Sharif Digital Repository

In this work, the synthesized graphene oxide/TiO2/doxorubicin (GO/TiO2/DOX) composites were loaded into the chitosan/poly(lactic acid) (PLA) solutions to fabricate the electrospun chitosan/PLA/GO/TiO2/DOX nanofibrous scaffolds via electrospinning process. The synthesized composites and nanofibers were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Three-factor three-level central composite design was used to determine the influence of PLA to chitosan ratio, TiO2/DOX content and GO/TiO2/DOX content on the release of DOX from nanofibrous scaffolds. Drug loading efficiency and drug release behavior from... 

In this study, lyophilized advanced platelet rich fibrin (A-PRF) was used in combination with collagen-chitosan membrane for the first time to combine advantages of both collagen and A-PRF membranes. Response surface methodology (RSM) was used to design the experimental condition and to correlate the effects of parameters, including chitosan/collagen (chit/col) weight ratio and A-PRF concentration on Young's modulus, mesenchymal stem cell (MSCs) viability and degradation rate of the membranes. Results showed that Young's modulus of the membranes was intensified by increasing chit/col weight ratio and decreasing A-PRF concentration from 3 to 8 MPa. Cell viability of MSCs was improved by both... 

In order to evaluate the long-term viability, the iron content stability, and the labeling efficiency of mammalian cells using magnetic cell labeling; dextran-coated ultrasmall superparamagnetic iron oxide (USPIOs) nanoparticles with plain surfaces having a hydrodynamic size of 25 nm were used for this study. Tests were carried out in four groups each containing 5 flasks of 5.5 × 10 6 AD-293 embryonic kidney cells. The cell lines were incubated for 24 h using four different iron concentrations with and without protamine sulfate (Pro), washed with phosphate-buffered saline (PBS) and centrifuged three times to remove the unbounded USPIOs. Cell viability was also verified using USPIOs. There... 

In this paper, a bottom-up hydrothermal route is reported for the synthesis of oxygen and nitrogen co-decorated carbon quantum dots (CQDs) using ammonium hydrogen citrate (AHC) as a single precursor. DLS data approved the formation of 4.0 nm (average size) CQDs. XRD pattern shows the interlayer spacing (002) of 3.5 Å for CQDs, which is exactly the same as that of crystalline graphite. XPS and FTIR spectra verified the formation of oxygen and nitrogen functional groups on the CQDs surface. Co-decorated carboxyl, hydroxyl and amine groups on the CQDs surfaces make them as promising polyelectrolyte for gene delivery. Toxicity assay showed a survival rate of 70% under different incubation times... 

Adaptation of Penicillium simplicissimum with different heavy metals present in a spent hydrocracking catalyst, as well as one-step, two-step, and spent medium bioleaching of the spent catalyst by the adapted fungus, was examined in batch cultures. Adaptation experiments with the single metal ions Ni, Mo, Fe, and W showed that the fungus could tolerate up to 1500. mg/L Ni, 8000. mg/L Mo, 3000. mg/L Fe, and 8000. mg/L W. In the presence of multi-metals, the fungus was able to tolerate up to 300. mg/L Ni, 200. mg/L Mo, 150. mg/L Fe and 2500. mg/L W. A total of 3% (w/v) spent catalyst generally gave the maximum extraction yields in the two-step bioleaching process (100% of W, 100% of Fe, 92.7%...