Hybrid Magnetic Particles Research Articles

An explorative study of biotin functionalized magnetic hybrid particles

In the field of biomedicine, magnetic particles have a significant role, owing to their low production cost and the possibility to control their characteristics, like size, shape and ability to tailor the cellular interactions, in order to promote their involvement in the development of novel therapies. Biofunctionalisation is by far, the most studied aspect, since it provides multifunctionality (e.g. increased biocompatibility and biodistribution, or cytotoxicity and toxic selectivity mechanisms). In this framework, this explorative study is devoted to development and characterization of the biotin functionalized magnetic hybrid particles, comprised of a hydrophilic magnetite, synthesized by co-precipitation, in the presence of Pluronic F-127, and a biotinylated N-palmitoyl chitosan matrix. Microscopy images, corroborated with FT-IR spectroscopy results and thermal analysis data confirmed the hybrid structure - multiple magnetite crystallites entrapped in the biofunctionalized polymer matrix, whilst the magnetic assays indicated adequate magnetic properties for biomedical applications. In vitro investigations highlighted that biotin functionalized magnetic hybrid particles are biodegradable and biocompatible, whilst hemocompatibility assessment revealed no significant modifications of blood coagulation times. To conclude, biotin functionalized magnetic hybrid particles exhibited promising assets for future biomedical applications as drug delivery systems or theranostic agents.

The optimization of natural resources of local indonesian materials to synthesize magnetic and magnetic hybrid particles via chemical ablation, co-precipitation, and hydrothermal route process

The magnetic nano-particle synthesized from natural iron sand had been successfully done. Generally, this natural iron sand is a kind of natural waste in Indonesia that has not been optimally used. This research is expected to explain the utilization of Indonesian local natural iron sand as an advanced magnetic material resource. Therefore the reader of this article can develop it for further application. Magnetic particles are a material that is very promising in supporting developments of science and technology. One of them is the development in medical fields. Most previous researchers carried out the magnetic synthesis of particles using chemicals as precursors. In this study, the researchers would like to report how to synthesize magnetic particles using local natural iron sand. The applied method consisted of three steps, namely chemical ablation, co-precipitation, and hydrothermal method. The results of this research showed that Zn-dopped magnetic particles in Quasi-spherical structures become hollow-microsphere morphological structures even though they had not been perfected yet. The Zn-dopped treatment broadens the frequency wave absorptions and magnetism properties. The Zn-dopped Ion had stronger magnetic properties than that of organic factor effects from C-dot that theoretically can decrease the magnetic properties. This article briefly describes the synthesis mechanism of magnetic material from natural iron sand as material resources to substitute highly expensive mainstream chemical material. However, this study still needs to be deeply investigated to produce the optimum scientific application.

Catalytic Activity of Immobilized Chymotrypsin on Hybrid Silica-Magnetic Biocompatible Particles and Its Application in Peptide Synthesis.

In this work, novel silica hybrid magnetic particles with biocompatible surface were designed as a support for enzyme immobilization, and the immobilized chymotrypsin (CT) performance was clarified as a model biocatalyst. CT is used in food technology for drink clarification and protein hydrolysis. The enzyme was directly immobilized onto polydopamine-grafted magnetic silica particles (MNP@SiO2@PDA-CT) via the Schiff base reaction. Immobilized enzyme had broadened for both pH and temperature profiles compared with the native CT. The MNP@SiO2@PDA-CT system also improved in thermostability compared with the native enzyme. The immobilized CT was operated in a continuous enzyme reactor (CER) for the hydrolysis of different proteins (i.e., cytochrome c (Cyt c), human serum albumin (HSA), human immunoglobulin G (HIgG), and lysozyme (Lys)). The peptide synthesis rate was shown to decrease as a function of increasing flow rate. The catalytic activity of the CER remained stable for 6.0 h in a continuous operation period; thus, the presented method may increase applicability in the food technology area. The immobilized CT in the CER showed a good hydrolysis performance for all the tested model proteins. The peptides hydrolyzed from the tested proteins were analyzed with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS). Results show that the MNP@SiO2@PDA-CT system also permits for the applicability in the area of proteomic research.

Synthesis and characterization of Au nanoshells with a magnetic core and betaine derivatives

The article describes preparation, characterization and further modification of hybrid magnetic particles (Au nanoshells with a magnetic core (MPs@silica@Au)) by zwitterionic molecules bearing diazonium functional groups. Such hybrid magnetic particles modified by zwitterionic molecules exhibit the following features:•Responsiveness towards external magnetic field applicable for various enrichment strategies due to magnetic core;•Golden outer layer exhibiting free surface plasmons could be used for grafting of zwitterionic molecules via diazonium functionality;•Zwitterionic interface on such particles provides resistivity towards non-specific protein binding; and at the same time such interface was applied for immobilization of antibodies against prostate specific antigen (PSA) applied for selective enrichment of PSA from serum samples with subsequent electrochemical assays.The approach presented here using hybrid magnetic particles can be easily applied for immobilization of antibodies using a highly robust surface patterning protocols i.e. by formation of a self-assembled monolayer with delivery of functional groups on the outer surface of magnetic particles. Hybrid magnetic particles with immobilized antibodies are applied for highly efficient and quick separation of protein of interest i.e. PSA from complex sample. Finally, hybrid magnetic particles with “fished-out” protein molecules could be incubated with lectins to form a sandwich configuration for glycoprofiling of PSA.

Bio‐Based Hybrid Magnetic Latex Particles Containing Encapsulated γ ‐Fe2O3 by Miniemulsion Copolymerization of Soybean Oil‐Acrylated Methyl Ester and Styrene

AbstractThis work reports the use of acrylated fatty acid methyl ester (AFAME) as a biomonomer for the synthesis of bio‐based hybrid magnetic particles poly(styrene‐co‐AFAME)/γ‐Fe2O3 produced by miniemulsion polymerization. Poly(styrene‐co‐AFAME)/γ‐Fe2O3 can be tailored for use in various fields by varying the content of AFAME. The strategy employed is to encapsulate superparamagnetic iron oxide nanoparticles (SPIONs) as γ‐Fe2O3 into a styrene/AFAME‐based copolymer matrix. Raman spectroscopy is employed to ensure the formation of the SPIONs (γ‐Fe2O3) obtained by a co‐precipitation technique followed by oxidation of Fe3O4. The functionalization of SPIONs with oleic acid (OA) is carried out to increase the SPIONs–monomer affinity. The presence of OA on the surface of γ‐Fe2O3 is certified by identification of main absorption bands by fourier‐transform infrared spectroscopy (FTIR). Thermal analysis (differential thermogravimetry/differential thermo analysis and differential scanning calorimetry) results of poly(styrene‐co‐AFAME)/γ‐Fe2O3 show an increase in AFAME content leading to a lower copolymer glass transition temperature (T g). Dynamic light scattering (DLS) measurements result in poly(styrene‐co‐AFAME)/γ‐Fe2O3 particles with diameter in the range of 100–150 nm. It is also observed by transmission electron microscopy (TEM) and cryo‐TEM techniques that γ‐Fe2O3 particles are successfully encapsulated into the poly(styrene‐co‐AFAME) matrix.

Tuneable thermoresponsive hybrid magnetic nanoparticles: preparation, characterization and drug release characteristics

BACKGROUND Thermo responsive hybrid Ni0.5Zn0.5Fe2O4 magnetic hydrogel particles based on PEG-g-poly(NIPAM-co-AMPS) were synthesized by soap free emulsion polymerization of N-isopropylacrylamide (NIPAM) and 2-acrylamido-2-methylpropane sulphonic acid (AMPS) via free radical mechanism using polyethylene glycol (PEG) as macro-initiator in presence of N,N'-Methylenebisacrylamide (MBA) as cross linking agent. The thermo responsive pure copolymers and hybrid particles were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermo Gravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM) and Dynamic Light Scattering (DLS). Furthermore, the hybrid magnetic particles were used to study the drug release characteristics of theophylline (TPH) as model drug at pH 7.4 and temperature 37°C. RESULTS The sizes of the particles were found to be 121 nm to 245 nm at 50°C and 580 nm to 694 nm at 25°C depending on the amount of AMPS present in the hybrid particles. The volume phase transition temperature (VPTT) of the hybrid particles was tuned above body temperature from 33°C to 41°C. The hybrid magnetic particles with incorporation of AMPS in polymer chains showed high theophylline loading capacity as compare to that of PEG-g-PNIPAM. The entrapment efficiency of theophylline was increasing with increase of AMPS concentration. The releasing capacity of theophylline was decreased with increase in AMPS concentration and observed to have sustained drug release profile without initial burst release. CONCLUSIONS The prepared hybrid particles showed both the temperature sensitive as well as superparamagnetic properties, thus found to be a suitable candidate for applications in targeted drug delivery system.

Optically Active Particles with Tunable Morphology: Prepared by Embedding Graphene Oxide/Fe3O4 in Helical Polyacetylene.

We report a novel and straightforward methodology for constructing hybrid particles with tunable morphology (spherical vs nonspherical) by embedding inorganic components (graphene oxide and/or Fe3O4 nanoparticles) inside chiral helical polyacetylene. Scanning electron microscopic images ascertain the spherical or nonspherical morphology of the particles. The intense circular dichroism effects demonstrate that the hybrid particles (spherical, ellipsoid-like, and cake-like) possess remarkable optical activity. The use of the chiral magnetic hybrid particles in enantioselective crystallization of racemic phenylalanine demonstrates the kind of particles' significant potential applications in chiral technologies and chiral processes. The study not only creates an unprecedented type of chiral hybrid particles, but also provides a versatile strategy for preparing advanced functional hybrid particles with tunable morphology from polymers and even from inorganic and metallic materials.

TGA and magnetization measurements for determination of composition and polymer conversion of magnetic hybrid particles

Magnetic hybrid colloidal particles can be characterized using various techniques and numerous tools leading generally to particles size, size distribution, and electrokinetic properties. However, the chemical composition of these hybrid particles can be estimated using thermal gravimetric analysis (TGA). More interestingly, the combination of this quantitative technique with the magnetization measurement leads not only to chemical composition but also to the overall polymerization conversion and more precisely to the polymerization conversion on the seed particles. In fact, the TGA performed on dried magnetic particles leads to exact organic/inorganic chemical composition. Regarding the magnetization, the amount of magnetic material can be deduced, and consequently, the amount of non‐magnetic material can be also estimated. Thus, TGA and magnetization measurements are considered as complementary techniques for characterization of magnetic hybrid colloidal particles. Copyright © 2015 John Wiley & Sons, Ltd.

Preparation of hydrazine-modified CMC/Fe3O4 hybrid magnetic particles for adsorption of Reactive Blue 21 from water

In this work, chemically modified carboxymethyl cellulose/Fe3O4 particles (MCMC/Fe3O4) with hydrazine were prepared and characterized by scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometer. Batch adsorption experiments were performed to remove Reactive Blue 21 (RB 21) from aqueous solution. Various parameters such as pH, initial dye concentration, adsorbent dosage, contact time, and temperature had been studied. Kinetic studies showed that the dye adsorption process followed a pseudo-second-order kinetic model. The equilibrium data were well described by Langmuir and Dubinin–Radushkevich model. Furthermore, the thermodynamic parameters (positive values of ΔH° and ΔS°, negative values of ΔG°) revealed the feasibility, spontaneity, and endothermic nature of the adsorption.

Preparation and characterization of submicron hybrid magnetic latex particles

Micrometer magnetic hybrid particles are of great interest in biomedical field, and various morphologies have been prepared via encapsulation processes. Regarding submicron, only few processes have been investigated and the most recent one leading to highly magnetic submicron magnetic hybrid particles is based on oil in water magnetic emulsion (MES) transformation. The encapsulation of magnetic iron oxide nanoparticles forming oil in water MES was investigated using different styrene/cross‐linker divinylbenzene volume ratio in the presence of potassium persulfate initiator. The encapsulation performed in this work is basically conducted by using well‐defined oil in water MES as a seed in radical emulsion polymerization. The chemical composition, morphology, iron oxide content, magnetic properties, electrokinetic properties, particle size, and size distribution of the prepared magnetic hybrid particles were examined using various techniques. The desired perfect magnetic core and polymer shell morphology were successfully obtained, and the final magnetic hybrid particles are superparamagnetic in nature and exhibit high iron oxide content (64 wt %). Copyright © 2015 John Wiley & Sons, Ltd.

In vitro MRI of biodegradable hybrid (iron oxide/polycaprolactone) magnetic nanoparticles prepared via modified double emulsion evaporation mechanism

Hybrid magnetic particles are being applied in biomedical field for various aims. One of such aim is use of magnetic particles for diagnostic purposes especially in imaging mechanisms. In vitro magnetic resonance imaging of biodegradable hybrid (iron oxide/polycaprolactone) magnetic nanoparticles is carried out. Hybrid magnetic nanoparticles were prepared by encapsulation of iron oxide nanoparticles (IONPs) in polycaprolactone (PCL) via modified double emulsion evaporation technique. Both the IONPs and hybrid nanoparticles were characterized for their sizes, zeta potential, microscopic, thermogravimetric, and magnetism. Prepared particles were investigated for T1 and T2 weighted enhancement of contrast in vitro in water. A comparison of the prepared particles was done with commercially available Gadolinium for the contrast efficiency in MRI. Results showed the prepared particles exhibited nanosize range, good morphology and superparamagnetic character. The enhancement in the MRI contrast of the prepared particles was observed and found to depend on type of the prepared particles. Comparison of the MRI contrast of the prepared particles with the commercial Gadolinium suggests their usefulness as T2 contrast agent.

Polydopamine assisted preparation of Ti4+‐decorated magnetic particles for selective and rapid adsorption of phosphorylated proteins

AbstractBACKGROUNDPhosphorylated proteins have attracted widespread attention due to their crucial roles in regulating biological processes. Therefore, development of effective methods for identification and detection of phosphorylated proteins is an indispensable step to understand the roles of protein phosphorylation. The aim of this work is to prepare Ti4+‐decorated polydopamine‐grafted hybrid magnetic particles (Ti4+‐PDA@Fe3O4) for highly efficient and selective separation of phosphorylated proteins.RESULTSTi4+‐PDA@Fe3O4 particles were synthesized and characterized. A wealth of hydroxyl groups in PDA enhanced the binding capacity of PDA@Fe3O4 for titanium ions. The selectivity of the particles for phosphorylated proteins relies on the affinity of phosphate groups in phosphorylated proteins to titanium ions on the surface of Ti4+‐PDA@Fe3O4. The adsorption capacity of Ti4+‐PDA@Fe3O4 for β‐casein was 1273.9 mg g‐1. The adsorption conditions and selectivity of Ti4+‐PDA@Fe3O4 for phosphorylated proteins were studied. The feasibility of Ti4+‐PDA@Fe3O4 for separation of phosphorylated proteins from milk was also investigated.CONCLUSIONSTi4+‐PDA@Fe3O4 demonstrated highly effective and selective adsorption property for phosphorylated proteins based on immobilized metal affinity chromatography mechanism. The successful isolation of phosphorylated proteins from milk by Ti4+‐PDA@Fe3O4 demonstrated that the particles will have promising application prospect in selective separation of phosphorylated proteins. © 2015 Society of Chemical Industry

Surface modification of magnetite hybrid particles with carbohydrates and gold nanoparticlesvia “click” chemistry

An efficient method is described to synthesize magnetic particles based on divinylbenzene-co-pentafluorostyrene suitable for further chemical modification and incorporation of active groups, in particular, carbohydrates and gold nanoparticles. The magnetic hybrid particles were prepared via seeded precipitation polymerization consisting of the radical copolymerization of pentafluorostyrene and divinylbenzene in the presence of modified magnetite nanoparticles as seeds. Magnetite nanoparticles were first prepared by a thermal decomposition process followed by their modification with the bioinspired dopamine methacrylamide to incorporate vinyl groups at the particle surface. Then, pentafluorostyrene and divinylbenzene are polymerized through the interface of the magnetite nanoparticles to form the crosslinked polymeric shell. Afterwards, carbohydrate moieties were attached to the particles by the so-called thiol-para-fluorine “click” reaction based on the coupling of acetylated β-D-thioglucopyranose onto pentafluorostyrene via nucleophilic substitution of para-fluorine. Moreover, the fluorinated hybrid particles reacted with 1,2-ethanedithiol in order to introduce thiol groups at the surface that were used further as platforms to stabilize the nucleation and growth of gold nanoparticles. The resultant functional particles with potential interest in recognition processes and catalysis amongst others are responsive to external magnetic fields, making the particles easy to remove from the media.

Preparation and Characterization of Magnetic Functional Hybrid Particles

Hybrid microspheres with a polystyrene core coated with magnetite nanoparticles were prepared by two techniques. Firstly, monodispersed functional polystyrene latex particles were prepared by emulsion polymerization. In a general way chemical groups may be introduced through polymerizable surfactant or functional monomer. Magnetite acidic or alkaline sol was added in, then magnetite nanoparticles were absorbed onto latex particles by electrostatic attraction and core-shell composite particles were formed. Secondly, core-shell composite particles were prepared by miniemulsion polymerization. To modify the tendency of conglomeration of magnetite and increase the amount of magnetic particles onto the composite particles, silane coupling agent MPS was used as surface modification agent for magnetite. A series of different size and coating morphology magnetic hybrid particles were prepared through the adjustment of some experiment parameters. The obtained functional core-shell particles were characterized by FTIR, TEM, etc.

Anisotropic magnetic microparticles from ferrofluid emulsion

A simple synthetic approach for the preparation of anisotropic Janus-like sub-micrometre sized hybrid magnetic particles consisting of inorganic superparamagnetic iron oxide nanoparticles and an organic polymer is demonstrated here. Two-step controlled processes, (a) the swelling of preformed magnetic oil in water ferrofluid droplets with styrene and (b) a seed emulsion polymerization of styrene in the presence of monomer swollen ferrofluid as seed, were accomplished. The swelling of ferrofluid droplets with styrene was investigated by gas chromatography (GC) to point out the partition of styrene in the continuous aqueous phase and in the droplets’ organic phase. A series of seed emulsion polymerizations initiated by AIBN and KPS in different concentrations of styrene was carried out in order to turn the monomer swollen ferrofluid droplets into the magnetic polymer particles having two different phases. This approach allows us to investigate the effect of the seed to monomer ratio and especially the initiator type on the anisotropic morphology of the prepared particles. Most importantly, we demonstrated that the used experimental method enables one to produce magnetic Janus hybrid particles. The independent phase of the anisotropic Janus particle morphology was evidenced by transmission electron microscopy (TEM). The complete characterization of particles was performed using light scattering measurement, thermogravimetric analysis (TGA) and size-exclusion chromatography to explain the properties of such “biphasic” microparticles. An interpretation based on thermodynamics and a proposed tentative polymerization mechanism is also discussed. This procedure can be adopted to produce large quantities of magnetic anisotropic submicron colloidal particles for biotechnological applications.

A novel core-shell structured magnetic organic-inorganic nanohybrid involving drug-intercalated layered double hydroxides coated on a magnesium ferrite core for magnetically controlled drug release

A novel magnetic nanohybrid involving non-steroid anti-inflammatory drug diclofenac (DIC) intercalated Mg–Al layered double hydroxides (LDH) coated on magnesium ferrite particles was assembled via a one step coprecipitation self-assembly method. The XRD, FT-IR and ICP measurements reveal that the magnetic nanohybrid consists of both DIC-LDH nanocrystallite and magnesium ferrite phases. The TEM image shows that the magnetic nanohybrid presents well-defined core-shell structure with diameter in the range of 90–150 nm. Compared to pure DIC-LDH, an obviously smaller dimension and less sharp hexagonal morphology of the coated DIC-LDH nanocrystallites in magnetic hybrids is observed due to a heterogeneous nucleation and crystal growth process with the introduction of the magnetic core. The in vitro drug release rate of the magnetic nanohybrid was thus enhanced owing to the much smaller size of the coated DIC-LDH nanoparticles on the surface of the magnetic core. However, under an external magnetic field of 0.15 Tesla, the drug release rate of the magnetic nanohybrid decreases dramatically owing to the aggregation of the magnetic nanohybrid particles triggered by non-contact magnetic force. The kinetic data reveal that the release of DIC from the magnetic nanohybrid is controlled by particle diffusion, and the release rate is mainly affected by the particle size and the aggregation extent of the hybrid magnetic particles. Additionally, the obtained nanohybrid has a strong magnetization response, implying the possibility of application in magnetic drug targeting.

Magnetorheological Characteristics of Carbonyl Iron Embedded Suspension Polymerized Poly(Methyl Methacrylate) Micro-Bead

Carbonyl iron (CI) based magnetorheological (MR) fluid systems possess some disadvantages including severe sedimentation of the CI particles due to their large density mismatch with the carrier liquid and difficulties in redispersion after caking. In order to not only prevent sedimentation but also enhance re-dispersion of pure magnetic CI particles in MR fluid, hybrid magnetic particles of CI/poly(methyl methacrylate) (PMMA) were prepared via a suspension polymerization method of methyl methacrylate. Since the composite particles of CI-PMMA have a lower density than that of pure CI particles, they are regarded to improve the sedimentation problem of magnetic particles in the MR fluid. Both CI and CI-PMMA particles were dispersed in mineral oil (20 vol%) and their MR characteristics were examined via a rotational rheometer with a magnetic field supplier. Various characterizations of the CI-PMMA particles were performed via SEM and FT-IR. Shear stress as a function of shear rate of the MR fluid was investigated under magnetic field strengths exhibiting typical MR performance.

PREPARATION AND MAGNETORHEOLOGICAL CHARACTERIZATION OF CI/PVB CORE/SHELL PARTICLE SUSPENDED MR FLUIDS

Hybrid magnetic particles of carbonyl iron ( CI ) /poly(vinyl butyral) ( PVB ) with core/shell microstructure ( CI - PVB ) were prepared in order to enhance the dispersion stability of the magnetorheological (MR) fluids. Since the composite particles of CI - PVB have a lower density than that of the pristine CI particles, they are regarded to improve the sedimentation problem of magnetic particles in the MR fluid when the particles are dispersed in a mineral oil and to make easy redispersion after caking. The PVB coating layers were found to play an important role in the steric repulsion between the relatively large CI particles. Morphology and composition of the CI - PVB particles were observed via SEM and TGA, respectively. Flow properties of both CI and CI - PVB based MR fluids were examined via a rotational rheometer in parallel plate geometry equipped with a magnetic field supplier.

Encapsulation of Carbonyl Iron Particles with Poly(Vinyl Butyral) and their Magnetorheology

To enhance dispersion stability of magnetorheological (MR) fluids, hybrid magnetic particles of carbonyl iron (CI)/ poly(vinyl butyral) (PVB) with core/shell microstrcutre (CI-PVB) were prepared, since pure magnetic CI based MR fluid systems show severe sedimentation of the CI particles due to the large density mismatch with the carrier liquid and difficulties in redispersion after caking. The composite particles of CI-PVB have a lower density than that of the pure CI particles, while exhibiting almost original magnetic property of the CI. Both CI and CI-PVB particles were dispersed in mineral oil (20 vol%) and their MR characteristics were examined via a rotational rheometer with a magnetic field supplier. Various characterizations of the CI-PVB particles were performed via SEM, TEM and FT-IR. Both yield stress and flow curve of shear stress as a function of shear rate of the MR fluids were investigated under applied magnetic field strengths.