Search for: dendrimers
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    On omega and related polynomials of dendrimers

    , Article Studia Universitatis Babes-Bolyai Chemia ; Issue 1 , 2013 , Pages 63-70 ; 12247154 (ISSN) Ghorbani, M ; Hosseinzadeh, M. A ; Sharif University of Technology
    Omega polynomial was introduced by Diudea. Following Omega polynomial, the Sadhana polynomial was defined by Ashrafi et al. In this paper we compute Omega and Sadhana polynomials of three classes of dendrimers  

    Computing ABC4 index of nanostar dendrimers

    , Article Optoelectronics and Advanced Materials, Rapid Communications ; Volume 4, Issue 9 , 2010 , Pages 1419-1422 ; 18426573 (ISSN) Ghorbani, M ; Hosseinzadeh, M. A ; Sharif University of Technology
    The ABC index is a topological index was defined as where dG(u) denotes degree of vertex u. Now we define a new version of ABC index as where The goal of this paper is further the study of the ABC4 index  

    A note of Zagreb indices of nanostar dendrimers

    , Article Optoelectronics and Advanced Materials, Rapid Communications ; Volume 4, Issue 11 , April , 2010 , Pages 1877-1880 ; 18426573 (ISSN) Ghorbani, M ; Hosseinzadeh, M. A ; Sharif University of Technology
    The Zagreb indices have been introduced more than thirty years ago by Gutman and Trinajstić. In this paper we introduce a new version of Zagreb indices and then we compute them for an infinite family of nanostar dendrimers  

    Dendrimer-like supramolecular nanovalves based on polypseudorotaxane and mesoporous silica-coated magnetic graphene oxide: a potential pH-sensitive anticancer drug carrier

    , Article Supramolecular Chemistry ; Volume 28, Issue 7-8 , 2016 , Pages 624-633 ; 10610278 (ISSN) Pourjavadi, A ; Mazaheri Tehrani, Z ; Shakerpoor, A ; Sharif University of Technology
    Taylor and Francis Ltd 
    In the present research, two types of drug carriers based on mesoporous silica-coated magnetic graphene oxide, Fe3O4@GO@mSiO2, were synthesised and the pH-responsive behaviour for doxorubicin release was investigated. One type of the carrier was dendrimer-like multi ethylene amine grafted on Fe3O4@GO@mSiO2 and the other was dendrimer-like supramolecular polypseudorotaxane. Herein, α-cyclodextrin was used in the structure of supramolecular nanoparticles as a gatekeeper to inhibit the drug from escaping at neutral pH (the pH of healthy tissue). The drug release profile showed that the supramolecular nanocarrier was more sensitive to the pH changes. The content of drug release was about 100% at... 

    Magnetic nanoparticles coated by acidic functionalized poly(amidoamine) dendrimer: Effective acidic organocatalyst

    , Article Catalysis Communications ; Volume 28 , 2012 , Pages 86-89 ; 15667367 (ISSN) Pourjavadi, A ; Hosseini, S. H ; Hosseini, S. T ; Aghayeemeibody, S. A ; Sharif University of Technology
    A novel magnetic Br∅nsted acid catalyst was synthesized based on growing poly(amidoamine) dendrimers on the surface of magnetic nanoparticles. After the dendronizing process, the MNP coated PAMAM was functionalized by chlorosulfuric acid to form an acid catalyst. Because of dendrimer coating of MNPs, catalyst shows good loading level of acidic groups on the surface. Also zwitterion nature of catalyst surface improves the catalytic activity. This new catalyst is proven to be highly effective in the synthesis of α-aminophosphonate compounds in a green way  

    Carbosilane dendrimers: Drug and gene delivery applications

    , Article Journal of Drug Delivery Science and Technology ; Volume 59 , 2020 Rabiee, N ; Ahmadvand, S ; Ahmadi, S ; Fatahi, Y ; Dinarvand, R ; Bagherzadeh, M ; Rabiee, M ; Tahriri, M ; Tayebi, L ; Hamblin, M. R ; Sharif University of Technology
    Editions de Sante  2020
    Carbosilane dendrimers are a particular type of dendrimer structure that has been used as delivery vehicles for drugs and nucleic acids. They have a defined structure according to their generation number, and their terminal groups can be rendered cationic or anionic. The cationic charges can address the limitation of electrostatic repulsion between the negatively charged phosphate groups of nucleic acids and negatively charged cell membranes. Specific drugs can be loaded into the central part of the dendrimer or attached at the exterior, and the overall positive charge may improve the efficacy of anti-inflammatory drugs. One promising feature of dendrimers is their non-toxicity both in vitro... 

    Dendrimers and Other Nanostructures by the Approach of Graph Theory

    , M.Sc. Thesis Sharif University of Technology Mohammad Hasani, Behtash (Author) ; Mahmoodian, Ebadollah (Supervisor)
    In this thesis, we study the application of graph theory in chemistry. Such as, molecular graphs, modeling, algorithms, topologicalindicesandsoon. Themaingoalinthisresearchis collecting problems in chemistry which have mathematical models, specially in graph theory. Also we study the methods applied to them by considering the problems in chemistry with mathematical approach. In particular case, dendrimers and other structures of chemistry have been attributed to some graphs, where by studying their graphical parameters, like connectivity, independent sets, perfect matchings, isomorphism and topological indices and other parameters, we obtain some results in chemistry  

    A magnetic multifunctional dendrimeric coating on a steel fiber for solid phase microextraction of chlorophenols

    , Article Microchimica Acta ; Volume 184, Issue 7 , 2017 , Pages 2201-2209 ; 00263672 (ISSN) Bagheri, H ; Manouchehri, M ; Allahdadlalouni, M ; Sharif University of Technology
    Springer-Verlag Wien  2017
    A polyamidoamine dendrimer was synthesized, placed on magnetite nanoparticles, and the resulting material was then employed as a fiber coating for use in solid phase microextraction of chlorophenols. The polyamidoamine was expected to be an efficient extracting medium due to the presence of multipolar groups and its inner porosity. A thin stainless steel wire was coated with the dendritic polyamidoamine polymer via electrolysis and chemical reactions. The coated fiber was investigated in terms of headspace solid phase microextraction of chlorophenols from aqueous samples followed by GC-MS quantitation. The calibration plots are linear in the 2–1000 ng⋅L−1 chlorophenol concentration ranges.... 

    Fabrication and characterization of high-branched recyclable PAMAM dendrimer polymers on the modified magnetic nanoparticles for removing naphthalene from aqueous solutions

    , Article Microchemical Journal ; Volume 145 , 2019 , Pages 767-777 ; 0026265X (ISSN) Aliannejadi, S ; Hassani, A. H ; Panahi, H. A ; Borghei, S. M ; Sharif University of Technology
    Elsevier Inc  2019
    In this study, magnetic nanoparticles (MNPs) modified with poly amidoamine (PAMAM) dendrimers - by adding methyl acrylate and ethylenediamine continuously till 10th generation- which further anchored to benzaldehyde ligand through polymeric bonding and studied as a novel method for synthesizing a nano sorbent for removing naphthalene (NAP) from aqueous environments. Synthesized nanopolymer was characterized by Fourier transform infrared spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FE-SEM) equipped with EDS, X-ray Diffraction (XRD), Vibrating Sample Magnetometry (VSM), thermal gravimetric analysis (TGA). Based on the obtained analysis results synthesized average... 

    Embryonic stem cells maintain an undifferentiated state on dendrimer-immobilized surface with D-glucose display

    , Article Polymers ; Volume 3, Issue 4 , 2011 , Pages 2078-2087 ; 20734360 (ISSN) Mashayekhan, S ; Kim, M. H ; Kino Oka, M ; Miyazaki, J. I ; Taya, M ; Sharif University of Technology
    In serial passaging cultures of mouse embryonic stem (ES) cells, we employed a dendrimer-immobilized substrate that displayed D-glucose as a terminal ligand. The D-glucose-displaying dendrimer (GLU/D) surface caused the ES cells to form loosely attached spherical colonies, while those on a gelatin-coated surface formed flatter colonies that were firmly attached to the surface. Despite the morphological similarities between the colonies on the GLU/D surface and aggregates on a conventional bacteriological dish, immunostaining and RT-PCR analyses revealed the maintenance of cells within the spherical colonies on the GLU/D surface in an undifferentiated state with very low expressions of... 

    Synthesis of new electromagnetic nanocomposite based on modified Fe3O4 nanoparticles with enhanced magnetic, conductive, and catalytic properties

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 65, Issue 8 , 2016 , Pages 384-390 ; 00914037 (ISSN) Pourjavadi, A ; Doroudian, M ; Afshar Saveh, Z ; Doulabi, M ; Sharif University of Technology
    Taylor and Francis Inc  2016
    A new method for the fabrication of an electromagnetic nanocomposite based on Fe3O4 and polyaniline (PANI) is offered. The authors focused on improvement of the physical and electromagnetic properties of the nanocomposite using a new synthetic method. Supermagnetic Fe3O4 nanoparticles were synthesized through coprecipitation method. As a chemical modification, the third generation of poly (amidoamine) dendrimer was grafted on the surface of the nanoparticles. PANI was grafted from -NH2 functional groups of dendrimer via in situ polymerization of aniline. Finally, Au nanoparticles were loaded on the nanocomposite and its catalytic activity for reduction reactions was studied  

    Magnetic pH-responsive nanocarrier with long spacer length and high colloidal stability for controlled delivery of doxorubicin

    , Article Colloids and Surfaces B: Biointerfaces ; Vol. 116 , April , 2014 , pp. 49-54 ; ISSN: 09277765 Pourjavadi, A ; Hosseini, S. H ; Alizadeh, M ; Bennett, C ; Sharif University of Technology
    A novel magnetic nanocarrier with long spacer length and high colloidal stability has been prepared for effective delivery of doxorubicin (DOX). First, poly(amidoamine) (PAMAM) dendrimer was grown up onto the surface of superparamagnetic iron oxide nanoparticles to increase the loading amount of amine groups. Then, terminal amine groups were functionalized by polyethylene glycol dimethylester to increase the spacer length. Then anticancer drug DOX was covalently attached onto the system by hydrazone bond to forms a pH-sensitive nanocarrier. This system is designed to combine the advantage of magnetic targeting, high drug loading capacity, and controlled release  

    Synthesis of poly(amidoamine)-graft-poly(methyl acrylate) magnetic nanocomposite for removal of lead contaminant from aqueous media

    , Article International Journal of Environmental Science and Technology ; Volume 13, Issue 10 , 2016 , Pages 2437-2448 ; 17351472 (ISSN) Pourjavadi, A ; Abedin Moghanaki, A ; Hosseini, S. H ; Sharif University of Technology
    Center for Environmental and Energy Research and Studies  2016
    Poly(amidoamine)-graft-poly(methyl acrylate) magnetic nanocomposite was synthesized via radical polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the functionalization of the methyl ester groups with poly(amidoamine) dendrimer. The resulting poly(amidoamine)-graft-poly(methyl acrylate) magnetic nanocomposite was then characterized by infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, scanning electron microscope and X-ray diffraction analysis. Its application as an adsorbent for the removal of Pb(II) ions was studied. The removal capability of the adsorbent was investigated in different pH values, contact time (kinetics) and... 

    Synthesis and Characterization of Properties of Hybrid Nanoparticles of Gold-graphene

    , M.Sc. Thesis Sharif University of Technology Akhoondi, Soheila (Author) ; Simchi, Abdolreza (Supervisor)
    In recent years utilization of quantum dots for stem cells detection and clean energy production has received intensive attention. Graphene and its derivatives have been widely studied because of their effectiveness on electronical and optoelectronical devices, chemical sensors, nanocomposites, and energy storage. By use of metal nanoparticles, such as AuNPs, we can develop properties of graphene, and control them via shifting the absorption peak wavelength and increasing its biocompatibility. In this research, hybrid nanoparticles of gold-graphene as core-shell and conjugated by polymeric linkers containing amine or thiol functions are synthesized. Our purpose is stabilization the... 

    Synthesis of water dispersible reduced graphene oxide via supramolecular complexation with modified β-cyclodextrin

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 66, Issue 5 , 2017 , Pages 235-242 ; 00914037 (ISSN) Pourjavadi, A ; Eskandari, M ; Hosseini, S. H ; Nazari, M ; Sharif University of Technology
    Taylor and Francis Inc  2017
    A noncovalent functionalization of the edges of reduced graphene oxide (RGO) with β-cyclodextrin-graft-hyperbranched polyglycerol (β-CD-g-HPG) was successfully performed via a host-guest interaction. The results showed that β-CD-g-HPG disperses the graphene sheets better than pure β-CD or HPG. The resulted supramolecular structure is stable in neutral water medium more than one week. However, in acidic medium the host-guest interaction is collapsed and graphene nanosheets precipitate. © 2017, Copyright © Taylor & Francis  

    Globular structure of ZA27 alloy by thermomechanical and semi-solid treatment

    , Article Materials Science and Engineering A ; Volume 391, Issue 1-2 , 2005 , Pages 77-85 ; 09215093 (ISSN) Aashuri, H ; Sharif University of Technology
    The dendritic structure of a cast ZA27 alloy can be transformed into a globular structure, if it is cold worked prior to being held in a semi-solid condition. The globular or the equiaxed particles are surrounded by the lower melting matrix. The dendritic structure was swaged and recrystallised prior to holding in a semi-solid state in this investigation. The semi-solid holding of the alloy at temperatures above and below that of peritectic reaction was carried out for various lengths of time. It was shown that the liquid fraction is decreased to below the peritectic temperature which leads to a reduction of lubrication between the solid globules and an increasing deformation force. Holding... 

    Nanomagnetic Polyamidoamine Dendrimer as A Novel Sorbent for Solid Phase Microextraction of Chlorophenols from Aquatic Media

    , M.Sc. Thesis Sharif University of Technology Manouchehri, Mahshid (Author) ; Bagheri, Habib (Supervisor)
    In this study, ananomagnetic polyamidoamine (PAMAM) dendrimer was synthesized as a novel SPME fiber coating and implemented to the determination of traces of chlorophenols in water samples. The synthesized magnetic PAMAM shows to have many polar groups with an enhanced internal porosity which is promising to be used as an efficient extracting medium. With this purpose, a thin stainless steel wire was coated by the network of dendritic PAMAM polymer through electrolysis and chemical reactions. The synthesized fiber is physical stable since it was chemically bonded to the substrate. Extraction efficiency of new coating was investigated by headspace SPME of chlorophenols from aqueous samples... 

    Design of Drug Nanocarriers Based on Mesoporous Silica Nanoparticles Coated with Smart Polymers

    , Ph.D. Dissertation Sharif University of Technology Mazaheri Tehrani, Zahra (Author) ; Pourjavadi, Ali (Supervisor)
    Mesoporous silica nanoparticles have broad application in drud delivery systems due to their porous structure, functionalization, biocompatibility, high surface area and pore volume. Neverthless, pure mesoporous silica nanoparticles without functionality were not smart material and could not release drug in triggered and controlled manner. For this reason, using smart polymeric coating would be considered. Polymer shells also provide colloidal stability, improved blood circulation lifetime and reduced toxicity which are crucial for efficient in vivo drug delivery. Inflammatory and tumor tissue have low pH and high temperature as compared to health tissue. Therefore, using pH and... 

    Synthesis of Magnetic Nanocarriers Based on Coating of Fe3O4 with Modified Biodegradable Polysaccharides by pH Sensitive Agents for Targeted Release of Anticancer Drug Doxorubicin

    , M.Sc. Thesis Sharif University of Technology Amin, Shiva Sadat (Author) ; Pourjavadi, Ali (Supervisor)
    One of the major problems in cancer treatment is the side effects of the drugs. Nowadays, scientists are developing smart nanocarriers which used for diagnosis and delivering drugs in order to circulate through blood vessels, pass the immune system, attach to cancer cells and kill them without any side effects. In the first research of this thesis, magnetic nanoparticles were coated by modified alginate and used as smart nanocarriers. Magnetic nanocarrier were sysnthesized based on hydrophobic coating of oleic acid and hydrazine oleate-modified alginate shell. The resulting carrier is pH-sensitive and the alginate shell removes in the low pH medium. DOX was placed between hydrophobic chains.... 

    Hybrid nanomaterials containing PAMAM, polyrotaxane and quantum dot blocks

    , Article Nano ; Volume 6, Issue 3 , June , 2011 , Pages 239-249 ; 17932920 (ISSN) Adeli, M ; Sarabi, R. S ; Sadeghi, E ; Sharif University of Technology
    Pseudopolyrotaxanes, Ps-PR, consisting of α-cyclodextrin rings, polyethylene glycol axes and end triazine groups were prepared and then were capped by amino-functionalized quantum dots, NH 2-QDs, to achieve polyrotaxanes. The amino-functionalized QDs stoppers of polyrotaxanes were used as core to synthesize polyamidoamine, PAMAM, dendrons divergently and hybrid nanomaterials were obtained. Synthesized hybrid nanomaterials were characterized by different spectroscopy, microscopy and thermal analysis methods. They were freely soluble in water and their aqueous solutions were stable at room temperature over several months. Due to their biocompatible backbone, high functionality and water...