Hydrophilic Magnetic Nanoparticles Research Articles

Droplet manipulation in liquid flow using of magnetic micromotors for drug delivery and microfluidic systems

The task of droplet manipulation is of great practical importance in such areas as biochemistry, drug delivery and microfluidic systems. Here we demonstrate a method for controlling the movement of droplets in an oil-in-water emulsion flow using magnetic nanoparticles (MNPs). A distinctive feature of this method is that the MNPs are not dispersed within droplets but in the continuous phase of the emulsion. Due to this, after the droplet manipulation procedure is completed, the MNPs can be easily removed from the emulsion without destroying the droplets. This method represents an innovative alternative to the previously known methods. The MNPs can be used to change the speed and direction of droplet movement in a liquid flow. If the magnetic field gradient is directed against the liquid flow, and the flow velocity is less than a certain critical value, then with help of a magnetic field it is possible to move droplets against the liquid flow. The ability to control the movement of droplets in a flow largely depends on the surface wettability of the MNPs. Hydrophobic MNPs are adsorbed on the surface of droplets and move with them in a magnetic field. If the magnetic field gradient is directed along the liquid flow, this leads to an increase in the droplet speed. In the case of using hydrophilic MNPs, the influence of the magnetic field on the droplet speed in the flow turns out to be ambiguous. These results can provide a basis for the development of magnetic droplet-based drug delivery systems.

Palladium supported on hydrophilic magnetic nanoparticles as a new efficient catalyst in aqueous media✰

Designing efficient hydrophilic catalysts for applying in aqueous media is still a great sustainable processes challenge. In this research, glycerol as a nontoxic and biodegradable chemical was used for preparation of water dispersible magnetic nanoparticles which was applied for stabilization of Pd NPs. Resulting composite (Fe3O4@SiO2-T-G@Pd) was characterized using multiple techniques including FTIR, SEM mapping, TEM, XRD, VSM, and TGA. Hydrophilic property of the Fe3O4@SiO2-T-G@Pd was proved by experiments. This magnetic palladium catalyst showed high catalytic performance in the conversion of nitro compounds to corresponding amines as well as in CC coupling reactions in aqueous media with high efficiency and selectivity. Using this catalyst and NaBH4 as reducing agent, structurally different nitroarenes were reduced to corresponding amines with very good to excellent yields in aqueous media at room temperature. Furthermore, typical Suzuki-Miyaura coupling reaction of 4-bromoanisole with phenylboronic acid was proceeded very well in aqueous media at 60 °C. The magnetically water dispersible catalyst was recycled and reused several cycles in the reduction of nitrobenzene without significant loss in its activity and stability such as confirmed TEM, SEM and XPS analyses.

Amphiphilic axially modified cationic indium-porphyrins linked to hydrophilic magnetic nanoparticles for photodynamic antimicrobial chemotherapy against gram-negative strain; Escherichia coli

In this study, we report on the synthesis, characterization, and application of indium porphyrins linked to silver core-shell magnetic nanoparticles for in vitro photodynamic antimicrobial chemotherapy (PACT) against gram-negative strain, E. coli. This work compares the photophysicochemical and PACT activities of InCl 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridinium)-triiodide porphyrin (1), InCl 5-p-carboxyphenyl-10-15-20-(tris-4-hexylpyridinium)-triiodide porphyrin (2), In (para-aminophenyl) 5,10,15,20-tetrakis(4-methylpyridinium)-tetraiodide porphyrin (3), and In (para-aminophenyl) 5,10,15,20-tetrakis(4-hexylpyridinium)-tetraiodide porphyrin (4). The comparisons were based on the structure and number of charges. Hydrophilic and hydrophobic characters of the amphiphilic porphyrins were studied by comparing the effect of the different alkyl halides (iodomethane and iodohexane) quaternizing agents. The porphyrin complexes were further linked to magnetic nanoparticles to facilitate antimicrobial synergy and recovery of the complexes after use. High Log reduction values ranging from 7.19 to 9.58 were obtained for the quaternized complexes.

Poly(N-acryloyl-glucosamine-co-methylenebisacrylamide)-based hydrophilic magnetic nanoparticles for the extraction of aminoglycosides in meat samples

Poly(N-acryloyl-glucosamine-co-methylenebisacrylamide) (poly(AGA-co-MBA))-modified Fe3O4 nanoparticles were prepared via simple aqueous surface polymerization. The resultant Fe3O4@poly(AGA-co-MBA) nanoparticles were used as hydrophilic magnetic solid phase extraction sorbents. Ten aminoglycosides were selected as model analytes to evaluate the extraction performance and mechanism of the sorbents. The prepared magnetic nanoparticles were characterized by Fourier transformed infrared spectroscopy, elemental analysis, a vibrating sample magnetometer, and so on. The sorbents exhibited efficient extraction towards model analytes in hydrophilic interaction chromatography. Only 10.0 mg of sorbent was needed to adsorb analytes from 10.0 mL of a sample solution within a short time (5.0 min). Under optimized conditions, Fe3O4@poly(AGA-co-MBA) nanoparticles were applied in the sample preparation for the analysis of 10 aminoglycosides in meat samples by high-performance liquid chromatography-tandem mass spectrometry. The limits of detection (LODs) for the 10 aminoglycosides were in the range of 0.6–23.6 µg kg−1. Satisfactory recoveries of spiked meat samples from 84.6–98.3% with acceptable relative standard deviations from 3.1% to 7.8% were achieved. Compared to other reported methods for the analysis of aminoglycosides, the present work had comparable or higher sensitivities with a simple extraction procedure. The proposed hydrophilic interaction extraction sorbents are promising as powerful alternatives for extracting and enriching aminoglycosides in animal-derived food samples.

Carbon-Based Magnetic Nanocarrier for Controlled Drug Release: A Green Synthesis Approach

In this study, hydrophilic magnetic nanoparticles were synthesized by green routes using a methanolic extract of Rubus ulmifolius Schott flowers. The prepared magnetic nanoparticles were coated with carbon-based shell for drug delivery application. The nanocomposites were further chemically functionalized with nitric acid and, sequentially, with Pluronic® F68 (CMNPs-plur) to enhance their colloidal stability. The resulting material was dispersed in phosphate buffer solution at pH 7.4 to study the Doxorubicin loading. After shaking for 48 h, 99.13% of the drug was loaded by the nanocomposites. Subsequently, the drug release was studied in different working phosphate buffer solutions (i.e., PB pH 4.5, pH 6.0 and pH 7.4) to determine the efficiency of the synthesized material for drug delivery as pH-dependent drug nanocarrier. The results have shown a drug release quantity 18% higher in mimicking tumor environment than in the physiological one. Therefore, this study demonstrates the ability of CMNPs-plur to release a drug with pH dependence, which could be used in the future for the treatment of cancer "in situ" by means of controlled drug release.

Can Pulsed Electromagnetic Fields Trigger On-Demand Drug Release from High-Tm Magnetoliposomes?

Recently, magnetic nanoparticles (MNPs) have been used to trigger drug release from magnetoliposomes through a magneto-nanomechanical approach, where the mechanical actuation of the MNPs is used to enhance the membrane permeability. This result can be effectively achieved with low intensity non-thermal alternating magnetic field (AMF), which, however, found rare clinic application. Therefore, a different modality of generating non-thermal magnetic fields has now been investigated. Specifically, the ability of the intermittent signals generated by non-thermal pulsed electromagnetic fields (PEMFS) were used to verify if, once applied to high-transition temperature magnetoliposomes (high-Tm MLs), they could be able to efficiently trigger the release of a hydrophilic model drug. To this end, hydrophilic MNPs were combined with hydrogenated soybean phosphatidylcholine and cholesterol to design high-Tm MLs. The release of a dye was evaluated under the effect of PEMFs for different times. The MNPs motions produced by PEMF could effectively increase the bilayer permeability, without affecting the liposomes integrity and resulted in nearly 20% of release after 3 h exposure. Therefore, the current contribution provides an exciting proof-of-concept for the ability of PEMFS to trigger drug release, considering that PEMFS find already application in therapy due to their anti-inflammatory effects.

Maltose-Functionalized Hydrophilic Magnetic Nanoparticles with Polymer Brushes for Highly Selective Enrichment of N-Linked Glycopeptides.

Efficient enrichment glycoproteins/glycopeptides from complex biological solutions are very important in the biomedical sciences, in particular biomarker research. In this work, the high hydrophilic polyethylenimine conjugated polymaltose polymer brushes functionalized magnetic Fe3O4 nanoparticles (NPs) denoted as Fe3O4–PEI–pMaltose were designed and synthesized via a simple two-step modification. The obtained superhydrophilic Fe3O4–PEI–pMaltose NPs displayed outstanding advantages in the enrichment of N-linked glycopeptides, including high selectivity (1:100, mass ratios of HRP and bovine serum albumin (BSA) digest), low detection limit (10 fmol), large binding capacity (200 mg/g), and high enrichment recovery (above 85%). The above-mentioned excellent performance of novel Fe3O4–PEI–pMaltose NPs was attributed to graft of maltose polymer brushes and efficient assembly strategy. Moreover, Fe3O4–PEI–pMaltose NPs were further utilized to selectively enrich glycopeptides from human renal mesangial cell (HRMC, 200 μg) tryptic digest, and 449 N-linked glycopeptides, representing 323 different glycoproteins and 476 glycosylation sites, were identified. It was expected that the as-synthesized Fe3O4–PEI–pMaltose NPs, possessing excellent performance (high binding capacity, good selectivity, low detection limit, high enrichment recovery, and easy magnetic separation) coupled to a facile preparation procedure, have a huge potential in N-glycosylation proteome analysis of complex biological samples.

Preparation of highly hydrophilic magnetic nanoparticles with anion-exchange ability and their application for the extraction of non-steroidal anti-inflammatory drugs in environmental samples.

Diallyldimethylammonium chloride modified magnetic nanoparticles were synthesized by the "thiol-ene" click chemistry reaction. Diallyldimethylammonium chloride rendered the material plenty of quaternary ammonium groups, and thus the excellent aqueous dispersibility and anion-exchange capability. The novel material was then used as the magnetic solid-phase extraction sorbent to extract eight non-steroidal anti-inflammatory drugs from water samples. Combined with high-performance liquid chromatography and ultraviolet detection, under the optimal conditions, the developed method exhibited wide linearity ranges (1-1000, 2-1000, and 5-1000ng/mL) with recoveries of 88.0-108.6% and low limits of detection (0.3-1.5ng/mL). Acceptable precision was obtained with satisfactory intra- and inter-day relative standard deviations of 0.4-4.4% (n=3) and 1.1-5.5% (n=3), respectively. Batch-to-batch reproducibility was acceptable with relative standard deviations<9.7%. The hydrophilic magnetic nanoparticle featured with quaternary ammonium groups showed high analytical potential for acidic analytes in environmental water samples.

Attachment of enzymes to hydrophilic magnetic nanoparticles through DNA-directed immobilization with enhanced stability and catalytic activity

An efficient enzyme immobilization strategy based on DNA directed immobilization on hydrophilic polydopamine (PDA) modified magnetic nanoparticles was developed in this study.

Characterization and Chemical Stability of Hydrophilic and Hydrophobic Magnetic Nanoparticles

Magnetic nanoparticles can improve the efficiency of phase separation time in multi-stage operations when a magnetic field is present. As such operations involve contact with aqueous and/or organic solutions, hydrophilic magnetic nanoparticles synthesized through the co-precipitation method were functionalized with oleic acid to attain hydrophobic magnetic nanoparticles. Both nanoparticles were characterized morphologically, chemically and magnetically. The results revealed that the particles (size ≈ 10 nm) consisted of an iron oxide mixture of magnetite and maghemite. The functionalization with oleic acid was effective in converting them into hydrophobic nanoparticles. Both particles were ferro/ferrimagnetic and the presence of oleic acid did not interfere significantly in the saturation magnetization value. The chemical stability of both nanoparticles were also evaluated, as an attempt of simulating broad industrial conditions to which the nanoparticles may be subjected; the hydrophilic nanoparticles were resistant at pH ≥ 4, while the hydrophobic nanoparticles were stable at pH ≥ 3.

Dendrimer-assisted hydrophilic magnetic nanoparticles as sensitive substrates for rapid recognition and enhanced isolation of target tumor cells

Capture and detection of targeted tumor cells provide a significant meaning in the early diagnosis and therapy of cancer. Nowadays, the development of advanced nanomaterials for cell capture is outstanding, however there still remain great challenges and extensible space. Herein we report a novel and cushy method to synthesize the epidermal growth factor receptor antibody (anti-EGFR) functionalized dendrimer-assisted hydrophilic magnetic nanoparticles as sensitive substrates, which possess excellent capability of rapid targeting and highly efficient capturing of tumor cells. The introduction of dendrimers immensely improves the hydrophilicity and modification sites of substrates, which not only accelerates the procedure of cell capture, but also improves the amount of antibodies conjugated with the magnetic nanoparticles (MNPs). Thus, the newly synthesized substrates not only cut down the recognition time but also realize highly selective capture of target tumor cells. Moreover, the characteristics of MNPs lead to the rapid contact between substrates and cells and quick separation from the reaction solution. As a result, the functional MNPs can capture 86%±5% of tumor cells and isolate rare number of tumor cells from spiked whole blood samples in only 15min without the damage of cell viability. These results suggest that our method is reliable and has great potential in the application of cell isolation.

Thiol-ene click synthesis of L-Cysteine-bonded zwitterionic hydrophilic magnetic nanoparticles for selective and efficient enrichment of glycopeptides

Efficient and specific enrichment of low-abundant glycopeptides from complex biological samples is essential to glycoproteomics analysis. Herein, novel magnetic zwitterionic hydrophilic nanoparticles based on thiol-ene click chemistry were synthesized. The functionalized magnetic nanoparticles exhibited superior performance in glycopeptide enrichment of HRP tryptic digest, demonstrating low detection limit (0.04ng/μL), high selectivity (a mixture of HRP and BSA at the mass ratio of 1:50) and reproducibility (5 repeating cycles). In addition, the material was successfully applied to glycopeptide enrichment from human serum. The outstanding results indicate the potential of the method in the development of glycoproteomics analysis in real biological samples.

Lanthanide-Functionalized Hydrophilic Magnetic Hybrid Nanoparticles: Assembly, Magnetic Behaviour, and Photophysical Properties.

The lanthanide-functionalized multifunctional hybrid nanoparticles combining the superparamagnetic core and the luminescent europium complex were successfully designed and assembled via layer-by-layer strategy in this work. It is noted that the hybrid nanoparticles were modified by a hydrophilic polymer polyethyleneimine (PEI) through hydrogen bonding which bestowed excellent hydrophilicity and biocompatibility on this material. A bright-red luminescence was observed by fluorescence microscopy, revealing that these magnetic-luminescent nanoparticles were both colloidally and chemically stable in PBS solution. Therefore, the nanocomposite with magnetic resonance response and fluorescence probe property is considered to be of great potential in multi-modal bioimaging and diagnostic applications.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-016-1497-3) contains supplementary material, which is available to authorized users.

Hydrophilic Magnetite Nanoparticles Enhance Anticancer Activity of Anthracyclines In Vitro

A novel method for enhancing the anticancer activity of anthracyclines in vitro was proposed by using hydrophilic magnetic nanoparticles. Citric acid-coated magnetite nanoparticles Fe3O4 (nano-Fe3O4-CA) interacted with anthracyclines by electrostatic and hydrophobic forces, resulting in the formation of aggregates (nano-Fe3O4-CA-drug). The aggregate was studied by resonance light scattering and fluorescence spectroscopy. The results indicated that in comparison with anthracyclines, the nano-Fe3O4-CA-drug showed high activity towards incorporation in the DNA chain. Furthermore, the cytotoxicity of nano-Fe3O4-CA-drug was investigated by cytotoxicity experiment and cell morphology study. The results confirmed that the nano-Fe3O4-CA-drug could inhibit the growth of cells more effectively than the drug alone. In conclusion, usage of nano-Fe3O4-CA affords reduction of the dosage of anthracyclines in vitro.

Use of synthesized hydrophilic magnetic nanoparticles (HMNPs) in forward osmosis for water reuse

Forward osmosis (FO) is attracting worldwide attention as an emerging technology in the fields of power generation, water reuse, desalination, pharmaceuticals and food processing. Still, the critical challenge of finding a suitable draw solute for FO persists. Therefore the current research focuses on synthesizing hydrophilic magnetic nanoparticles (HMNPs) and systematically investigating their potential as draw solutes. HMNPs were synthesized using functional groups polyethylene glycol (PEG 400) and polyacrylic acid (PAA). These functional groups under different ratios with a metal precursor react by one-pot polyol and thermal decomposition methods respectively to give different diameter HMNPs. In addition the effect of different sizes of synthesized HMNPs was investigated for their recovery under an external magnetic field and reusability in FO performance. The physical properties and chemical compositions of the resultant MNPs are fully characterized. Transmission electron microscopy (TEM) analyses show the characteristics as spherical morphology with a narrow size distribution, and a mean size from 9 to 32.5 nm for PEG and 8 to 30 nm for PAA coated HMNPs depending on the ratio of the functional group and metal precursor. The PEG and PAA layer on the MNPs is confirmed by Fourier transform infrared (FTIR) analysis, and thermogravimetric analysis demonstrates a hydrophilic surface composition. The PEG and PAA coated HMNPs generate high osmotic pressures and exhibit good dispersibility in aqueous solutions. Water fluxes of &amp;gt;13 L m−2 h−1 are achieved across Hydration Technologies Inc. flat sheet membranes at a concentration of 0.05 M of HMNPs using deionized water as the feed solution. The HMNPs can be easily recaptured from draw solutions by applying an external magnetic field and recycling them back as draw solute in the FO process. The MNPs remain active after nine runs of recycling but with a total water flux decrease of 5% in PEG and 3% with each successive recycling due to slight aggregation, and reduced surface to volume ratio is observed. Results of the present study have demonstrated that PEG and PAA coated HMNPs can viewed as promising and potential draw solutes in the FO process.

SiO2 versus chelating agent@ iron oxide nanoparticles: interactions effect in nanoparticles assemblies at low magnetic field

Hydrophilic magnetic nanoparticles present many interest for various medical applications due to their unique properties: immunoassays, imaging and hyperthermia. With regards to their applicability in the biomedical field, colloidal stability is a key parameter related to nanoparticle surface functionalization. In this paper, we report the water transfer of hydrophobic oleic acid coated iron oxide nanoparticles comparing two methodologies to obtain water dispersible iron oxide nanoparticles: exchange ligands with small strong chelating agent (caffeic acid) and SiO2 shell passivation. Both strategies are leading to stable aqueous ferrofluid but differing by their interactions. The non linear magnetic behavior at high and low magnetic field and second derivative signature of water dispersed superparamagnetic Fe304 nanoparticles samples are studied using conventional SQUID equipment and miniaturized detector MIAplex® device. We demonstrated those samples differing only by their interparticle interactions present different magnetic behavior at very low magnetic field whereas at high magnetic field both samples are very similar.

Click synthesis of glucose-functionalized hydrophilic magnetic mesoporous nanoparticles for highly selective enrichment of glycopeptides and glycans

Selective enrichment of glycopeptides from complex biological samples is essential for MS-based glycoproteomics, but challenges still remain. In this work, glucose-functionalized magnetic mesoporous nanoparticles (MMNs), which hold the attractive features of well-defined core/shell structure, high specific surface area (324m2/g), narrow pore size distribution (2.2nm) and high magnetic responsivity (69.1emug−1), were synthesized via click chemistry and applied to enrich glycopeptides and glycans. Taking advantages of the size-exclusive effect of mesopore against proteins and the hydrophilic interaction between glycans and glucose, the hydrophilic MMNs possessed high selectivity for glycopeptides at the digested mixtures of horseradish peroxidase (HRP), myoglobin and β-casein at molar ratio of 1:1:10, large enrichment capacity (as high as 250mg/g), high sensitivity (50fmol), excellent speed (5min for enrichment) and high recovery of glycopeptides (as high as 94.6%). Additionally, the MMNs exhibited excellent performance in enrichment of N-linked glycans from the digested human serum that are made up of peptides, large proteins and other compounds. These outstanding features will give the hydrophilic MMNs high benefit for MS analysis of low-abundance glycopeptides/glycans.

The solvothermal synthesis of magnetic iron oxide nanocrystals and the preparation of hybrid poly(l-lactide)–polyethyleneimine magnetic particles

We report a simple and green procedure for the preparation of magnetic iron oxide nanocrystals via solvothermal synthesis. The nanocrystal synthesis was carried out under mild conditions in the water–ethanol–oleic acid solvent system with the use of the oleate anion as a surface modifier of nanocrystals and glucose as a reducing agent. Specific conditions for homogenous precipitation achieved in such a reaction system lead to the formation of uniform high-quality nanocrystals down to 5nm in diameter. The obtained hydrophobic nanocrystals can easily be converted to hydrophilic magnetic nanoparticles by being immobilized in a poly(l-lactide)–polyethyleneimine polymeric matrix. These hybrid nano-constructs may find various biomedical applications, such as magnetic separation, gene transfection and/or magnetic resonance imaging.

Synthesis of highly hydrophilic magnetic nanoparticles of Fe3O4 for potential use in biologic systems

Nanoparticles of Fe3O4 with enhanced hydrophilic properties were synthesized using a co-precipitation approach of Fe2+ and Fe3+ ions in a basified aqueous solution followed by a surface treatment. Two surfacing strategies, using a two-step approach, were used to coat synthesized nanoparticles with silanes of different functional groups for further treatment with ethylenediamine: (i) Michael addition and (ii) nucleophilic addition. Wide-angle X-ray diffraction (WAXD) revealed the pristine nanoparticles with 6.3nm of diameter. Before the surface treatment with ethylenediamine, stirred suspensions of silanized nanoparticles in water showed segregation after a few minutes in repose. On the other hand, the suspensions of nanoparticles silanized and functionalized with ethylenediamine became homogenous and translucent in water. The advantage of the developed nanoparticles is that (because of their high hydrophilicity) they could interact with biological species such as enzymes, proteins, aminoacids and DNA.

One-pot solvothermal method to prepare functionalized Fe3O4 nanoparticles for bioseparation

Abstract