported 26.27 mg/g at initial concentration of 107.82 mg/l. The equilibrium data were described better by Langmuir-Freundlich isotherm model than the other models at three different temperatures. Pseudo-second-order model fitted the experimental data better than pseudo-first-order one. Adsorption thermodynamics indicated that the adsorption process was endothermic and spontaneous in nature. The regenerability of ZIF-67 was also studied in three sequential cycles and the Cr(VI) adsorption was almost retained after two cycles.