Modified Iron Oxide Magnetic Nanoparticles Research Articles

Extraction and electrochemical detection for quantification of trace-level DNA.

A novel strategy was developed to extract, detect, and quantify trace-level DNA. For the extraction step, a composite of methylene blue (MB), poly(acrylic acid) (PAA), and modified iron oxide magnetic nanoparticles (IOMNPs) (PAA/IOMNPs) was used to adsorb DNA from the sample. MB-PAA/IOMNPs with adsorbed DNA were then separated from the solution with an external magnet and MB-DNA was eluted from PAA/IOMNPs with acetic acid. In the detection step, MB-DNA was adsorbed on the surface of 3-aminopropyltriethoxysilane (APTES)-modified glassy carbon electrode via electrostatic force. DNA was quantified by measuring the oxidation peak of MB at a potential -0.13V vs. Ag/AgCl using differential pulse voltammetry. Under the optimal experimental conditions, the DNA sensor showed linear ranges from 0.001 to 0.005pgμL-1, 0.005 to 0.070pgμL-1, and 0.070 to 0.400pgμL-1 and a limit of detection of 0.87fgμL-1. The proposed sensor detected trace DNA in real samples with recoveries that ranged from 80.4 to 90.4%.

New Insight about Biocompatibility and Biodegradability of Iron Oxide Magnetic Nanoparticles: Stereological and In Vivo MRI Monitor

Iron oxide magnetic nanoparticles (IONPs) have attracted enormous attention because of their extensive medicinal and industrial applicability. PEGylated L-arginine modified iron oxide magnetic nanoparticles (PEG-Arg@IONPs) were synthesized and functioned in the present research as MRI contrast agents considered in vivo BALB/c model. The Synthesized PEG-Arg@IONPs were tracked in certain time intervals by MRI. The intensity of MR imaging of kidneys increased after administration of PEG-Arg@IONPs, which could confirm the emission of these nanoparticles by kidneys shortly after administration. Although PEG-Arg@IONPs were uptake by liver within 2 hours after injection, whereas, the signal change intensity of spleen, heart and kidneys confirmed that PEG-Arg@IONPs existed in other organs. The results illustrated that IONPs coated with PEGylated natural amino acid thin layers had a long circulation time and could be served as T2 contrast agents for diagnosis purpose. Notably, to the best of our knowledge, it was the first time the biocompatibility and biodegradability of IONPs was studied and evaluated by stereological and MRI technique.

Magnetic Sagnac Interference Measurements of Agglomeration and Deagglomeration of Magnetic Nanoparticles

Abstract Magnetic field induced Sagnac interference was observed for the COOH modified iron oxide magnetic nanoparticles (MNPs) dispersed in water. The effect of cationic surfactants showing agglomeration and deagglomeration of the MNPs was clearly detected by the phase shift due to the magnetic orientation of MNPs. The observed phase shifts were discussed by using Langevin parameters.

Preparation, characterization, and evaluation of amino acid modified magnetic nanoparticles: drug delivery and MRI contrast agent applications

This study is a report about the synthesis iron oxide magnetic nanoparticles (IONPs) which modified with positive and negative charged amino acids (AAs). l-Arginine (Arg) and l-aspartic acid (Asp) which have of guanidinium and carboxylic acid groups, respectively, were selected for this study. After loading chrysin in amino acids modified iron oxide magnetic nanoparticles (F@AAs@Chrysin NPs), it was characterized by XRD, TGA, FTIR, VSM, and TEM techniques. Finally, MTT assays on HFF-2 and HEK-293 cell lines were performed for determination of biocompatibility of AA coated IONPs. The results show that, the ζ-potential and average size of F@Arg@chrysin NPs and F@Asp@chrysin NPs were to −3.87, −2.12 mV, 18.75 ± 2.40 (mean ± SD (n = 50)) nm, and 19.86 ± 2.22 (mean ± SD (n = 48)) nm, respectively. Also, the results indicated that these F@AAs@Chrysin NPs were appropriate for delivery of chrysin. Furthermore, the phantom MRI studies showed the IONPs can be used as contrast agent for the revealing of tumor.

Theranostic nanoparticles based on magnetic nanoparticles: design, preparation, characterization, and evaluation as novel anticancer drug carrier and MRI contrast agent

In this work, we reported the synthesis of curcumin (CUR)-loaded hydrophilic and hydrophobic natural amino acids (AAs)-modified iron oxide magnetic nanoparticles (IONPs). Two types of AAs, l-lysine (Lys) and l-phenylalanine (PhA), were selected to study their effects on loading capacity, release profile of CUR, biocompatibility, and anticancer activity. CUR-loaded AAs-modified IONPs (F@AAs@CUR NPs) were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM) techniques. Next, the various kinetic equations were fitted to the release data of CUR from F@Lys@CUR NPs and F@PhA@CUR NPs. Additionally, hemolysis test and MTT assays on HFF-2 and HEK-293 cell lines were performed for determination of biocompatibility of AAs-coated IONPs. Finally, the anticancer activity of F@AAs@CUR NPs examined on MCF-7 breast cancer cell line. The results indicate that these nanocarriers are nontoxic and biocompatible and also F@AAs@CUR NPs are suitable carriers for delivery of curcumin and even other hydrophobic drugs. Also, the MRI training established the effectiveness of IONPs as contrast agent for the revealing of tumor as evidenced from the phantom images as well as higher T2 relaxivity.

Reusable magnetic nanobiocatalyst for synthesis of silver and gold nanoparticles

In the present work, we describe a simple procedure for the biosynthesis of nanosilver and gold by the reduction of silver nitrate and auric chloride respectively using a nanobiocatalyst. The nanobiocatalyst was prepared by covalent coupling of alpha amylase on (3-aminopropyl)triethoxysilane (APTES) modified iron oxide magnetic nanoparticles. The nanobiocatalyst retains 77% of its activity as compared to free alpha amylase. The nanobiocatalyst can be used up to three consecutive cycles for the synthesis of nano silver and gold. The biosynthesized nanoparticles after each cycle were characterized by UV–vis spectrophotometer, Dynamic Light Spectroscopy (DLS), Transmission Electron Microscope (TEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Silver and gold nanoparticles of same morphology and dimensions were formed in each cycle. The procedure for synthesis of nanoparticles using an immobilized enzyme is eco-friendly and can be used repeatedly.

Efficient removal of deltamethrin from polluted aquatic media by modified iron oxide magnetic nanoparticles

Efficient removal of deltamethrin from polluted aquatic media by modified iron oxide magnetic nanoparticles

Improvement of the stability and activity of immobilized glucose oxidase on modified iron oxide magnetic nanoparticles

Immobilized proteins and enzymes are widely investigated in the medical field as well as the food and environmental fields. In this study, glucose oxidase (GOX) was covalently immobilized on the surface of modified iron oxide magnetic nanoparticles (MIMNs) to produce a bioconjugate complex. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to the size, shape and structure characterization of the MIMNs. Binding of GOX to these MIMNs was confirmed by using FT-IR spectroscopy. The stability of the immobilized and free enzyme at different temperature and pH values was investigated by measuring the enzymatic activity. These studies reveal that the enzyme's stability is enhanced by immobilization. Further experiments showed that the storage stability of the enzyme is improved upon binding to the MIMNs. The results of kinetic measurements suggest that the effect of the immobilization process on substrate and product diffusion is small. Such bioconjugates can be considered as a catalytic nanodevice for accelerating the glucose oxidation reaction for biotechnological purposes.

Surface modified magnetic nanoparticles as efficient and green sorbents: Synthesis, characterization, and application for the removal of anionic dye

The object of this study was to evaluate the removal efficiency of sunset yellow (SY) anionic dye from aqueous solutions by using new surface modified iron oxide magnetic nanoparticles (MNPs). Pure Fe3O4 MNPs were synthesized and then functionalized by aminopropyltriethoxysilane (APTES), through a chemical precipitation method. Characterization of the prepared MNP adsorbents was performed by furrier transform infrared (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM). According to XRD and TEM results, average size of the magnetic Fe3O4/APTES NPs was estimated to be around 12nm. The prepared magnetic adsorbent can be well dispersed in the water and easily separated magnetically from the medium after loaded with adsorbate. In the adsorption process, the effect of main experimental parameters such as pH of dye solution, initial concentration of SY dye, reaction time, and amount of MNP adsorbent on the removal of SY were studied and optimized. The small amount of this adsorbent (10mg) is applicable for the removal of high concentrations of SY dye in reasonable time (17min), at pH 3.1. Additionally, the adsorption studies show that the Langmuir model is a suitable model to explain the experimental data with high correlation coefficient.

Synthesis and characterization of magnetic polyHIPEs with humic acid surface modified magnetic iron oxide nanoparticles

Magnetic macroporous polymer monoliths have been prepared using styrene/divinylbenzene (S/DVB) high internal phase emulsions (HIPEs) as templates. Humic acid surface modified iron oxide magnetic nanoparticles (Fe3O4@HA) have been used to prepare magnetic emulsion templates. The effect of magnetic particle concentration has been investigated by changing the ratio of Fe3O4@HA nanoparticles in the continuous phase. Highly macroporous polymers with magnetic response were obtained by the removal of the internal phase after the curing of emulsions at 80°C. Fe3O4@HA particles were characterized by XRD and FTIR. The porosity, pore morphology and magnetic properties of the macroporous polymers were characterized as a function of the Fe3O4@HA concentration by scanning electron microscopy (SEM), Brunauer–Emmet–Teller (BET) molecular adsorption method and vibrating sample magnetometry (VSM), respectively. BET and VSM measurements demonstrated that the specific surface area and the saturation magnetization of the polymer monoliths were changed according to the Fe3O4@HA concentration between 8.77–35.08m2g−1 and 0.63–11.79emug−1, respectively. Resulting magnetic monoliths were tested on the adsorption of Hg(II) and atomic absorption spectroscopy (AAS) was used to calculate the adsorption capacities. The maximum adsorption capacity of the magnetic monoliths was calculated to be 20.44mmolg−1 at pH 4.

Prussian blue modified iron oxide magnetic nanoparticles and their high peroxidase-like activity

Prussian blue (PB) modified γ-Fe2O3 magnetic nanoparticles (MNPs) featuring varying PB proportions were synthesized and characterized by TEM, FTIR, UV-vis, EDS, XRD and XPS. The magnetic properties and peroxidase-like catalytic activity of the synthesized nanoparticles were investigated. With increasing PB content, the magnetism could still maintain a high level. Peroxidase-like activity was enhanced as the PB proportion increased. Catalysis was found to follow Michaelis–Menten kinetics. The calculated kinetic parameters exhibited strong affinity with substrates and high catalytic activity, which are three orders of magnitudes larger than that for magnetite nanoparticles of similar size. Based on the high activity, an enzyme immunoassay model was established: staphylococcal protein A (SPA) was conjugated onto the surface of the nanoparticles to construct a new nanoprobe which was employed to detect IgG immobilized to 96-well plates. The results presented a linear absorbance enhancement with concentration of IgG, suggesting that PBMNPs serve as an inexpensive horseradish peroxidase (HRP) mimic enzyme with potential applications in bio-detection.

Fast removal and recovery of amaranth by modified iron oxide magnetic nanoparticles

The adsorption and removal of amaranth (AM) from an aqueous solution by iron oxide nanoparticles (IONPs) coated with cetyltrimethylammonium bromide (CTAB) as adsorbent was reported. The novel magnetic separation was quite efficient for the adsorption and desorption of AM. In an aqueous solution of AM at 25 °C, the adsorption data could be fitted by the Langmuir equation with a maximum adsorption amount of 1.05 mg mg −1 and a Langmuir adsorption equilibrium constant of 0.90 L mg −1. The effect of temperature, pH of aqueous medium, electrolyte concentration, composition of desorbent solvent and interfering ions on the recovery process were also investigated. Methanol was used for desorption of adsorbed AM. Due to the absence of internal diffusion resistance both adsorption and desorption of AM were fast and could be completed within 5 min. The results indicated that the CTAB-coated IONPs could be employed in the removal of the anionic dye from wastewater. The AM was removed successfully in spiked samples of Karoon River water.