Concentrations Of Iron Oxide Nanoparticles Research Articles

Uptake and clearance analysis of Technetium99m labelled iron oxide nanoparticles in a rabbit brain.

Nanoparticles as solid colloidal particles are extensively studied and used as anticancer drug delivery agents because of their physical properties. This current research aims to prepare water base suspension of uncoated iron oxide nanoparticles and their biodistribution study to different organs, especially the brain, by using a single photon emission computed tomography gamma camera. The water-based suspension of iron oxide nanoparticles was synthesised by a reformed version of the co-precipitation method and labelled with Tc99m for intravenous injection. The nanoparticles were injected without surface modification. X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and transmission electron microscope (TEM) techniques were used for characterisation. Peaks of XRD and EDS indicate that the particles are magnetite and exist in aqueous suspension. The average diameter of iron oxide nanoparticles without any surface coating determined by TEM is 10 nm. These particles are capable of evading the reticuloendothelial system and can cross the blood-brain barrier in the rabbit. The labelling efficiency of iron oxide nanoparticles labelled with Tc99m is 85%, which is good for the biodistribution study. The sufficient amount of iron oxide nanoparticles concentration in the brain as compared with the surrounding soft tissues and their long blood retention time indicates that the water-based suspension of iron oxide nanoparticles may be an option for drug delivery into the brain.

Effect of Flip Angle on the Correlation Between Signal Intensity and Different Concentrations of Iron Oxide Nanoparticles Using T1-Weighted Turbo-FLASH Inversion Recovery Sequence.

Background:Ultrasmall superparamagnetic iron oxide nanoparticles have been used as a blood pool contrast agent for magnetic resonance angiography and perfusion studies. Linear relationship between signal intensity (SI) and nanoparticle concentration is essential for perfusion measurement.Objectives:The aim of this study was to investigate the effect of different flip angles on maximum SI and the linear relationship between SI and different concentrations of iron oxide nanoparticles using T1-weighted Turbo-FLASH (fast low angle shot) inversion recovery sequence to find the optimum flip angle for perfusion measurement.Materials and Methods:This in vitro study was performed using carboxydextran coated iron oxide nanoparticles with 20 nm hydrodynamic size. Different concentrations of nanoparticles between 0 and 500 µmol Fe/L were prepared. MR imaging was performed using T1-weighted Turbo-FLASH inversion recovery sequence. Applied flip angles were 10-45º (interval of 5º). Then the maximum SI resulted by each concentration of nanoparticles was measured. Linear relationship between SI and nanoparticle concentration was evaluated regarding square correlations of 0.95 and 0.99. Coil non-uniformity was considered to obtain accurate SI of each image.Results:The maximum SI was obtained at the highest applied flip angle (45°). The linear relationship between SI and nanoparticle concentration was seen up to 112.21 and 98.83 μmol Fe/L for the short (10°) and the long (45°) flip angles, respectively (R2 = 0.95). These values were reduced up to 48.54 and 42.73 μmol Fe/L for these flip angles with R2 of 0.99.Conclusions:The maximum SI will be increased at higher flip angles with non-linear relationship between SI and nanoparticle concentration. The result shows that an increase in the flip angle leads to a decrease in the range of the linearity. The optimum flip angle which is suitable for perfusion measurement was obtained at 10º for our imaging parameters and sequence. The results of this study may be used in in vivo perfusion measurements.

In situ synthesis of hydroxyapatite nanocomposites using iron oxide nanofluids at ambient conditions.

This paper describes a simple method for the room temperature synthesis of magnetite/hydroxyapatite composite nanocomposites using ferrofluids. The in situ synthesis of magnetic-hydroxyapatite results in a homogenous distribution of the two phases as seen both in transmission electron micrographs and assembled to a micron range in the confocal micrographs. The selected area diffraction pattern analysis shows the presence of both phases of iron oxide and hydroxyapatite. To the dialyzed ferrofluid, the constituents of hydroxyapatite synthesis was added, the presence of the superparamagnetic iron oxide particles imparts directionality to the hydroxyapatite crystal growth. Electron probe microanalysis confirms the co-existence of both iron and calcium atoms. Vibrating Sample magnetometer data shows magnetization three times more than the parent ferrofluid, the local concentration of iron oxide nanoparticles affects the strength of dipolar interparticle interactions changing the energy barrier for determining the collective magnetic behavior of the sample. The limitations inherent to the use of external magnetic fields which can be circumvented by the introduction of internal magnets located in the proximity of the target by a minimal surgery or by using a superparamagnetic scaffold under the influence of externally applied magnetic field inspires us to increase the magnetization of our samples. The composite in addition shows anti-bacterial properties against the two gram (-ve) bacteria tested. This work is significant as magnetite-hydroxyapatite composites are attracting a lot of attention as adsorbents, catalysts, hyperthermia agents and even as regenerative medicine.

Lipoamino Acid Coated Superparamagnetic Iron Oxide Nanoparticles Concentration and Time Dependently Enhanced Growth of Human Hepatocarcinoma Cell Line (Hep-G2)

Superparamagnetic iron oxide nanoparticles (SPION) have been widely used in medicine for magnetic resonance imaging, hyperthermia, and drug delivery applications. The effect of SPION on animal cells has been a controversial issue on which there are many contradictions. This study focused on preparation of SPION with novel biocompatible coatings, their characterization, and cytotoxicity evaluation. An amino acid (glycine) and two novel lipo-amino acids (2 amino-hexanoic acid and 2 amino-hexadecanoic acid) coated magnetic nanoparticles were characterized by various physicochemical means such as X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), differential scanning calorimetry (DSC), and infrared spectroscopy (FT-IR). The cytotoxicity profile of the synthesized nanoparticles on Hep-G2 cells as measured by MTT assay showed the nanoparticles are nontoxic and the cell growth is promoted by SPION. Moreover, lipoamino acid coating SPION appear more beneficial than the other ones. By increasing concentration of SPION, growth enhancing impact will attenuate and toxicity will appear. Although the aggregation of SPION can affect the results, the gradual delivery of ferric/ferrous ions into cells is the main cause of this growth promotion effect. Conclusively, this study shows that lipoamino acid coating SPION can be used for various biomedical purposes.

Accumulation of iron oxide nanoparticles by cultured primary neurons

Magnetic iron oxide nanoparticles (IONPs) are frequently used for biomedical applications. Although nanoparticles can enter the brain, little is known so far on the uptake of IONPs in neurons and on their neurotoxic potential. Hence, we applied dimercaptosuccinate (DMSA)-coated IONPs to cultured primary rat cerebellar granule neurons. These IONPs had average hydrodynamic diameters of around 80 nm and 120 nm when dispersed in incubation medium in the absence and the presence of 10% fetal calf serum, respectively. Acute exposure of neurons with IONPs for up to 6 h did neither alter the cell morphology nor compromise cell viability, although neurons accumulated large amounts of IONPs in a time- and concentration-dependent manner which caused delayed toxicity. For the first 30 min of incubation of neurons at 37 °C with IONPs the cellular iron content increased proportionally to the concentration of IONPs applied irrespective of the absence and the presence of serum. IONP-exposure in the absence of serum generated maximal cellular iron contents of around 3000 nmol iron/mg protein after 4 h of incubation, while the accumulation in the presence of 10% serum was slower and reached already within 1 h maximal values of around 450 nmol iron/mg protein. For both incubation conditions was the increase in cellular iron contents significantly lowered by reducing the incubation temperature to 4 °C. Application of inhibitors of endocytotic pathways did not affect neuronal IONP accumulation in the absence of serum, while inhibitors of clathrin-mediated endocytosis lowered significantly the IONP accumulation in the presence of serum. These data demonstrate that DMSA-coated IONPs are not acutely toxic to cultured neurons and that a protein corona around the particles strongly affects their interaction with neurons.

The Effect of Inversion Time on the Relationship Between Iron Oxide Nanoparticle Concentration and Signal Intensity in T1-Weighted MR Images

Background:Magnetic nanoparticles have been widely applied in recent years for biomedical applications. Signal intensity (SI) of magnetic resonance (MR) images depends on the concentration of nanoparticles. It is important to find the minimum concentration of iron oxide nanoparticles that produces maximum SI and determines the minimum injection dose for clinical studies.Objectives:This study was performed to determine the relationship between the iron oxide nanoparticle concentration and SI using inversion recovery (IR) sequence in T1-weighted MR images.Materials and Methods:Different concentrations of carboxydextran-coated iron oxide nanoparticles 20 nm in size were prepared. In vitro MR imaging was performed with inversion times (TI) of 100-400 ms (interval of 20 ms) and IR Turbo-FLASH (Turbo fast low angle shot) pulse sequence using a 1.5 T MRI system. Then the SI produced by each concentration of nanoparticles was measured and the minimum nanoparticle concentration that led to the maximum SI was determined. Coil non-uniformity was also considered for measuring the accurate SI of each image.Results:The results indicate that SI depended on the concentration of nanoparticles and TI. In addition, SI increased by increasing the TIs ranging from 200 to 400 ms for all studied concentrations. The linear relationship between the nanoparticle concentrations and SI that gave a square correlation coefficient (R2) equal to 0.99 was seen up to 76.83 µmol Fe/L in 400 ms for long TI and 239.16 µmol Fe/L in 200 ms for short TI.Conclusions:TI is an important parameter to consider in the relationship between SI and nanoparticle concentrations. An increase in TI leads to a decrease in the range of linearity.

Impacts of Iron Oxide Nanoparticles on the Invasion Power of Listeria monocytogenes

Recently, magnetic nanoparticles have been introduced as a novel antimicrobial material. Listeria monocytogenes are the causative agent of listeriosis and stands among the major public health issues. This bacterium can attach to the host cell membrane and trigger molecular responses leading to phagocytosis of the bacterial cell. In the present study, the effect of iron oxide nanoparticles (IONs) on the invasion power of L. monocytogenes was investigated. IONs were synthesized by coprecipitation method and coated with 3-aminopropyltriethoxysilane (APTES). Listeria monocytogenes cells were exposed to the prepared particles and interactions between IONs and bacterial cells were visualized by scanning electron microscopy. Invasion power of listerial cells for penetration HepG-2 cells monolayer was also examined in various concentrations of IONs. IONs have reduced invasion power of L. monocytogenes in a concentration-dependent manner. Almost 4-fold reduction in the invasion power of L. monocytogenes was observed at 20 µg ml-1 IONs concentration. Keywords: Antibacterial, 3-aminopropyltriethoxysilane (APTES), Listeria monocytogenes, magnetic nanoparticles, pathogenesis.

Quantifying iron‐oxide nanoparticles at high concentration based on longitudinal relaxation using a three‐dimensional SWIFT look‐locker sequence

Iron-oxide nanoparticles (IONPs) have proven utility as contrast agents in many MRI applications. Previous quantitative IONP mapping has been performed using mainly T2 * mapping methods. However, in applications requiring high IONP concentrations, such as magnetic nanoparticles based thermal therapies, conventional pulse sequences are unable to map T2 * because the signal decays too rapidly. In this article, sweep imaging with Fourier transformation (SWIFT) sequence is combined with the Look-Locker method to map T1 of IONPs in high concentrations. T1 values of agar containing IONPs in different concentrations were measured with the SWIFT Look-Locker method and with inversion recovery spectroscopy. Precisions of Look-Locker and variable flip angle (VFA) methods were compared in simulations. The measured R1 (=1/T1 ) has a linear relationship with IONP concentration up to 53.6 mM of Fe. This concentration exceeds concentrations measured in previous work by almost an order of magnitude. Simulations show SWIFT Look-Locker method is also much less sensitive to B1 inhomogeneity than the VFA method. SWIFT Look-Locker can accurately measure T1 of IONP concentrations ≤53.6 mM. By mapping T1 as a function of IONP concentration, IONP distribution maps might be used in the future to plan effective magnetic nanoparticle hyperthermia therapy.

Kinetics of Nano-catalysed Dark Fermentative Hydrogen Production from Distillery Wastewater

Kinetics of nano-catalysed dark fermentative biohydrogen production from molasses-based distillery wastewater has been reported. Iron oxide nanoparticle was supplemented (10-200 mgL-1) to the wastewater to enhance the biohydrogen production. Andrew's inhibition model was employed to evaluate the rate of hydrogen production (RH2) and hydrogen yield at different concentration of iron oxide nanoparticles. The maximum RH2 and specific hydrogen yield (SHY) for the fermentative hydrogen production system at different concentration of iron oxide nanoparticle were found to be 80.7ml/hr and 44.28ml H2/g COD. Michaelis-Menton equation was applied to determine the rate of hydrogen production (RH2) and yield of H2 (SHY) at different initial pH (5, 6 & 7). Andrew's inhibition model has been used to describe the inhibitory effect of substrate concentration on the rate of H2 production (RH2). RH2 decreased with the increase in substrate concentration but SHY first decreased with substrate concentration and it is maximum at higher substrate concentration of 110 gL-1. Monod model has been used to determine the growth kinetic parameters. The values of maximum rates of microbial growth (μm) and substrate utilization (Rsu) were 0.1g biomass/g biomass/day and 14.03g COD/g biomass/day respectively at different iron oxide nanoparticles concentration.

Antibacterial Efficacy of Iron-Oxide Nanoparticles against Biofilms on Different Biomaterial Surfaces.

Biofilm growth on the implant surface is the number one cause of the failure of the implants. Biofilms on implant surfaces are hard to eliminate by antibiotics due to the protection offered by the exopolymeric substances that embed the organisms in a matrix, impenetrable for most antibiotics and immune cells. Application of metals in nanoscale is considered to resolve biofilm formation. Here we studied the effect of iron-oxide nanoparticles over biofilm formation on different biomaterial surfaces and pluronic coated surfaces. Bacterial adhesion for 30 min showed significant reduction in bacterial adhesion on pluronic coated surfaces compared to other surfaces. Subsequently, bacteria were allowed to grow for 24 h in the presence of different concentrations of iron-oxide nanoparticles. A significant reduction in biofilm growth was observed in the presence of the highest concentration of iron-oxide nanoparticles on pluronic coated surfaces compared to other surfaces. Therefore, combination of polymer brush coating and iron-oxide nanoparticles could show a significant reduction in biofilm formation.

Decolourisation of Direct Orange S dye by ultra sonication using iron oxide nanoparticles

Biosynthesised iron oxide nanoparticles (INPs) less than 100 nm were used to decolourise the textile dye, Direct Orange S by the process of ultra sonication. The parameters tested for the decolourisation of the Direct Orange S dye were the INP concentration (0.2–1g/l), pH (3–11) and H2O2 concentration (2–8 ml/l). The rate of decolourisation process was performed by both stirrer and ultra sonicator method using the first-order kinetics ln(c/c0). The percentage of dye removal for the optimum conditions such as INP, 1g/l (87.2%); pH, 9 (85.5%) and H2O2 concentration 8 ml/l (86.5%) were observed. The Direct Orange S dye was degraded efficiently by sonolysis (60 min) than by the magnetic stirrer method (120 min). High-performance liquid chromatography results showed that the peak for Direct Orange S dye was not present when the dye sample was treated by either H2O2 + INP or INP alone. Use of biosynthesised iron NPs in Direct Orange S dye (azo dye) decolourisation by a simple non-toxic Fenton reaction is a safe and novel approach. Industrialisation of this technique will be an economical way to decolorise the textile dyes present in water systems.

Iron oxide nanoparticle enhancement of radiation cytotoxicity.

Iron oxide nanoparticles (IONPs) have been investigated as a promising means for inducing tumor cell-specific hyperthermia. Although the ability to generate and use nanoparticles that are biocompatible, tumor specific, and have the ability to produce adequate cytotoxic heat is very promising, significant preclinical and clinical development will be required for clinical efficacy. At this time it appears using IONP-induced hyperthermia as an adjunct to conventional cancer therapeutics, rather than as an independent treatment, will provide the initial IONP clinical treatment. Due to their high-Z characteristics, another option is to use intracellular IONPs to enhance radiation therapy without excitation with AMF (production of heat). To test this concept IONPs were added to cell culture media at a concentration of 0.2 mg Fe/mL and incubated with murine breast adenocarcinoma (MTG-B) cells for either 48 or 72 hours. Extracellular iron was then removed and all cells were irradiated at 4 Gy. Although samples incubated with IONPs for 48 hrs did not demonstrate enhanced post-irradiation cytotoxicity as compared to the non-IONP-containing cells, cells incubated with IONPs for 72 hours, which contained 40% more Fe than 48 hr incubated cells, showed a 25% decrease in clonogenic survival compared to their non-IONP-containing counterparts. These results suggest that a critical concentration of intracellular IONPs is necessary for enhancing radiation cytotoxicity.

Iron oxide nanoparticle-based radio-frequency thermotherapy for human breast adenocarcinoma cancer cells.

Iron oxide nanoparticles (IONPs) with diameters of 15, 25, and 41 nm were evaluated as mediators of thermal cytotoxicity under radio-frequency (RF) exposure. The 25 nm IONPs were found to be the most efficient of the three in killing cancer cells at 350 kHz low-frequency RF irradiation. However, at a higher frequency of 13.56 MHz, 15 nm IONPs produced the highest percentage of cell death. Moreover, the killing effect was concentration-dependent in that a higher concentration of IONPs resulted in increased cellular death. Size-dependent internalization of IONPs in MCF-7 cells was quantified by using inductively coupled-plasma mass spectrometry (ICP-MS). Dark-field microscopy and transmission electron microscopy (TEM) revealed that MCF-7 cells internalize IONPs through endocytosis after 24 hours of incubation. In addition, after RF treatment, the cancer cells underwent the apoptosis process, and the level of reactive oxygen species (ROS) increased significantly after hyperthermia. Scanning electron microscopy (SEM) and TEM further established that the ultrastructure morphological changes in the cancer cells originated from the apoptosis process.

Toward absolute quantification of iron oxide nanoparticles as well as cell internalized fraction using multiparametric MRI

Iron oxide nanoparticles (IONPs) are widely used as MR contrast agents because of their strong magnetic properties and broad range of applications. The contrast induced by IONPs typically depends on concentration, water accessibility, particle size and heterogeneity of IONP distribution within the microenvironment. Although the latter could be a tool to assess local physiological effects at the molecular level, it renders IONP quantification from relaxation measurements challenging. This study aims to quantify IONP concentration using susceptibility measurements. In addition, further analysis of relaxation data is proposed to extract quantitative information about the IONP spatial distribution. Mesenchymal stem cells were labeled with IONPs and the IONP concentration measured by mass spectroscopy. MR relaxation parameters (T(1), T(2), T(2)*) as well as magnetic susceptibility of cylindrical samples containing serial dilutions of mixtures of free and cell-internalized IONPs were measured and correlated with IONP concentration. Unlike relaxation data, magnetic susceptibility was independent of whether IONPs were free or internalized, making it an excellent candidate for IONP quantification. Using IONP concentration derived from mass spectroscopy and measured relaxation times, free and internalized IONP fractions were accurately calculated. Magnetic susceptibility was shown to be a robust technique to measure IONP concentration in this preliminary study. Novel imaging-based susceptibility mapping techniques could prove to be valuable tools to quantify IONP concentration directly by MRI, for samples of arbitrary shape. Combined with relaxation time mapping techniques, especially T(2) and T(2)*, this could be an efficient way to measure both IONP concentration and the internalized IONP fraction in vivo using MRI, to gain insight into tissue function and molecular imaging paradigms.

Image-guided targeted intraarterial delivery of chemotherapy drug loaded iron oxide nanoparticles to rabbit liver cancer model.

e14734 Background: To develop an enhanced drug delivery system to liver tumors using novel MRI traceable iron oxide nanoparticles (IONP) loaded with doxorubicin and to investigate biodistribution of deliverednanoparticle and by assessing intratumoral and normal liver tissue concentrations after targeted (IA) versus systemic (IV) administration. Methods: Paramagnetic IONP (core and hydrodynamic size of 10 nm and 23 nm, respectively) coated with amphiphilic polymers were non-covalently loaded with hydrophobic doxorubicin; whose presence was confirmed by optical absorption spectrum. VX2 liver tumors were induced in the left lobe of 12 rabbits, allowed to grow for 2 weeks to a size of 2 cm, and were subsequently divided into 2 treatment groups, each receiving 1 mg/kg body weight of doxorubicin via IONP. Group 1 received IA administration to the left hepatic artery under fluoroscopy, and Group 2 received IV administration via the marginal ear vein. Animals were sacrificed 24 hours after treatment. Tumor and liver sections were collected and iron concentrations of tumor and liver tissues were determined by the colorimetric method with iron binding 1,10-phenanthroline at 508 nm. Analysis of tissue iron concentrations in different groups was performed using a standard t-test, with p<0.05 considered significant. Results: Intratumoral and peritumoral concentrations of IONP were significantly higher 24 hours after IA administration than IV (1.54 vs 1.03 mg Fe/g , p=0.019), given at the same dosage. Additionally, 24 hours after treatment, the group receiving IA therapy showed significantly higher nanoparticle concentrations in the left hepatic lobe in comparison to the IV group (1.63 vs 1.34 mg Fe/g, p=0.0226). Conclusions: Targeted IA delivery significantly enhances intratumoral and peritumoral uptake of IONP when compared to IV. Targeted intraarterial delivery of IONP carrying doxorubincin can serve as a powerful tool in serving as a vehicle to deliver chemotherapy drugs to liver tumors. To further evaluate the potential of this drug delivery method, future studies will correlate the biodistrubution of the IONP to drug concentrations and findings on histology, imaging, tumor response.

Preparation and characterization of magnetic nanofibers with iron oxide nanoparticles and poly(ethylene terephthalate)

AbstractIron oxide nanoparticle/Poly(ethylene terephthalate) (PET) nanowebs were obtained by electrospinning. To achieve superparamagnetic properties, iron oxide nanoparticles with diameters below 25 nm were used. Diameter distribution of iron oxide nanoparticles was measured by a particle size analyzer. Iron oxide nanoparticles were added into 16 wt % PET solution in the ratio of 5, 10, and 15 wt % to PET. The morphology of iron oxide nanoparticle/PET nanowebs was observed using field emission‐scanning electron microscopy (FE‐SEM) and transmission electron microscopy (TEM). The nanofiber diameter increased as increasing iron oxide nanoparticle concentration. The superparamagnetic behavior of iron oxide nanoparticle/PET nanofiber was confirmed using superconducting quantum interference device (SQUID). The degree of crystallinity of iron oxide nanoparticle/PET nanowebs was calculated from a differential scanning calorimeter (DSC) results. The change of flexural rigidity and tensile properties of electrospun iron oxide nanoparticle/PET nanowebs with the external magnetic field were examined ISO 9073‐7 testing method, universal testing machine and an appropriate magnet. Also, the elastic modulus of iron oxide nanoparticle/PET nanofiber was measured using nanoindentation. With applying magnetic field, the improvement in mechanical properties of field‐responsive magnetic nanofibers and nanowebs was confirmed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Facile One-Pot Synthesis of Iron Oxide Nanoparticles Cross-linked Magnetic Poly(vinyl alcohol) Gel Beads for Drug Delivery

In this paper, a facile one-pot strategy for scalable synthesis of robust magnetic poly(vinyl alcohol) (mPVA) gel beads is developed. Through dropwise addition of mixed aqueous solution of iron salts and PVA solution into alkaline (e.g., ammonia, NaOH, and KOH) solution, mPVA gel beads with uniform size and excellent superparamagnetic property can be fabricated based on the simultaneous formation of magnetic iron oxide nanoparticles (MIONs) and cross-link of PVA chains. Moreover, this approach can be extended to prepare dual- or multiresponsive gel beads through simply adding functional fillers into PVA solution (e.g., mPVA-PNIPAM gel beads that possess both magnetic and temperature responsibilities can be readily prepared by adding temperature responsive poly(N-isopropylacrylamide) (PNIPAM) into PVA solution). It is found that that the obtained mPVA gel beads exhibit high drug loading level (e.g., above 70%) after the treatment of freezing-thawing. Drug release experiments reveal that the drug release rate and amount of the mPVA gel beads can be tuned by operating the external magnetic field and adjusting the concentration of iron oxide nanoparticles and temperature (for mPVA-PNIPAM gel beads). The present work is of interest for opening up enormous opportunities to make full use of magnetic gel beads in drug delivery and other applications, because of their facile availability, cost-effective productivity, and tunable drug release performance.

Iron Oxide Nanoparticles Conjugated Monoclonal Antibody for Immunochromatographic Strip Test

In this study, the synthesis of iron oxide nanoparticles (IONPs) and immunochromatographic (ICG) strip test of iron oxide conjugated with monoclonal antibody (IONPs-Ab) have been developed. The IONPs were synthesised using precipitation method and dispersed in water by applying polyethylene glycol coating. Several parameters that affected conjugations of the IONPs-Ab were studied namely iron oxide concentration, antibody volume, stabilizer concentration and the amount of SiPEG coating. From the transmission electron microscopy (TEM) image, the size of IONPs obtained was ~14 nm. Conjugate was tested with the ICG strip test lined with the antigen. The results showed 1.0μl SiPEG coating, 1 M IONPs concentration, 20μl of 1mg/ml antibody volume and 1% bovine serum albumin (BSA) were the optimum. Moreover, the IONPs-Ab was also tested with the Brugian filariasis positive and negative serum samples. The results showed positive result for the patient serum and negative result for the non-patient serum in just 15 minutes.

Treatment with iron oxide nanoparticles induces ferritin synthesis but not oxidative stress in oligodendroglial cells

Magnetic iron oxide nanoparticles (IONPs) have been used for a variety of neurobiological applications, although little is yet known as to the fate of such particles in brain cells. To address these questions, we have exposed oligodendroglial OLN-93 cells to dimercaptosuccinate-coated IONPs. Treatment of the cells strongly increased the specific cellular iron content proportional to the IONP concentrations applied (0–1000 μM total iron as IONPs) up to 300-fold, but did not cause any acute cytotoxicity or induce oxidative stress. To investigate the potential of OLN-93 cells to liberate iron from the accumulated IONPs, we have studied the upregulation of the iron storage protein ferritin and the cell proliferation as cellular processes that depend on the availability of low-molecular-weight iron. The presence of IONPs caused a concentration-dependent increase in the amount of cellular ferritin and partially bypassed the inhibition of cell proliferation by the iron chelator deferoxamine. These data demonstrate that viable OLN-93 cells efficiently take up IONPs and suggest that these cells are able to use iron liberated from accumulated IONPs for their metabolism.

Characterization of the Biocompatible Magnetic Colloid on the Basis of Fe<SUB>3</SUB>O<SUB>4</SUB> Nanoparticles Coated with Dextran, Used as Contrast Agent in Magnetic Resonance Imaging

The magnetic resonance imaging contrast agent, the so-called Endorem colloidal suspension on the basis of superparamagnetic iron oxide nanoparticles (mean diameter of 5.5 nm) coated with dextran, were characterized on the basis of several measurement techniques to determine the parameters of their most important physical and chemical properties. It is assumed that each nanoparticle is consisted of Fe3O4 monodomain and it was observed that its oxidation to gamma-Fe2O3 occurs at 253.1 degrees C. The Mössbauer spectroscopy have shown a superparamagnetic behavior of the magnetic nanoparticles. The Magnetic Resonance results show an increase of the relaxation times T1, T2, and T2* with decreasing concentration of iron oxide nanoparticles. The relaxation effects of SPIONs contrast agents are influenced by their local concentration as well as the applied field strength and the environment in which these agents interact with surrounding protons. The proton relaxation rates presented a linear behavior with concentration. The measured values of thermo-optic coefficient dn/dT, thermal conductivity kappa, optical birefringence delta n0, nonlinear refractive index n2, nonlinear absorption beta' and third-order nonlinear susceptibility |chi(3)| are also reported.