Anti-CEA-functionalized superparamagnetic iron oxide nanoparticles for examining colorectal tumors in vivo

Although the biomarker carcinoembryonic antigen (CEA) is expressed in colorectal tumors, the utility of an anti-CEA-functionalized image medium is powerful for in vivo positioning of colorectal tumors. With a risk of superparamagnetic iron oxide nanoparticles (SPIONPs) that is lower for animals than other material carriers, anti-CEA-functionalized SPIONPs were synthesized in this study for labeling colorectal tumors by conducting different preoperatively and intraoperatively in vivo examinations. In magnetic resonance imaging (MRI), the image variation of colorectal tumors reached the maximum at approximately 24 h. However, because MRI requires a nonmetal environment, it was limited to preoperative imaging. With the potentiality of in vivo screening and intraoperative positioning during surgery, the scanning superconducting-quantum-interference-device biosusceptometry (SSB) was adopted, showing the favorable agreement of time-varied intensity with MRI. Furthermore, biological methodologies of different tissue staining methods and inductively coupled plasma (ICP) yielded consistent results, proving that the obtained in vivo results occurred because of targeted anti-CEA SPIONPs. This indicates that developed anti-CEA SPIONPs owe the utilities as an image medium of these in vivo methodologies.     

Magnetic properties of superparamagnetic nanoparticles loaded into silicon nanotubes

In this work, the magnetic properties of silicon nanotubes (SiNTs) filled with Fe₃O₄ nanoparticles (NPs) are investigated. SiNTs with different wall thicknesses of 10 and 70 nm and an inner diameter of approximately 50 nm are prepared and filled with superparamagnetic iron oxide nanoparticles of 4 and 10 nm in diameter. The infiltration process of the NPs into the tubes and dependence on the wall-thickness is described. Furthermore, data from magnetization measurements of the nanocomposite systems are analyzed in terms of iron oxide nanoparticle size dependence. Such biocompatible nanocomposites have potential merit in the field of magnetically guided drug delivery vehicles.

PACS

61.46.Fg; 62.23.Pq; 75.75.-c; 75.20.-g     

The cytotoxicity evaluation of magnetic iron oxide nanoparticles on human aortic endothelial cells

One major obstacle for successful application of nanoparticles in medicine is its potential nanotoxicity on the environment and human health. In this study, we evaluated the cytotoxicity effect of dimercaptosuccinic acid-coated iron oxide (DMSA-Fe₂O₃) using cultured human aortic endothelial cells (HAECs). Our results showed that DMSA-Fe₂O₃ in the culture medium could be absorbed into HAECs, and dispersed in the cytoplasm. The cytotoxicity effect of DMSA-Fe₂O₃ on HAECs was dose-dependent, and the concentrations no more than 0.02 mg/ml had little toxic effect which were revealed by tetrazolium dye assay. Meanwhile, the cell injury biomarker, lactate dehydrogenase, was not significantly higher than that from control cells (without DMSA-Fe₂O₃). However, the endocrine function for endothelin-1 and prostacyclin I-2, as well as the urea transporter function, was altered even without obvious evidence of cell injury in this context. We also showed by real-time PCR analysis that DMSA-Fe₂O₃ exposure resulted in differential effects on the expressions of pro- and anti-apoptosis genes of HAECs. Meanwhile, it was noted that DMSA-Fe₂O₃ exposure could activate the expression of genes related to oxidative stress and adhesion molecules, which suggested that inflammatory response might be evoked. Moreover, we demonstrated by in vitro endothelial tube formation that even a small amount of DMSA-Fe₂O₃ (0.01 and 0.02 mg/ml) could inhibit angiogenesis by the HAECs. Altogether, these results indicate that DMSA-Fe₂O₃ have some cytotoxicity that may cause side effects on normal endothelial cells.     

Multifunctional liposomal drug delivery with dual probes of magnetic resonance and fluorescence imaging

Many liposomal drug carriers have shown great promise in the clinic. To ensure the efficient preclinical development of drug-loaded liposomes, the drug retention and circulation properties of these systems should be characterized. Iron oxide (Fe₃O₄) magnetic nanoparticles (MNPs) are used as T2 contrast agents in magnetic resonance imaging (MRI). Gold nanoclusters (GNCs) contain tens of atoms with subnanometer dimensions; they have very low cytotoxicity and possess superb red emitting fluorescent properties, which prevents in vivo background autofluorescence. The aim of this study was to develop dual imaging, nanocomposite, multifunctional liposome drug carriers (Fe₃O₄-GNCs) comprising MNPs of iron oxide and GNCs. First, MNPs of iron oxide were synthesized by co-precipitation. The MNP surfaces were modified with amine groups using 3-aminopropyltriethoxysilane (APTES). Second, GNCs were synthesized by reducing HAuCl₄·3H₂O with NaBH4 in the presence of lipoic acid (as a stabilizer and nanosynthetic template). The GNCs were grown by adsorption onto particles to control the size and stability of the resultant colloids. Subsequently, dual Fe₃O₄-GNCs imaging probes were fabricated by conjugating the iron oxide MNPs with the GNCs via amide bonds. Finally, liposome nanocarriers were used to enclose the Fe₃O₄-GNCs in an inner phase (liposome@Fe₃O₄-GNCs) by reverse phase evaporation. These nanocarriers were characterized by dynamic light scattering (DLS), fluorescence spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectrophotometry, superconducting quantum interference device (SQUID), nuclear magnetic resonance (NMR) imaging and in vivo imaging systems (IVIS). These multifunctional liposomal drug delivery systems with dual probes are expected to prove useful in preclinical trials for cancer diagnosis and therapy.     

Green facile synthesis of low-toxic superparamagnetic iron oxide nanoparticles (SPIONs) and their cytotoxicity effects toward Neuro2A and HUVEC cell lines

Superparamagnetic iron oxide (Fe₃O₄) nanoparticles (SPIONs) were synthesized by co-precipitation using polyvinyl alcohol (PVA) as a capping agent under alkaline condition. The produced X-ray diffraction (XRD) pattern evidenced the presence of peaks corresponding to the inverse spinel structure of the prepared SPIONs. Debye-Scherrer and field emission scanning microscopy (FESEM) showed the prepared SPIONs to be well-defined with about <?50?nm size. Likewise, the superparamagnetic properties of the SPIONs measured by Vibrating Sample Magnetometer (VSM) showed high saturation magnetization (~ 65.36?emu/g). The in vitro cytotoxicity studies on Neuro2A and HUVEC cells have mentioned low toxic and non-toxic SPIONs, respectively in a range of concentrations (1.17–150?μg/ml), thus, we reckon that the synthesized SPIONs will have persistent utilization in different fields of medical applications.     

Structural and magnetic characterization of norbornene-deuterated norbornene dicarboxylic acid diblock copolymers doped with iron oxide nanoparticles

A series of iron oxide doped norbornene (NOR)/deuterated norbornene dicarboxylic acid (NORCOOH) diblock copolymers were synthesized and characterized by X-ray photoelectron spectroscopy (XPS), small angle neutron scattering (SANS) and superconducting quantum interference device (SQUID) experiments. γ-Fe₂O₃ nanoparticles were synthesized within the microdomains of diblock copolymers with volume fractions of NOR/NORCOOH 0.64/0.36, 0.50/0.50 and 0.40/0.60. A spherical nanoparticle morphology was displayed in the polymer with 0.64/0.36 volume fraction. Polymers with 0.50/0.50 and 0.40/0.60 volume fractions exhibited interconnected metal oxide nanostructures. The observed changes in the shape and peak positions of the small-angle neutron scattering profiles of polymers after metal doping were related to the scattering from the metal oxide particles and to the possible deformed morphologies due to the strong interparticle interactions between metal particles, which may influence the polymer microphase separation. The combined scattering from both polymer domains and magnetic particles was depicted in SANS profiles of metal oxide doped polymers. γ-Fe₂O₃ containing block copolymers were superparamagnetic at room temperature. An increase in the blocking temperature (T_b) of interconnected nanoparticles was observed and was related to the interparticle interactions, which depends on the average distance (d) between particles and individual particle diameter (2R). The sample with volume fraction of 0.4/0.6 have the lowest d/(2R) ratio and exhibit the highest T_b at 115 K.     

Effects of irradiation energy and nanoparticle concentrations on the structure and morphology of laser sintered magnesia with alumina and iron oxide nanoparticles

The laser sintering mechanism of composites based on magnesia and oxide nanoparticles was studied in terms of nanoparticle concentration and laser energy fluence. Iron oxide and aluminum oxide nanoparticles were mechanically mixed with magnesia (MgO) powder (5, 7 and 10 wt%) and the compacted pellets were irradiated with the fundamental output (1064 nm) of a pulsed Nd:YAG laser at 2.5 and 3.0 J/cm². Crystal structure, elemental composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. X-ray diffraction results confirmed the crystalline phases and spinel formation by addition of oxide nanoparticles and laser sintering. X-ray photoelectron spectroscopy analysis confirmed their surface composition and chemical states of the corresponding elements. Morphological changes were observed due to the laser fluence and the oxide nanoparticle concentrations. Results show that a coarsening mechanism was predominant with a high energy fluence and concentration of oxide nanoparticles.     

Crystallization and magnetic property of iron oxide nanoparticles precipitated in silica glass matrix

Crystallization and magnetic property of Fe₂O₃ nanoparticle precipitated in SiO₂ matrix was investigated. Fe₂O₃/SiO₂ nanocomposite thin film was obtained by annealing of the amorphous Fe-Si-O thin film deposited by RF-magnetron sputtering of (α-Fe₂O₃)_1−x/(SiO₂)_x composite targets. The Fe₂O₃ crystallite size increased with decreasing SiO₂ area ratio, x of the target and increasing annealing temperature. ?-Fe₂O₃ with the crystallite size of 20-30 nm was obtained after annealing the film deposited in SiO₂ area ratio, x = 0.33-0.42 at 900 °C. Lower SiO₂ area ratio (x) than 0.25 and higher annealing temperature resulted in precipitation of α-Fe₂O₃ with the larger crystallite size than 40 nm. In the case of SiO₂ area ratio, x ≥ 0.50, the annealed film was amorphous and showed higher magnetization and smaller coercivity due to the precipitation of very small crystalline γ-Fe₂O₃. The ?-Fe₂O₃/SiO₂ composite thin film showed ferromagnetic hysteresis with coercive force of 0.14 T.     

Synthesis of in situ functionalized iron oxide nanoparticles presenting alkyne groups via a continuous process using near-critical and supercritical water

The preparation of iron oxide nanoparticle dispersions of varying properties (e.g. color, crystal structure, particle size distribution) in a continuous hydrothermal pilot plant operating under near-critical and supercritical conditions with the aim of producing in situ functionalized nanoparticles suitable for secondary functionalization via click chemistry is reported. The effect of varying the mixing setup, reaction temperature and the starting material (iron salt) in the presence of different carboxylic acids on the resulting nanoparticle dispersions was investigated. The stability of the clickable ligands in the harsh hydrothermal environment was also tested and the clickability of the functionalized particles was demonstrated by means of XPS and fluorescence measurements after model click reactions.     

TEM characterization of diblock copolymer templated iron oxide nanoparticles: Bulk solution and thin film surface doping approach

The morphology of a novel diblock copolymer, poly(norbornene methanol)-b-poly(norbornene dicarboxylic acid), was investigated before and after metal oxide doping by transmission electron microscopy (TEM) using a novel iodine vapor staining method to image the undoped polymer. A lamellar morphology was observed by TEM after staining the undoped diblock copolymer with iodine vapor. Thin film surface doping resulted in a confinement of the iron oxide nanoparticles within the lamellar domains. Spherical nanoparticle aggregates were observed through a bulk solution doping method. It was observed that the particles were templated by the underlying lamellar structure of the copolymer when the thin film surface doping method was used.     

Magnetic resonance imaging studies of the polymerisation of methylmethacrylate

Magnetic resonance imaging has been used to spatially map the time course of the bulk polymerisation of methylmethacrylate. Both two-dimensional projection and slice-selective techniques have been employed. Image intensities give qualitative information about viscosity, reaction rates and the localised extent of polymerisation. The importance of proton relaxation measurements in drawing quantitative conclusions is stressed.     

Size-regulated group separation of CoFe2O4 nanoparticles using centrifuge and their magnetic resonance contrast properties

Magnetic nanoparticle (MNP)-based magnetic resonance imaging (MRI) contrast agents (CAs) have been the subject of extensive research over recent decades. The particle size of MNPs varies widely and is known to influence their physicochemical and pharmacokinetic properties. There are two commonly used methods for synthesizing MNPs, organometallic and aqueous solution coprecipitation. The former has the advantage of being able to control the particle size more effectively; however, the resulting particles require a hydrophilic coating in order to be rendered water soluble. The MNPs produced using the latter method are intrinsically water soluble, but they have a relatively wide particle size distribution. Size-controlled water-soluble MNPs have great potential as MRI CAs and in cell sorting and labeling applications. In the present study, we synthesized CoFe₂O₄ MNPs using an aqueous solution coprecipitation method. The MNPs were subsequently separated into four groups depending on size, by the use of centrifugation at different speeds. The crystal shapes and size distributions of the particles in the four groups were measured and confirmed by transmission electron microscopy and dynamic light scattering. Using X-ray diffraction analysis, the MNPs were found to have an inverse spinel structure. Four MNP groups with well-selected semi-Gaussian-like diameter distributions were obtained, with measured T₂ relaxivities (r₂) at 4.7 T and room temperature in the range of 60 to 300 mM⁻¹s⁻¹, depending on the particle size. This size regulation method has great promise for applications that require homogeneous-sized MNPs made by an aqueous solution coprecipitation method. Any group of the CoFe₂O₄ MNPs could be used as initial base cores of MRI T₂ CAs, with almost unique T₂ relaxivity owing to size regulation. The methodology reported here opens up many possibilities for biosensing applications and disease diagnosis.

PACS

75.75.Fk, 78.67.Bf, 61.46.Df     

Pullulan: A versatile coating agent for superparamagnetic iron oxide nanoparticles

Ultrasmall superparamagnetic iron oxide (Fe₃O₄) nanoparticles coated by biocompatible pullulan (Pu‐USPIO) with sizes below 10 nm and having a magnetite core and a hydrophilic outer shell of pullulan were prepared. The formed Pu‐USPIOs were thoroughly characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, atomic force microscopy, and small‐angle X‐ray scattering experiments. The content of magnetic nanoparticles embedded into the pullulan matrix was determined by thermogravimetric analysis. Vibrating sample magnetometry analysis was used to evaluate the magnetic properties of the Pu‐USPIO samples. Because of the presence of pullulan, these nanoparticles could be conditioned in many versatile forms, from a clear solution to magnetic films, for potential applications, including magnetic hyperthermia mediators. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42926.     

Graphene oxide impregnated with iron oxide nanoparticles for the removal of atrazine from the aqueous medium

ABSTRACT

The present study proposes development of an adsorbent based on combination of graphene oxide (GO) and iron oxide (α-γ-Fe₂O₃) nanoparticles for atrazine removal from water. The synthesized adsorbent (GO@ α-γ-Fe₂O₃) was characterized using different techniques. Magnetic measurements proved that the adsorbent has superparamagnetic characteristics, thus facilitating its magnetic separation from the working suspensions. The maximum adsorption capacity was 42.5 mg g^?1. The Langmuir isotherm and the pseudo-second order kinetic models correlated adequately with the experimental data. The thermodynamic data showed that atrazine adsorption was spontaneous, endothermic and thermodynamically favorable.     

The Effect of Iron Oxide Magnetic Nanoparticles on Smooth Muscle Cells

Recently, magnetic nanoparticles of iron oxide (Fe₃O₄, γ-Fe₂O₃) have shown an increasing number of applications in the field of biomedicine, but some questions have been raised about the potential impact of these nanoparticles on the environment and human health. In this work, the three types of magnetic nanoparticles (DMSA-Fe₂O₃, APTS-Fe₂O₃, and GLU-Fe₂O₃) with the same crystal structure, magnetic properties, and size distribution was designed, prepared, and characterized by transmission electronic microscopy, powder X-ray diffraction, zeta potential analyzer, vibrating sample magnetometer, and Fourier transform Infrared spectroscopy. Then, we have investigated the effect of the three types of magnetic nanoparticles (DMSA-Fe₂O₃, APTS-Fe₂O₃, and GLU-Fe₂O₃) on smooth muscle cells (SMCs). Cellular uptake of nanoparticles by SMC displays the dose, the incubation time and surface property dependent patterns. Through the thin section TEM images, we observe that DMSA-Fe₂O₃ is incorporated into the lysosome of SMCs. The magnetic nanoparticles have no inflammation impact, but decrease the viability of SMCs. The other questions about metabolism and other impacts will be the next subject of further studies. Song Zhang and Xiangjian Chen contributed equally to this work.     

Magnetic resonance imaging of crack formation in hydrated cement paste materials

A magnetic resonance imaging (MRI) methodology is presented to spatially resolve cracking in hydrated cement paste. The method is based on the relatively long spin-lattice (T₁) and spin-spin relaxation (T₂) times (magnetic resonance signal lifetimes) associated with water-filled cracks. Water-filled capillary and gel pores have much shorter signal lifetimes. As a noninvasive method, the technique may be used to study crack formation and propagation in well-controlled laboratory test samples. The method is proven to be capable of spatially resolving crack structures with widths of tens of micrometers.     

Effect of iron oxide nanoparticles on the morphological properties of isotactic polypropylene

Isotactic polypropylene (iPP) and iron oxide (Fe₃O₄) nanocomposites were mixed by masterbatch blending technique in a single screw extruder machine. The concentrations of Fe₃O₄ in the iPP/Fe₃O₄ nanocomposites were 0.5, 1, 2, and 5% by weight. The influence of Fe₃O₄ nanoparticles on the effectiveness of nucleation, morphology, mode of crystallization, and crystallinity of iPP were studied by differential scanning calorimetry (DSC) and polarized light microscopy (PLM). The introduction of Fe₃O₄ nanoparticles in the iPP matrix inhibited the formation of β crystals, and caused a shift in the melting point to higher values. The magnitude of the shift was up to 20–21°C which indicates that using the masterbatch technique leads to an enhancement of the dispersion process of the Fe₃O₄ nanoparticle and the formation of less agglomerates in the iPP/Fe₃O₄ nanocomposites. The percentage crystallinity, X_c, increased at the low cooling rates of 1 and 2°C/min. At higher cooling rates of 5, 10, and 20°C/min, the masterbatch technique produced nanocomposites of X_c with nonuniform trends. The overall crystallization rate enhancement for the iPP/Fe₃O₄ nanocomposites is attributed to the presence of Fe₃O₄ nanoparticles as a nucleating agent which have no significant effect on the growth rate of iPP crystals. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010