توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Preparation, Characterization and Application of Fe3O4 [email protected]@mSiO2 Nanocomposite Particles for Lipase Immobilization
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۸
Multifunctional Fe3O4 clusters\nonporous SiO2\mesoporous SiO2 (core\shell\shell) nanocomposite particles were prepared in order to develop a lipase–based recyclable nanobiocatalyst used in the biofuel production. Magnetite nanoparticles were synthesized by coprecipitation method and their clusters were coated by a silica thin shell using the modified Stöber method. Through a template removing approach, a mesoporous silica shell was formed on the nonporous silica. Calcination method in the presence of complex salts was used to expand the pore size of nanoparticles. The obtained nanoparticles possess superparamagnetism, high magnetization, high mean pore diameter (28.5 nm), high surface area (26 m2\g), and large pore volume (0.187 cm3\g). Once nanocomposite particles were prepared, lipase molecules were covalently immobilized onto nanocomposite particles by using glutaraldehyde as an activating agent. Finally, the loading and activity of the immobilized lipase were measured.<\div>

۲Reinforcing alginate beads by incorporating amine–functionalized silica nanoparticles for 3D cell culture applications
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۷
Novel alginate–silica nanocomposite beads were prepared wih an improved mechanical stability for the mammalian cell culture purposes, without any decrease in the cell viability compared to bare alginate beads . Three types of monodispersed spherical silica nanoparticles with sizes of 165±7, 450±10 and 660±25 nm were synthesized using the template–removing method and then were amine–functionalized with N–(2–aminoethyl)–3–aminopropyl trimethoxy–silane (EDS). Modification of nanoparticles with EDS provided a positive charge on the surface of nanoparticles, and consequently enhanced the bead integrity and the attachement of mammalian cells. Prepared nanoparticles were used as the filler in the alginate polymer matrix. In comparison with the conventional alginate beads, the synthesized nanocomposites presented an enhanced mechanical stability and long–term durability. The cell cultivation tests revealed that incorporating amine–functionalized silica nanoparticles into alginate beads has no negetive effect on the CHO cell density and viability<\div>

۳Optimizing Primary Recovery and Refolding of Human Interferon–b from Escherichia coli Inclusion Bodies
اطلاعات انتشار: Iranian Journal of Biotechnology، دوازدهم،شماره۴(پياپي ۴۸)، ۲۰۱۴، سال
تعداد صفحات: ۹
Background: The refolding of proteins from inclusion bodies is affected by several factors, including solubilization of inclusion bodies by denaturants, removal of the denaturant, and assistance of refolding by small molecule additives.Objectives: The purpose of this study was optimization of recombinant human interferon β purification in order to achieve higher efficiency, yield, and a product with a better and more suitable biological activity.Materials and Methods: Triton X–100 and sodium deoxycholate were used to wash the recombinant human interferon–β inclusion bodies prior to solubilization. The inclusion bodies solubilization process was performed by denaturants and reducing agents; guanidine–hydrochloride, urea, β–mercaptoethanol and dithiothritol.Results: The best recovery was obtained in the presence of 0.5% TritonX–100 (v\v). Low concentrations of urea only gave a marginal improvement on the refolding of recombinant human interferon–β. Successful refolding was achieved by gradient elution (decreasing the guanidine–hydrochloride concentration) in the presence of L arginine. Partial purification was also achieved continuously, and recombinant human interferon–β was recovered with 93.5% purity. The interferon prepared in this project was biologically active and inhibited the replication of vesicular stomatitis virus in Hela cells, when compared to the standard interferon. Conclusions: In this research, the best recovery of inclusion bodies was found at a concentration 0.5 M of Triton X–100, the maximum efficiency of solubility was found in pH 10.5 and the maximum efficiency of refolding was achieved by final buffer containing 2M urea and 0.6 M L–Arg.

۴Preparation and Characterization of Double Shell Fe3O4 [email protected] [email protected] SiO2 Nanocomposite Spheres and Investigation of their In Vitro Biocompatibility
اطلاعات انتشار: Iranian Journal of Biotechnology، سيزدهم،شماره۱(پياپي ۴۹)، ۲۰۱۵، سال
تعداد صفحات: ۱۰
Background: Multifunctional core–shell magnetic nanocomposite particles with tunable characteristics have been paid much attention for biomedical applications in recent years. A rational design and suitable preparation method must be employed to be able to exploit attractive properties of magnetic nanocomposite particles.Objectives: Herein, we report on a simple approach for the synthesis of magnetic mesoporous silica nanocomposite particles (MMSPs), consisted of a Fe3O4 cluster core, a nonporous silica shell and a second shell of the mesoporous silica of suitable sizes for biomedical applications and evaluate their cytotoxicity effects on human cancer prostate cell lines.Materials and Methods: Clusters of magnetite (Fe3O4) nanoparticles were coated by a layer of nonporous silica using Stöber method. The coating step was completed by an outer layer of mesoporous silica via template–removing method. Structural properties of MMSPs were investigated by FTIR, HR–S(T)EM, BET, XRD techniques and magnetic properties of MMSPs by VSM instrument. MTT and LDH assays were employed to study the cytotoxicity of MMSPs.Results: Obtained results revealed that decreasing the precursor concentration and the reaction time at the nonporous silica shell formation step decreases the thickness of the nonporous silica shell and consequently leads to the formation of smaller MMSPs. The as–prepared MMSPs have a desirable average size of 180±10 nm, an average pore size of 3.01 nm, a high surface area of 390.4 m2.g–1 and a large pore volume of 0.294 cm3.g–1. In addition, the MMSPs exhibited a superparamagnetic behavior and a high magnetization saturation value of 21±0.5 emu\g. Furthermore, the viability tests of DU–145 cell lines exposed to various concentrations of these particles demonstrated negligible cytotoxicity effects of the as–prepared particles. Conclusions: These results demonstrate interesting properties of MMSPs prepared in this study for biomedical applications.

۵The Effects of Organic Solvents on the Physicochemical Properties of Human Serum Albumin Nanoparticles
اطلاعات انتشار: Iranian Journal of Biotechnology، چهاردهم،شماره۱(پياپي ۵۳)، ۲۰۱۶، سال
تعداد صفحات: ۶
Background: Recently, applications of albumin nanoparticles as drug delivery carriers have increased. Most toxicology studies have shown that surface chemistry and size of nanoparticles play an important role in biocompatibility and toxicity. Objective: The effect of desolvating agents with different chemical properties on the size of synthesized HSA NPs was investigated. Materials and Methods: Acetone, ethanol, methanol, and acetonitrile were used to synthesize HSA NPs with controllable size by desolvation method. Scanning electron microscopy (SEM), dynamic light scattering (DLS), and circular dichroism (CD) were employed to characterize produced particles. Finally, the toxicity of HSA NPs synthesized under different conditions was evaluated on PC–12 cells. Results: The sizes of synthesized particles differed according to the different solvents used. The sizes were 275.3 nm, 155.3 nm, 100.11 nm, and 66.2 nm for acetonitrile, ethanol, acetone, and methanol, respectively. CD showed that larger NPs had more changes in the secondary structures. Finally, the toxicity monitored on the cultured PC–12 cells showed no significant toxic effect through treating with these NPs at different concentrations (0–500 mg.mL–1). Conclusions: The size of HSA NPs has a strong dependency on the desolvating agent. The mechanism in which the desolvating agent affects the size of HSA NPs is complex. Various factors such as dielectric constant, polarity, functional groups, and hydrogen bonding of the solvents have the potential to affect the size and structure of HSA NPs. CD analysis suggested that the solvent denaturing capability had a critical effect on the HSA particle size. The stronger denaturing capability of the solvent resulted in the larger HSA particle size.
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