Synthesis of polyvinyl alcohol hydrogel grafted by modified Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles: characterization and doxorubicin delivery studies

During the last two decades, serious efforts have been directed towards the synthesis and coating magnetic nanoparticles for biomedical applications. Among many different types of polymeric coating materials that have been utilized in previous studies, we have selected polyvinyl alcohol (PVA). In this study, we report a novel type of magnetite nanocomposite-based PVA hydrogel. For this purpose, first, Fe₃O₄ nanoparticles were modified through hexamethylene diisocyanate (HMDI) and then PVA was modified by bromoacetyl bromide to produce bromoacetylated PVA. The modified PVA was cross-linked through various diamines such as ethylene-diamine, propylene-diamine and hexamethylenediamine. The prepared weak tridimensional PVA hydrogels were further reacted through unreacted hydroxyl groups with Fe₃O₄, modified by HMDI to form magnetite hard tridimensional hydrogels. The swelling behavior of the prepared magnetite nanocomposites were investigated and showed a fast initial swelling followed by a mild increase until attaining equilibrium. The structural, morphological, thermal and magnetic properties of the synthesized magnetite nanocomposites were confirmed by FTIR, thermal gravimetric analysis, vibrating sample magnetometer and scanning electron microscopy. The doxorubicin anti-tumor drug was loaded on a selected synthesized magnetic hydrogel and in vitro drug release studies were done in phosphate buffer solution in 37 °C.     

A Novel Stimuli-Responsive Magnetite Nanocomposite as De Novo Drug Delivery System

A novel stimuli-responsive magnetite nanocomposite as de novo drug delivery system for cancer chemotherapy is developed successfully through the incorporation of magnetite nanoparticles into PEG-b-(PNIPAAm-b-PAA)₂ copolymer. The chemical structures of samples were characterized using FTIR and ¹H NMR spectroscopies. Furthermore, thermal property, morphology, size, and magnetic properties of the nanocomposite were investigated. The DOX loading and encapsulation efficiencies as well as stimuli-responsive drug release ability of the nanosystem were studied. As results, at pH 5.3 and temperature of 41°C the nanocomposite exhibited higher drug release values, which qualified it for cancer chemotherapy according to especial features of cancerous tissue.     

Sulfonic Acid-Functionalized Fe3O4 Reinforced Soluble Polyimide: Synthesis and Properties

In this study, a series of nanocomposite films based on an aromatic polyimide and sulfonic acid-functionalized magnetic nanoparticles was successfully prepared via an in situ technique. For this purpose, new soluble aromatic polyimide containing sulfone group as a polymeric matrix of the nanocomposites was synthesized. The surfaces of MNP were grafted with 3-mercaptopropyl trimethoxysilane. Then sulfonic acid-functionalized magnetic nanoparticle was obtained by oxidation of the thiol group. Effects of sulfonic acid-functionalized magnetic nanoparticles on thermal, tensile, and magnetic properties of the prepared nanocomposite films were studied. The magnetic nanoparticles containing the sulfonic acid groups could have strong intermolecular bond interactions between the hydroxyl groups of SO₃H and the sulfone and carbonyl groups of the polyimide matrix which caused the better dispersion of nanoparticle and exhibited superior mechanical properties, good magnetic properties, and high thermal stability.     

One-pot synthesis of amphiphilic nanogels from vinylated SPIONs/HEMA/PEG via a combination of click chemistry and surfactant-free emulsion photopolymerization: Unveiling of the protein-nanoparticle interactions

In this study, freshly prepared Fe₃O₄ nanoparticles (MNP1) were coated with 3-aminopropyltriethoxysilane (APTES) to produce core–shell Fe₃O₄@SiO₂ nanoparticles (MNP2), amine terminated nanoparticles was converted into the triazide in the presence of as-prepared triflic azide (MNP3). Propargyl acrylate (PgA) was synthesized from propargyl alcohol and acryloyl chloride and their structures were characterized by FT-IR and ¹H NMR spectroscopy. MNP3 were modified by PgA via click reaction to produce fully decorated triazole product (MNP4). Photopolymerization of MNP4 in the presence of hydroxyethyl methacrylate (HEMA) and acrylated methyl ether poly (ethylene glycol) (ACMPEG) were carried out by emulsion method without any surfactant (MNP5). The in-vitro release behavior of quercetin from MNP5s was investigated at two pHs (7.4 and 5.8). The effect of fetal bovine serum (FBS) on MNPs and its ability to cover magnetite nanoparticles was investigated.     

Efficient Dispersion of Magnetite Nanoparticles in the Polyurethane Matrix Through Solution Mixing and Investigation of the Nanocomposite Properties

Recent studies on inorganic/polymer nanocomposites have shown enhancements in thermal, mechanical, and chemical properties over the neat polymer without compromising density, toughness, and processibility. When nanoparticles are incorporated into the polymer matrix, significant enhancements in thermal and mechanical properties of the nanocomposite are observed. The present study is focused on the preparation and characterization of nanosize magnetite-reinforced PU composites, which induces magnetic properties to a specific thermoplastic polyurethane elastomer. The nanocomposites are prepared and the effects of magnetite content on thermal, mechanical, and magnetic properties of the nanocomposites are evaluated. Ultrasonication was used to disperse the nanoparticles and break up any large clumps and aggregates and followed by mechanical mixing. The magnetic nanocomposites were characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). Characterization of the magnetic nanocomposite by FT-IR showed a successful incorporation of magnetite nanoparticles into the polymeric matrix. TGA and magnetometry of the magnetic nanocomposites revealed the amount of magnetite that was incorporated into the polymeric phase. Finally, the corresponding magnetization behavior of the nanocomposites was studied.     

Embedded of Nanogel into Multi-responsive Hydrogel Nanocomposite for Anticancer Drug Delivery

Hydrogels, nanogels, and nanocomposites show increasing potential for application in drug delivery systems due to their good chemical and physical properties. Therefore, we were encouraged to combine them to produce a new compound with unique properties for drug release systems. To this aim, we first prepared poly [(N-isopropylacrylamide)-co-(2-dimethylamino ethyl methacrylate) nanogel by copolymerization processes and then added it into the solution of poly (2-dimethylamino ethyl methacrylate)] grafted onto salep. Through dropwise addition of mixed aqueous solution of iron salts into the prepared polymeric solution, a novel hydrogel nanocomposite with excellent pH, thermo, and magnetic responsive was fabricated. The obtained hydrogel nanocomposite were characterized by Fourier transform infrared spectroscopy, thermo gravimetric analysis, X-ray diffraction, scanning electron microscopy, vibrating sample magnetometer, and atomic force micrographs. The dependence of swelling properties of hydrogel nanocomposite on the temperature, pH, and magnetic field were investigated. The release behavior of doxorubicin hydrochloride (DOX) drug from DOX loaded into synthesized hydrogel nanocomposite was investigated at different pHs, temperatures, and magnetic field. In addition, the drug release behavior from obtained hydrogel nanocomposite was monitored via different kinetic models. Lastly, the toxicity of the DOX and DOX-loaded hydrogel nanocomposite were studied on MCF-7 cells at different times. These results suggested that the obtained hydrogel nanocomposite might have high potential applications in drug delivery systems.     

Temperature/pH/magnetic triple‐sensitive nanogel–hydrogel nanocomposite for release of anticancer drug

Hydrogels, nanogels and nanocomposites show increasing potential for application in drug delivery systems due to their good chemical and physical properties. Therefore, we were encouraged to combine them to produce a new compound with unique properties for a long‐term drug release system. In this regard, the design and application of a nanocomposite hydrogel containing entrapped nanogel for drug delivery are demonstrated. To this aim, we first prepared an iron oxide nanocomposite nanogel based on poly(N‐isopropylacrylamide)‐co‐((2‐dimethylaminoethyl) methacrylate) (PNIPAM‐co‐PDMA) grafted onto sodium alginate (NaAlg) as a biocompatible polymer and iron oxide nanoparticles (ION) as nanometric base (PND/ION‐NG). This was then added into a solution of PDMA grafted onto NaAlg. Through dropwise addition of mixed aqueous solution of iron salts into the prepared polymeric solution, a novel hydrogel nanocomposite with excellent pH, thermal and magnetic responsivity was fabricated. The synthesized samples were fully characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy with energy‐dispersive X‐ray analysis, vibrating sample magnetometry and atomic force microscopy. A mechanism for the formation of PNIPAM‐co‐PDMA/NaAlg‐ION nanogel–PDMA/NaAlg‐ION hydrogel and PND/ION nanogel is suggested. Swelling capacity was measured at various temperatures (25 to 45 °C), pH values (from 2 to 11) and magnetic field and under load (0.3 psi) and the dependence of swelling properties of the nanogel–hydrogel nanocomposite on these factors was well demonstrated. The release rate of doxorubicin hydrochloride (DOX) as an anticancer drug was studied at different pH values and temperatures in the presence and absence of a magnetic field. The results showed that these factors have a high impact on drug release from this nanocomposite. The result showed that DOX release could be sustained for up to 12.5 days from these nanocomposite hydrogels, significantly longer than that achievable using the constituent hydrogel or nanogel alone (<1 day). The results indicated that the nanogel–hydrogel nanocomposite can serve as a novel nanocarrier for anticancer drug delivery. © 2019 Society of Chemical Industry     

Anti-neoplastic Applications of Heparin Coated Magnetic Nanoparticles Against Human Ovarian Cancer

This study determines the effect of bare and heparin (HP)-based magnetic iron oxide (Fe₃O₄) nanoparticles (MNPs) on the human ovarian cancer cells of CP70 type. Cisplatin (CP) was used as the anticancer drug, entrapped in MNPs. The nanoparticles containing the anticancer drug, CP, were prepared by a solvent evaporation and emulsification cross-linking method. The physicochemical properties of the nanoparticles were characterized by various techniques, and uniform particles of bare and HP coated MNPs, with average particle sizes of 25 and 45 ± 15 nm, having high encapsulation efficiencies, were obtained. Additionally, a sustained release of CP from the MNPs was successful in vitro. Cytotoxicity tests showed that the MNP–HP–CP had higher cell toxicity than the individual HP; and confocal microscopic analysis confirmed excellent cellular uptake efficiency of CP70 cells for MNP–HP–CP. These results indicate that HP based MNPs have potential uses as anticancer drug carriers and have also proved to have enhanced anti-neoplastic effects.     

Nanocomposite particles with core‐shell morphology. I. Preparation and characterization of Fe3O4–poly(butyl acrylate‐styrene) particles via miniemulsion polymerization

Colloidal particles with magnetic properties have become increasingly important both technologically and for fundamental studies. Here, chemical initiator‐free miniemulsion polymerization of styrene and butyl acrylate has been performed for preparation of magnetic nanocomposite particles with the diameter of 81–150 nm in the presence of sodium dodecyl sulfate as surfactant, span 80 as stabilizer, and hexadecane as hydrophobe. The polymerization reaction was initiated and progressed under ultrasonic irradiation, generated by immersed probe into the latex. The key point in achievement of encapsulation of modified Fe₃O₄ nanoparticles was preparation of a stable colloidal dispersion at the end of the reaction. The obtained products in each step were characterized by FTIR spectroscopy. Dynamic light scattering analysis was used to follow particle size diameter of the samples. Morphology of the particles and formation of core‐shell structure were analyzed by SEM and TEM micrographs, respectively. TGA and magnetometry of the polymeric films confirmed the extent of insertion of used magnetite and their corresponding behavior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Contributions of TMAH Surfactant on Hierarchical Structures of PVA/Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>–TMAH Ferrogels by Using SAXS Instrument

The magnetic hydrogels combining polyvinyl-alcohol (PVA) and Fe₃O₄ (magnetite)–TMAH (tetra-methyl ammonium hydroxide) have been successfully fabricated via a Freezing-thawing route. The magnetite nanoparticles were prepared from iron sands by using coprecipitation method. The transmission electron microscopy image revealed that the magnetite nanoparticles with a reaction temperature of 30 °C had the average particle size of 12 nm in clusters of aggregation. The result was similar to the particle size obtained from X-ray diffraction data analyzed by Scherer equation. Furthermore, synchrotron small angle X-ray scattering data were analyzed by using two lognormal distributions to calculate the distribution of the individual magnetite particles. Meanwhile, Teubner-Strey and Beaucage models were employed to observe the distribution of magnetite particles coated by TMAH as a surfactant. The data analysis showed that the magnetite particles within the magnetic hydrogels formed aggregations with diameters of cluster particles in the range from 13.1 to 31.8 nm. Interestingly, the diameter of clusters particle increased from 13.1 to 31.8 nm along with the increasing concentration of ferrofluids from 1 to 15 wt%. This phenomenon was predicted to result from the effect of TMAH as a surface reactant agent that prevented the aggregation by coating the surface of the magnetite nanoparticles.     

Titania-Coated Magnetite and Ni-Ferrite Nanocomposite-Based RADAR Absorbing Materials for Camouflaging Application

A novel core–shell-structured nanocomposite material based on titanium dioxide-coated magnetite and Ni-ferrite has been prepared for RADAR absorbing application in a X-band region. The coating of magnetic particles with TiO₂ was carried out by in situ hydrolysis of titanium tetrabutoxide, and the composite absorber sheets were prepared with epoxy resin. The morphological characterization of the magnetic particles was studied with field emission scanning electron microscope, transmission electron microscope, X-ray diffraction, and vibrating sample magnetometer analysis techniques. The measurement results confirmed the coating of magnetic particles with TiO₂ and reduction of the magnetization of magnetite and Ni-ferrite nanoparticles compared with the uncoated ferrite nanoparticles. Distribution of particle inside the matrix was studied with scanning electron microscope. Microwave absorption study in X-band (8–12 GHz) region was carried out with vector network analyzer. Results showed reflection loss values of ?26.5 db at 9.08 GHz for the magnetite coated with titanium dioxide/conducting carbon black containing sample which increased to ?45.7 db at 9.13 GHz for the Ni-ferrite coated with TiO₂/conducting carbon black formulation. It was observed that coating of magnetic particles resulted in the improvement in the microwave absorption.     

Synthesis of core-shell gold coated magnetic nanoparticles and their interaction with thiolated DNA

Core-shell magnetic nanoparticles have received significant attention recently and are actively investigated owing to their large potential for a variety of applications. Here, the synthesis and characterization of bimetallic nanoparticles containing a magnetic core and a gold shell are discussed. The gold shell facilitates, for example, the conjugation of thiolated biological molecules to the surface of the nanoparticles. The composite nanoparticles were produced by the reduction of a gold salt on the surface of pre-formed cobalt or magnetite nanoparticles. The synthesized nanoparticles were characterized using ultraviolet-visible absorption spectroscopy, transmission electron microscopy, energy dispersion X-ray spectroscopy, X-ray diffraction and super-conducting quantum interference device magnetometry. The spectrographic data revealed the simultaneous presence of cobalt and gold in 5.6±0.8 nm alloy nanoparticles, and demonstrated the presence of distinct magnetite and gold phases in 9.2±1.3 nm core-shell magnetic nanoparticles. The cobalt-gold nanoparticles were of similar size to the cobalt seed, while the magnetite-gold nanoparticles were significantly larger than the magnetic seeds, indicating that different processes are responsible for the addition of the gold shell. The effect on the magnetic properties by adding a layer of gold to the cobalt and magnetite nanoparticles was studied. The functionalization of the magnetic nanoparticles is demonstrated through the conjugation of thiolated DNA to the gold shell.     

Synthesis and characterization of a novel pH-responsive nanocomposite hydrogel based on chitosan for targeted drug release

Over the last decade, nanocomposite hydrogels have been provided a new approach for the biomedical field. In this work, a novel pH-responsive nanocomposite hydrogel was fabricated using simultaneous in situ formation of magnetite iron oxide nanoparticles and hydrogel networks of poly(acrylic acid) grafted onto chitosan. The effects of various types of precursor molecules, pH, salt, and loading pressure were examined on the swelling properties of resulting nanocomposite hydrogels. The synthesized nanocomposite hydrogel was well characterized using different instruments. In vitro drug releasing behavior of doxorubicin was studied at pH 5.4 and 7.4. The drug release mechanism was investigated through different kinetic models. These experimental results open a new opportunity to make pH-responsive nanocomposite hydrogel devices for controlled delivery of drug.     

Phosphate glasses containing monodisperse Fe3−δO4@SiO2 stellate nanoparticles obtained by melt-quenching process

The challenge to obtain stable glasses containing monodisperse magnetic nanoparticles with controlled size and shape is an exciting and almost unexplored field of research. Such new materials can be used in magneto-photonics or ultra-sensitive magnetic sensors. In this work, for the first time, colorless and transparent bulk glasses containing monodisperse 20 nm Fe_3−δO₄ nanoparticles were prepared by a melt-quenching route. Magnetic nanoparticles were synthesized by thermal decomposition and covered with a stellate mesoporous silica shell in order to protect them against dissolution during the glass melting process. The incorporation of nanoparticles into glasses and the ideal parameters obtained for this system are discussed. The new nanocomposite materials were characterized in order to investigate the structure, thermal, and magnetic properties. Such an original approach is a very promising way to incorporate a wide panel of nanoparticles, including metallic, bimetallic and metal oxide nanoparticles, into a variety of glasses providing new properties to these materials.     

Size Controlling of L1<Subscript>0</Subscript>-FePt Nanoparticles During High Temperature Annealing on the Surface of Carbon Nanotubes

Mono-size FePt nanoparticles with particles size about 2.5 nm have been prepared by polyol method on the surface of carbon nanotubes (CNTs). The CNTs functinalization time and the mass ratio of nanoparticles to CNTs affects on the CNTs surface coating. The as-synthesis nanocomposites have a superparamagnetic behavior with chemically disordered fcc structure at room temperature and they can be transformed into chemically ordered fct structure after thermal annealing above 600 °C. Their magnetic behavior changes from the superparamagnetic to the ferromagnetic with a large coercivity up to 0.83 T for the nanocomposites which annealed at 800 °C. The CNTs surfaces as a substrate prevent the agglomeration of nanoparticles during high temperature annealing and the FePt nanoparticles after annealing at 800 °C have finite size with an average about 10 nm. The structure, composition and magnetic properties of nanocomposite were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer.     

A magnetic polypeptide nanocomposite with pH and near-infrared dual responsiveness for cancer therapy

A magnetic polypeptide nanocomposite with pH and near-infrared (NIR) dual responsiveness was developed as a drug carrier for cancer therapy, which was prepared through the self-assembly of Fe₃O₄ superparamagnetic nanoparticles, poly(aspartic acid) derivative (mPEG-g-PDAEAIM) and doxorubicin (DOX) in water. Fe₃O₄ nanoparticles were prepared to provide the superparamagnetic core of nanocomposites for tumor targeting via chemical co-precipitation. The protonable imidazole groups of mPEG-g-PDAEAIM with a pKa of ~7 were accountable for the pH-responsiveness of nanocomposites. The photothermal effect of nanocomposites under the irradiation of NIR laser was induced via the interactions between dopamine groups of mPEG-g-PDAEAIM and Fe₃O₄ superparamagnetic nanoparticles to trigger the drug release. NMR, FT-IR, TEM, hysteresis loop analysis and MRI were utilized to characterize the materials. The DOX loaded nanocomposites exhibited pH-responsive and NIR dependent on/off switchable release profiles. The nanocomposites without drug loading (Fe₃O₄@mPEG-g-PDAEAIM) showed excellent biocompatibility while DOX loaded nanocomposites caused MCF-7 cells’ apoptosis due to the photothermal/chemotherapy combination effects. Overall, the pH and near-infrared dual responsive magnetic nanocomposite had a great potential for cancer therapy.     

Preparation and characterization of magnetite/dextran nanocomposite used as a precursor of magnetic fluid

Magnetic nanoparticles were synthesized by the co-precipitation of Fe²⁺ and Fe³⁺ using ammonium hydroxide (NH₄OH). The obtained nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer. In order to prepare a biocompatible water-based magnetic fluid, the nanoparticles were modified by dextran through a two-step method. The influences of dextran molecular weight on the size, morphology, coating efficiency and magnetic property of magnetite/dextran nanocomposite were investigated. The magnetite/dextran nanocomposite was dispersed in water to form a magnetic fluid by ball milling. The rheological property of magnetic fluids was investigated using a rotating rheometer.     

Preparation of shell crosslinked nanoencapsulate for drug carriers by using poly(N-isopropyl acrylamide)-co-poly(L-lysine) grafted copolymer

Shell crosslinked nanoencapsulate were prepared via crosslinking reaction between double hydrophilic grafted copolymers poly(N-isopropyl acrylamide)-co-poly(L-lysine) (PNIPAm-co-PLLys) and natural crosslinking agent genipin. These shell crosslinked nanoencapsulate possess spherical structures and the hydrodynamic radiuses are about 18.5 nm to 37.7 nm. Drug-loaded shell crosslinked nanoencapsulate were applied as drug carriers. Model drug methotrexate (MTX) were loaded into polymeric nanoencapsulate with different loading ratios (polymer / MTX?=?10 / 0.5 and 10 / 1.0), then crosslinking agent genipin was added into micelle solution to form drug-loaded shell crosslinked nanoencapsulate. Entrapment efficiency and drug loading content of the drug-loaded shell crosslinked nanoencapsulate are about 12.66 wt% to 20.1 wt% and 0.84 wt% to 1.28 wt%, respectively. In-vitro drug release experiments of drug-loaded shell crosslinked nanoencapsulate were carried out in pH 7.4 phosphate buffer solution at 37 °C. All of these samples possess burst release in initial 8 h, and final accumulate MTX release amounts are about 71% to 97%.     

Magnetic electrospun fluorescent polyvinylpyrrolidone nanocomposite fibers

Magnetic nanoparticles (MNPs) were synthesized from facile thermodecomposition of iron pentacarbonyl and the subsequent silica coating on the MNP surface was achieved via a modified Stöber process to obtain the core–shell composite structured particles (MNPs-SiO₂). MNPs-SiO₂ were then incorporated into polyvinylpyrrolidone (PVP) to form nanocomposite fibers via an electrospinning process with optimized operational parameters such as polymer concentration, applied electrical voltage, feed rate and tip-to-collector distance. All these parameters show an unusual effect on the produced fiber diameter. Contrary to the conventional observation, i.e., increasing the applied voltage and feed rate or decreasing the distance could increase the fiber diameter; a reduced average fiber diameter was observed in this study and could be explained from the stretching and contraction force balance within the fiber during electrospinning. The size of the resulting PVP fibers is correlated to the corresponding rheological behaviors of the PVP solutions with different concentrations. The MNPs-SiO₂/PVP nanocomposite fibers exhibit a similar thermal decomposition temperature (386.3 °C) as that (387.8 °C) of pure PVP. Meanwhile, unique fluorescent and magnetic properties have been incorporated simultaneously in the nanocomposite fibers with the addition of small amount of MNPs-SiO₂ nanoparticles.     

Smart magnetic self-assembled micelle: an effective nanocarrier for thermo-triggered paclitaxel delivery

Magnetic micelle nanoparticles with thermoresponsive behavior were designed for thermo-triggered paclitaxel delivery. For this purpose, thermoresponsive triblock copolymer poly(N-isopropyl acrylamide)-b-polycaprolactone-b-poly(N-isopropyl acrylamide) was prepared. The magnetic micelle was formed by self-assembly of triblock copolymer on the magnetite which was coated by oleic acid. The size of the magnetic micelle was between 30–40?nm reported by transmission electron microscopy. Also, dynamic light scattering indicated the hydrodynamic diameter was thermal dependent. Moreover, the drug release profile showed thermo-triggered release of paclitaxel. Thus, the smart nanocarrier has potential to be applied in both chemotherapy and hyperthermia treatment.