Applications of magnetic materials separation in biological nanomedicine

As a result of their advantages for superparamagnetic properties, good biocompatibility, and high binding capacity, functionalized magnetic materials became widely popular over the past couple of decades, being applied on large scale in various processes of sample preparation for biomedicine. In this work, we perform an in‐depth review on the current progress in the field of magnetic bead separation, discussing in detail the physical basis of this process, various synthesis methods and surface modification strategies. We place special focus of attention as well on the latest applications of magnetic polymer microspheres in cell separation, protein purification, immobilized enzyme, nucleic acid separation, and extraction of bioactive compounds with low molecular weight. Existing problems are highlighted and possible trends of magnetic separation techniques for biomedicine in the future are proposed.     

Effect of ring substitution on synthesis of benzimidazolium salts and their silver(I) complexes: characterization,electrochemical studies and evaluation of anticancer potential

Transition Metal Chemistry - A series of bidendate 5,6-dimethyl benzimidazolium-based N-heterocyclic carbene (NHC) proligands and their silver complexes were synthesized. The synthetic approaches...     

Unsymmetrically substituted benzimidazolium based Silver(I)-N-heterocyclic carbene complexes: Synthesis,characterization and in vitro anticancer study against human breast cancer and colon cancer

The promising biomedical applications of silver complexes stimulated the researchers to test these compounds against cancer. The present research work was designed to achieve this goal. In this work, a series of 5-methyl benzimidazole based N-Heterocyclic carbene ligands and respective silver(I) complexes were synthesized and tested on cancer cell lines to assess their anticancer activity. Unsymmetrically substituted benzimidazole was found unique in its reactivity and generation of a single product during NHC ligand formation was only possible after two successive alkylations with same alkyl halide. The corresponding Ag(I)-NHC adducts were obtained by in situ deprotonation of the NHC ligands. Synthesized compounds were characterized by various physcio-chemical and spectroscopic methods. Single crystal X-ray diffraction study of complex 7 revealed its mononuclear structure. Preliminary in vitro anticancer study of azolium salts and respective Ag(I)-NHC complexes against human breast cancer (MDA-MB-231), colon cancer (HCT-116) and normal endothelial cells (EA.hy926) cells revealed that all the compounds are more cytotoxic to cancer cells than normal cells and the complexes are relatively more potent compared to the corresponding NHC ligands. It was found that increased chain length and presence of methyl substituent on benzimidazole ring enhance the biopotency of Ag(I)-NHC complexes. The synthesized compounds were further studied for pro-apoptotic mechanism of action via Rhodamine 123 test. The tested compounds were found to induce apoptosis via extrinsic mitochondrial pathway.     

Synthesis and mechanical properties of Zr-based bulk amorphous alloys

Design and characterization of bulk amorphous alloys has been an active area of research due to their promising thermal and mechanical properties. An alloy composition Z₆₅Cu₁₇Ni₁₀Al₈ was designed and synthesized by Cu mold casting. In the base alloy 2 at.% Gd was added to study its effect on thermal and mechanical properties. Characterization of the alloys was done by techniques of X-ray diffraction (XRD), differential scanning calorimetry (DSC) and field emission scanning electron microscopy (FESEM). Many thermal parameters were evaluated to investigate the thermal stability and glass-forming ability of the alloys. In addition, the mechanical properties like nanohardness, elastic modulus and elastic recovery were measured. Thermal properties and activation energy reduced while mechanical properties like nanohardness, elastic modulus and percentage elastic recovery (% R) increased with Gd addition.     

Synthesis and characterization of a multicomponent Fe-based bulk amorphous alloy

A new bulk metallic glass (BMG) Fe₆₀B₁₅Zr₁₀Co₇Mo_5.5Y₂Si_0.5 was synthesized by Cu mold casting. The alloy was characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) techniques. The thermal stability and glass-forming ability (GFA) of the alloy have been discussed by evaluating a number of thermal parameters. The maximum values of the key thermal parameters like T_rg (T_g/T_m, T_g/T_l), γ, δ and β parameters were found to be ～(0.66, 0.64), 0.407, 1.84 and 3.83, respectively. The alloy showed double stage crystallization process. The activation energies for crystallization were found to be 606.6 and 623.1 kJ/mol by Kissinger and Ozawa equations, which indicate the high thermal stability. Crystallization behavior of the alloy was explored by XRD. Mechanical properties like Vicker’s hardness, nanohardness and elastic modulus are found to be very promising.     

Vibrational spectroscopy and DFT calculations of N,N′‐dicyclohexylcarbodiimide

Infrared (IR) and Raman spectra were obtained for N,N′‐dicyclohexylcarbodiimide (DCC) in the solid state and in CHCl₃ solution. Structures and vibrational spectra of isolated, gas‐phase DCC molecules with C₂ and C_i symmetries, computed at the B3‐LYP/cc‐pVTZ level, show that the IR and Raman spectra provide convincing evidence for a C₂ structure in both the solid state and in CHCl₃ solution. Using a scaled quantum‐chemical force field, these density functional theory calculations have provided detailed assignments of the observed IR and Raman bands in terms of potential energy distributions. Comparison of solid‐state and solution spectra, together with a Raman study of the melting behaviour of DCC, revealed that no solid‐state effects were evident in the spectra. Copyright © 2010 John Wiley & Sons, Ltd.     

Green Synthesis of CeO2 Nanoparticles from the Abelmoschus esculentus Extract: Evaluation of Antioxidant,Anticancer, Antibacterial,and Wound-Healing Activities

Metal oxide nanoparticles synthesized by the biological method represent the most recent research in nanotechnology. This study reports the rapid and ecofriendly approach for the synthesis of CeO₂ nanoparticles mediated using the Abelmoschus esculentus extract. The medicinal plant extract acts as both a reducing and stabilizing agent. The characterization of CeO₂ NPs was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), and Fourier transform infrared spectroscopy (FTIR). The in vitro cytotoxicity of green synthesized CeO₂ was assessed against cervical cancerous cells (HeLa). The exposure of CeO₂ to HeLa cells at 10–125 µg/mL caused a loss in cellular viability against cervical cancerous cells in a dose-dependent manner. The antibacterial activity of the CeO₂ was assessed against S. aureus and K. pneumonia. A significant improvement in wound-healing progression was observed when cerium oxide nanoparticles were incorporated into the chitosan hydrogel membrane as a wound dressing.     

Development and validation of UHPLC‐MS/MS assay for rapid determination of a carvone Schiff base of isoniazid (CSB‐INH) in rat plasma: application to pharmacokinetic study

In this study, a fast UHPLC‐MS/MS method was developed and validated for the determination of a novel potent carvone Schiff base of isoniazid (CSB‐INH) in rat plasma using carbamazepine as an internal standard (IS). After a single‐step protein precipitation by acetonitrile, CSB‐INH and IS were separated on an Acquity BEH^TM C₁₈ column (50 × 2.1 mm, 1.7 µm) under an isocratic mobile phase, consisting of acetonitrile: 10 mM ammonium acetate (95:5, v/v), at a flow rate of 0.3 mL/min. Quantification was performed on a triple quadrupole tandem mass spectrometer in multiple reactions monitoring mode by using positive electrospray ionization source. The precursor to product ion transitions were set at m/z 270.08 → 79.93 for CSB‐INH and m/z 237.00 → 178.97 for IS. The proposed method was validated in compliance with US Food and Drug Administration and European Medicines Agency guidelines for bioanalytical method validation. The method was found to be linear in the range of 0.35–2500 ng/mL (r² ≥ 0.997) with a lower limit of quantification of 0.35 ng/mL. The intra‐ and inter‐day precision values were ≤12.0% whereas accuracy values ranged from 92.3 to 108.7%. In addition, other validation results were within the acceptance criteria and the method was successfully applied in a pharmacokinetic study of CSB‐INH in rats. Copyright © 2014 John Wiley & Sons, Ltd.     

Ramsey theory for hypergroups

Semigroup Forum - In this paper, Ramsey theory for discrete hypergroups is introduced with emphasis on polynomial hypergroups, discrete orbit hypergroups and hypergroup deformations of semigroups....