Sharif Digital Repository

To synthesize a novel biopolymer-based superabsorbent hydrogel, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) was grafted onto kappa-carrageenan (KC) backbones. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator, N,N,N',N'-tetramethyl ethylenediamine (TMEDA) as an accelerator, and N,N'-methylene bisacrylamide (MBA) as a crosslinker. A proposed mechanism for KC-g-AMPS formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy. The affecting variables on swelling capacity, i.e., the initiator, the crosslinker, and the monomer concentration, as well as reaction temperature,... 

A novel pH-responsive superabsorbing hydrogel based on κ-carrageenan (κC) was prepared through polyacrylamide crosslinking grafting followed by alkaline hydrolysis. The hydrogel structure was confirmed using FT-IR spectroscopy. The hydrolysis conditions were systematically optimized to obtain a hydrogel with maximum swelling capacity. Thus, the reaction variables, including the hydrolysis time and temperature, concentration of sodium hydroxide, amount of hydrogel hydrolyzed and post-neutralization pH, were optimized. The swelling measurements of the hydrogels were conducted in 0.15 M aqueous solutions of LiCl, NaCl, KCl, CaCl2 and AlCl3. As observed for the hydrolyzed hydrogel (H-carragPAM),... 

A novel, magnetic nanocarrier was successfully synthesized through a facile and economical producer in which Fe3O4 magnetic nanoparticles were coated by starch-g-poly (methyl methacrylate-co-PEG-acrylamide). The surface of nanocarrier was then modified by hydrazine to preparation of a pH-responsive carrier. The resulted nanocarrier was applied for delivery of doxorubicin (DOX) as an effective anti-cancer drug. DOX was reacted with hydrazine linkage on the surface of nanocarrier to form hydrazone bond. Due to the presence of numerous hydrazine groups on the surface of magnetic nanocarrier large amounts of DOX was loaded onto the carrier (327 mg g−1). © 2016 The Korean Society of Industrial... 

In this paper, synthesis and swelling behavior of a novel superabsorbent hydrogel based on kappa carrageenan (κC) and polyacrylonitrile (PAN) was investigated. To achieve partially hydrolyzed κC-PAN hydrogel, physical mixture of κC and PAN was hydrolyzed by NaOH solution. During alkaline hydrolysis, the nitrile groups of PAN are converted to a mixture of hydrophilic carboxamide and carboxylate groups follow by in situ crosslinking of the grafted PAN chains. The reaction variables affecting on the swelling capacity of the hydrogel were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. Under the optimized conditions concluded, super swelling hydrogel... 

To synthesize a novel biopolymer-based superabsorbent hydrogel, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) was grafted onto kappa-carrageenan (ΚC) backbones. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator, N,N,N′,N′-tetramethyl ethylenediamine (TMEDA) as an accelerator, and N,N′-methylene bisacrylamide (MBA) as a crosslinker. A proposed mechanism for ΚC-g-AMPS formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy. The affecting variables on swelling capacity, i.e., the initiator, the crosslinker, and the monomer concentration, as well as reaction temperature,... 

In this study synthesis of a drug delivery system (DDS) is described which has several merits over its counterparts. In order to synthesize this nano-carrier, graphene oxide nano-sheets are used to accommodate MCM-41 nanoparticles. Furthermore Fe3O4 nanoparticles are introduced to this nano-material to produce a traceable nanoparticle. Since cancerous tissues have lower pH than healthy tissues, pH-sensitive oligomers are attached to this nano-material. Finally the nano-carrier is wrapped by a biocompatible shell (PEGylated sodium alginate); this polymeric shell makes the DDS capable of a more controllable drug release. By measuring in vitro situation, ‘loading content%’... 

Novel bilayer coated mesoporous silica nanoparticle (MCM-41) based on pH sensitive poly(acrylic acid-co-itaconic acid) and human serum albumin (HSA) was designed for controlled delivery of gemcitabine (anticancer drug) to cancer cells. The shell around the mesoporous silica has bilayer structure. Poly(acrylic acid-co-itaconic acid) was used as pH-sensitive inner shell and human serum albumin, HSA, was used as outer shell. The core-shell structure was formed due to electrostatic interaction between ammonium groups of modified MCM-41 and carboxylate groups of copolymer. Also, the albumin layer was wrapped around the copolymer coated nanoparticle by electrostatic interaction between ammonium... 

A novel nanocarrier based-on hollow mesoporous carbon nanospheres (HMCNs) with primary amines on its surface, a large cavity, and good hydrophilicity was synthesized by a hydrothermal reaction. The primary amine functionalities on the mesoporous carbon were used as the initiation sites for growing poly (epichlorohydrin) (PCH) chains. The chlorine groups in the side chain of PCH were replaced with imidazole as the pendant groups. Calcium chloride (CaCl2) was applied as a capping agent. The coordination bonding was formed between pendant imidazole groups and calcium ions. Doxorubicin (DOX) was selected as a model of hydrophilic anticancer drug and was loaded onto the nanocarrier and released... 

Multistimuli-responsive hyperbranched polymers were synthesized in one-step polymerization using reversible addition-fragmentation chain transfer self-condensing vinyl polymerization (RAFT-SCVP). These hyperbranched polymers responded to UV-vis or sunlight, pH changes, and temperature changes. 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid known as DDMAT participated in esterification with 2-hydroxyethyl methacrylate to obtain a chain transfer monomer in the name of 2-((2-(((dodecylthio)carbonothioyl)thio)-2-methylpropanoyl)oxy)ethylmethacrylate (MACDT). For the first time, smart hyperbranched polymers were produced with the RAFT-SCVP method in one step by using... 

Developing chemical sensors with pronounced sensitivity towards lanthanides is a very important task related to the analytical control of industrial processes in nuclear industry. Various diamides of organic acids were shown to be very effective for such sensing applications when employed as ligands in plasticized polymeric membranes of potentiometric sensors. The chemical structures of some of these ligands (diamides of diglycolic acid) are very similar to those suggested in 80’s as Ca(II) ionophores that were later commercialized. We have hypothesized that commercial ionophores ETH 129 (N,N,N′,N′-tetra[cyclohexyl] diglycolic acid diamide) and ETH 5234... 

This work describes the preparation of magnetic and pH-sensitive beads based on κ-carrageenan and sodium alginate for use as drug-targeting carriers. Physical cross-linking using K+/Ca2+ ions was applied to obtain ionic cross-linked magnetic hydrogel beads. The produced magnetite beads were thoroughly characterized by TEM, SEM/EDS, XRD, FTIR, and VSM techniques. While the water absorbency (WA) of magnetic beads was enhanced by increasing the weight ratio of κ-carrageenan, introducing magnetic nanoparticles caused a decrease in WA capacity from 15.4 to 6.3 g/g. Investigation on the swelling of the hydrogel beads in NaCl, KCl, and CaCl2 solutions revealed the disintegration of beads depending... 

In this research, we report a magnetic pH-sensitive polymeric micelle designed for hydrophobic drug carrier in cancer treatment. This carrier was prepared by self-assembly of biodegradable triblock copolymer PEG-PCL-PEG coated on oleate-modified magnetic nanoparticles. The amphiphilic triblock copolymer was synthesized via reaction between the aldehyde group from the hydrophilic component with the amine group of the hydrophobic component. The resulting Schiff base linkage was sensitive to pH. The structure of nanocarrier was characterized by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H-NMR). Morphology and size of the magnetic... 

In this work, a novel carrier based-on modified graphene oxide was designed for co-delivery of hydrophobic and hydrophilic anticancer drugs (curcumin (Cur) and doxorubicin (DOX) as the model of drugs). The hydroxyl groups at the edges of graphene oxide (GO) sheets were used as the initiation sites for growing poly(epichlorohydrin) (PCH) chains. Then, hyperbranched polyglycerol (HPG) was grafted on the hydroxyl end groups of PCH (PCH-g-HPG). Pendant chlorines in the main chain of GO-PCH-g-HPG were replaced with hydrazine. The modification of GO sheets with oxygen-rich polymers increased water solubility of graphene oxide. Doxorubicin was loaded onto the nanocarrier by covalent bonding with... 

Herein, the facile and tunable technique for the preparation of novel multi-stimuli-responsive nanocomposites via RAFT polymerization for DOX delivery is reported. The influence of the molecular weight of pH- and thermo-sensitive poly (acrylic acid-co-NIPAM) (PNAx), as a macro-RAFT agent, on the nanocomposites size and drug release rate was investigated. The outcome of this study reveals that macro-RAFT agent with lower molecular weight can be attached to the surface of magnetic nanoparticles with higher content of polymeric layer than can macro-RAFT agent with higher molecular weight. Also, it was observed that the particle size, polymer grafting density, DOX loading capacity, and DOX...