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    Interaction of water-soluble amino acid Schiff base complexes with bovine serum albumin: Fluorescence and circular dichroism studies

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 71, Issue 4 , 2008 , Pages 1617-1622 ; 13861425 (ISSN) Gharagozlou, M ; Mohammadi Boghaei, D ; Sharif University of Technology
    Fluorescence spectroscopy in combination with circular dichroism (CD) spectroscopy were used to investigate the interaction of water-soluble amino acid Schiff base complexes, [Zn(L1,2)(phen)] where phen is 1,10-phenanthroline and H2L1,2 is amino acid Schiff base ligands, with bovine serum albumin (BSA) under the physiological conditions in phosphate buffer solution adjusted to pH 7.0. The quenching mechanism of fluorescence was suggested as static quenching according to the Stern-Volmer equation. Quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between amino acid Schiff base complexes and BSA. The thermodynamic parameters ΔG, ΔH... 

    Molecular interaction between three-dimensional graphene aerogel and enzyme solution: effect on enzyme structure and function

    , Article Journal of Molecular Liquids ; Volume 265 , 2018 , Pages 565-571 ; 01677322 (ISSN) Ehtesabi, H ; Bagheri, Z ; Eskandari, F ; Ahadian, M. M ; Sharif University of Technology
    New membrane materials and processes have been extensively developed due to urgent needs for much more economic separation processes. Recently, graphene has been confirmed to be an excellent separation membrane. As there is no support in the obtained three-dimensional (3D) architecture constructed from tubular graphene network, it is possible to take full advantage of the large surface of graphene. In this study 3D graphene aerogels were synthesized by a simple method and modified to adjust hydrophilicity of the samples to achieve high liquid volumetric rate. Modified samples were used for the filtration of the enzymes including amylase, cellulase, lipase and protease. Slightly differently... 

    Site-specific protein conjugation onto fluorescent single-walled carbon nanotubes

    , Article Chemistry of Materials ; Volume 32, Issue 20 , 2020 , Pages 8798-8807 Zubkovs, V ; Wu, S. J ; Rahnamaee, S. Y ; Schuergers, N ; Boghossian, A. A ; Sharif University of Technology
    American Chemical Society  2020
    Semiconducting single-walled carbon nanotubes (SWCNTs) are among the few photostable optical emitters that are ideal for sensing, imaging, drug delivery, and monitoring of protein activity. These applications often require strategies for immobilizing proteins onto the nanotube while preserving the optical properties of the SWCNTs. Site-specific and oriented immobilization strategies, in particular, offer advantages for improving sensor and optical signaling responses. In this study, we demonstrate site-specific protein immobilization of a model of enhanced yellow fluorescent protein with a single engineered cysteine residue, using either single-stranded DNA or a pyrene-containing linker to... 

    Tunable circular conversion dichroism and asymmetric transmission of terahertz graphene metasurface composed of split rings

    , Article Optics Communications ; Volume 456 , 2020 Asgari, S ; Rahmanzadeh, M ; Sharif University of Technology
    Elsevier B.V  2020
    The asymmetric transmission (AT) has attracted wide attention due to its novel applications. In this paper, we propose and investigate a tunable polarization-dependent intrinsically chiral graphene metasurface composed of split ring arrays in terahertz (THz) region. The resonance frequency of the structure is sensitive to the graphene chemical potential. Circular conversion dichroism (CCD) of the proposed structure is tunable and is reached to 0.36. Our work paths a new approach to propose some other compact and on-chip polarization-dependent structures in THz region. Furthermore, our proposed structure could be a useful segment in polarization-dependent systems. © 2019 Elsevier B.V  

    Nano reengineering of horseradish peroxidase with dendritic macromolecules for stability enhancement

    , Article Enzyme and Microbial Technology ; Volume 50, Issue 1 , 2012 , Pages 10-16 ; 01410229 (ISSN) Khosravi, A ; Vossoughi, M ; Shahrokhian, S ; Alemzadeh, I ; Sharif University of Technology
    A simple bio-conjugation procedure to surround a single horseradish peroxidase (HRP) enzyme molecule with dendritic polyester macromolecules (polyester-32-hydroxyl-1-carboxyl bis-MPA dendron, generation 5) was proposed. The characterization of resultant nanoparticles entitled HRP dendrozyme, was performed by transmission electron microscopy, dynamic light scattering, gel permeation chromatography and Fourier transform infrared spectroscopy. The results showed that HRP nanoparticles were spherical in shape and have an average size of 14 ± 2. nm in diameter. Furthermore, bio-conformational characterization of HRP dendrozyme was performed by means of circular dichroism and fluorescence... 

    The Study of Chemistry in Space and Its Realtionship with Origin of Life

    , M.Sc. Thesis Sharif University of Technology Izadi, Homa (Author) ; Shafiee, Afshin (Supervisor)
    In this study the concept of the origin of life, as an important question, is investigated and reviewed.Then the possibility of the beginning of life from an extraterrestrial origin is studied via spectroscopy methods to analyze the role of the cosmic waves.Moreover, by considering the similarity between the chirality of the essential amino acids and extraterrestrial amino acids, found in meteors the various methods for studying the structure of molecules, as well as the possibility of the transfer of the central elements of life from space to the earth are reviewed in details.Finally, we suggest how chirality might be emerged due to the interaction of the molecule with the environment,... 

    Interaction of copper(II) complex of compartmental Schiff base ligand N,N′-bis(3-hydroxysalicylidene)ethylenediamine with bovine serum albumin

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 66, Issue 3 , 2007 , Pages 650-655 ; 13861425 (ISSN) Boghaei, D. M ; Farvid, S. S ; Gharagozlou, M ; Sharif University of Technology
    Circular dichroism (CD) spectroscopy, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the interaction between copper(II) complex of compartmental Schiff base ligand (L), N,N′-bis(3-hydroxysalicylidene)ethylenediamine, and bovine serum albumin (BSA) in 0.1 mol dm-3 phosphate buffer solution adjusted to physiological pH 7.0 containing 20% (w/w) dimethylsulfoxide at room temperature. CD spectra show that the interaction of the copper(II) complex with BSA leads to changes in the α-helical content of BSA and therefore changes in secondary structure of the protein with the slight red shift (2 nm) in CD spectra. From the voltammetric data, i.e. changes in... 

    The effect of mesoporous silica nanoparticle surface chemistry and concentration on the α-synuclein fibrillation

    , Article RSC Advances ; Volume 5, Issue 75 , Jul , 2015 , Pages 60966-60974 ; 20462069 (ISSN) Taebnia, N ; Morshedi, D ; Doostkam, M ; Yaghmaei, S ; Aliakbari, F ; Singh, G ; Arpanaei, A ; Sharif University of Technology
    Royal Society of Chemistry  2015
    The aggregation of an amyloid protein, α-synuclein (α-Syn), has been suggested as a potential cause of Parkinson's and several other neurodegenerative diseases. To explore the possibility of using nanoparticle-based therapeutic agents for the treatment of such diseases, we investigated the influence of surface chemistry and concentration of mesoporous silica nanoparticles (MSNPs) on the fibrillation of recombinant human α-Syn protein in the present work. Bare MSNPs as well as MSNPs of different surface functionalities, including 3-(2-aminoethyl amino) propyltrimethoxysilane (AAS), succinic anhydride (carboxyl), and polyethyleneimine (PEI) were prepared and characterized by electron... 

    Protein-nanoparticle interactions: Opportunities and challenges

    , Article Chemical Reviews ; Volume 111, Issue 9 , June , 2011 , Pages 5610-5637 ; 00092665 (ISSN) Mahmoudi, M ; Lynch, I ; Ejtehadi, M. R ; Monopoli, M. P ; Bombelli, F. B ; Laurent, S ; Sharif University of Technology
    The significant role of protein nanoparticle interactions in nanomedicine and nanotoxicity is emerging recently through the identification of the nanoparticles (NP) protein (biomolecule) corona. The dynamic layer of proteins and/or other biomolecules adsorbed to the nanoparticle surface determines how a NP interacts with living systems and thereby modifies the cellular responses to the NP. Ehrenberg and co-workers used cultured endothelium cells as a model for vascular transport of polystyrene NP with various functional groups, which showed that the capacity of the various NP surfaces to adsorb proteins was indicative of their tendency to associate with cells. The quantification of the... 

    Study of molecular conformation and activity-related properties of lipase immobilized onto core-shell structured polyacrylic acid-coated magnetic silica nanocomposite particles

    , Article Langmuir ; Volume 32, Issue 13 , 2016 , Pages 3242-3252 ; 07437463 (ISSN) Esmaeilnejad Ahranjani, P ; Kazemeini, M ; Singh, G ; Arpanaei, A ; Sharif University of Technology
    American Chemical Society 
    A facile approach for the preparation of core-shell structured poly(acrylic acid) (PAA)-coated Fe3O4 cluster@SiO2 nanocomposite particles as the support materials for the lipase immobilization is reported. Low- or high-molecular-weight (1800 and 100 000, respectively) PAA molecules were covalently attached onto the surface of amine-functionalized magnetic silica nanoacomposite particles. The successful preparation of particles were verified by scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential measurement, and Fourier-transform infrared (FTIR) techniques. Once lipase is covalently... 

    Structural stability and sustained release of protein from a multilayer nanofiber/nanoparticle composite

    , Article International Journal of Biological Macromolecules ; Volume 75 , April , 2015 , Pages 248-257 ; 01418130 (ISSN) Vakilian, S ; Mashayekhan, S ; Shabani, I ; Khorashadizadeh, M ; Fallah, A ; Soleimani, M ; Sharif University of Technology
    Elsevier  2015
    The cellular microenvironment can be engineered through the utilization of various nano-patterns and matrix-loaded bioactive molecules. In this study, a multilayer system of electrospun scaffold containing chitosan nanoparticles was introduced to overcome the common problems of instability and burst release of proteins from nanofibrous scaffolds. Bovine serum albumin (BSA)-loaded chitosan nanoparticles was fabricated based on ionic gelation interaction between chitosan and sodium tripolyphosphate. Suspension electrospinning was employed to fabricate poly-e{open}-caprolacton (PCL) containing protein-loaded chitosan nanoparticles with a core-shell structure. To obtain the desired scaffold... 

    Development of a novel nano-sized anti-VEGFA nanobody with enhanced physicochemical and pharmacokinetic properties

    , Article Artificial Cells, Nanomedicine and Biotechnology ; Volume 46, Issue 7 , 2018 , Pages 1402-1414 ; 21691401 (ISSN) Khodabakhsh, F ; Norouzian, D ; Vaziri, B ; Ahangari Cohan, R ; Sardari, S ; Mahboudi, F ; Behdani, M ; Mansouri, K ; Mehdizadeh, A ; Sharif University of Technology
    Since physiological and pathological processes occur at nano-environments, nanotechnology has considered as an efficient tool for designing of next generation specific biomolecules with enhanced pharmacodynamic and pharmacodynamic properties. In the current investigation, by control of the size and hydrodynamic volume at the nanoscale, for the first time, physicochemical and pharmacokinetic properties of an anti-VEGFA nanobody was remarkably improved by attachment of a Proline-Alanine-Serine (PAS) rich sequence. The results elucidated unexpected impressive effects of PAS sequence on physicochemical properties especially on size, hydrodynamics radius, and even solubility of nanobody. CD...