Magnetic nanoparticles in magnetic resonance imaging and diagnostics

Classification and applications of nanomaterials in vitro diagnosis

With the rapid development of clinical diagnosis and treatment, many traditional and conventional in vitro diagnosis technologies are unable to meet the demands of clinical medicine development. In this situation, nanomaterials are rapidly developing and widely used in the field of in vitro diagnosis. Nanomaterials have distinct size-dependent physical or chemical properties, and their optical, magnetic, electrical, thermal, and biological properties can be modulated at the nanoscale by changing their size, shape, chemical composition, and surface functional groups, particularly because they have a larger specific surface area than macromaterials. They provide an amount of space to modify different molecules on their surface, allowing them to detect small substances, nucleic acids, proteins, and microorganisms. Combining nanomaterials with in vitro diagnosis is expected to result in lower detection limits, higher sensitivity, and stronger selectivity. In this review, we will discuss the classfication and properties of some common nanomaterials, as well as their applications in protein, nucleic acids, and other aspect detection and analysis for in vitro diagnosis, especially on aging-related nanodiagnostics. Finally, it is summarized with guidelines for in vitro diagnosis.

Exploration of inorganic nanoparticles for revolutionary drug delivery applications: a critical review

The nanosystems for delivering drugs which have evolved with time, are being designed for greater drug efficiency and lesser side-effects, and are also complemented by the advancement of numerous innovative materials. In comparison to the organic nanoparticles, the inorganic nanoparticles are stable, have a wide range of physicochemical, mechanical, magnetic, and optical characteristics, and also have the capability to get modified using some ligands to enrich their attraction towards the molecules at the target site, which makes them appealing for bio-imaging and drug delivery applications. One of the strong benefits of using the inorganic nanoparticles-drug conjugate is the possibility of delivering the drugs to the affected cells locally, thus reducing the side-effects like cytotoxicity, and facilitating a higher efficacy of the therapeutic drug. This review features the direct and indirect effects of such inorganic nanoparticles like gold, silver, graphene-based, hydroxyapatite, iron oxide, ZnO, and CeO2 nanoparticles in developing effective drug carrier systems. This article has remarked the peculiarities of these nanoparticle-based systems in pulmonary, ocular, wound healing, and antibacterial drug deliveries as well as in delivering drugs across Blood-Brain-Barrier (BBB) and acting as agents for cancer theranostics. Additionally, the article sheds light on the plausible modifications that can be carried out on the inorganic nanoparticles, from a researcher's perspective, which could open a new pathway.

Fabrication and biological investigation of a novel star polymer based on magnetic cyclic aromatic polyimide chains

Herein, a novel nanostructure based on cyclic aromatic polyimide with statistical star polymer structure was synthesized via the functionalization of the CuFe₂O₄ MNPs surface. The polymerization process on the functionalized surface of CuFe₂O₄ MNPs was performed with pyromellitic dianhydride and phenylenediamine derivatives. All analytical methods such as Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis, X-ray diffraction (XRD) pattern, energy-dispersive X-ray (EDX), field-emission scanning electron microscope (FE-SEM), vibrating-sample magnetometer (VSM) were performed to characterize the structure of CuFe₂O₄@SiO₂-polymer nanomagnetic. The cytotoxicity of CuFe₂O₄@SiO₂-Polymer was investigated for biomedical application by MTT test. The results proved that this nanocmposite was biocompatible with HEK293T healthy cells. Also, the evaluation antibacterial property of CuFe₂O₄@SiO₂-Polymer showed that its MIC in Gram-negative and Gram-positive bacteria were 500-1000 µg/mL, so it had antibacterial activity.

Implications of Crosstalk between Exosome-Mediated Ferroptosis and Diseases for Pathogenesis and Treatment

Ferroptosis is a type of iron-dependent cell death caused by ferrous iron overload, reactive oxygen species generation through the Fenton reaction, and lipid peroxidation, leading to antioxidative system dysfunction and, ultimately, cell membrane damage. The functional role of ferroptosis in human physiology and pathology is considered a cause or consequence of diseases. Circulating exosomes mediate intercellular communication and organ crosstalk. They not only transport functional proteins and nucleic acids derived from parental cells but also serve as vehicles for the targeted delivery of exogenous cargo. Exosomes regulate ferroptosis by delivering the biological material to the recipient cell, affecting ferroptosis-related proteins, or transporting ferritin-bound iron out of the cell. This review discusses pathogenesis mediated by endogenous exosomes and the therapeutic potential of exogenous exosomes for ferroptosis-related diseases. In addition, this review explores the role of exosome-mediated ferroptosis in ferroptosis-related diseases with an emphasis on strategies for engineering exosomes for ferroptosis therapy.

Fe3O4-SiO2 Mesoporous Core/Shell Nanoparticles for Magnetic Field-Induced Ibuprofen-Controlled Release

Hybrid magnetic nanoparticles made up of an iron oxide, Fe₃O₄, core and a mesoporous SiO₂ shell with high magnetization and a large surface area were proposed as an efficient drug delivery platform. The core/shell structure was synthesized by two seed-mediated growth steps combining solvothermal and sol-gel approaches and using organic molecules as a porous scaffolding template. The system presents a mean particle diameter of 30(5) nm (9 nm magnetic core diameter and 10 nm silica shell thickness) with superparamagnetic behavior, saturation magnetization of 32 emu/g, and a significant AC magnetic-field-induced heating response (SAR = 63 W/g_Fe3O4, measured at an amplitude of 400 Oe and a frequency of 307 kHz). Using ibuprofen as a model drug, the specific surface area (231 m²/g) of the porous structure exhibits a high molecule loading capacity (10 wt %), and controlled drug release efficiency (67%) can be achieved using the external AC magnetic field for short time periods (5 min), showing faster and higher drug desorption compared to that of similar stimulus-responsive iron oxide-based nanocarriers. In addition, it is demonstrated that the magnetic field-induced drug release shows higher efficiency compared to that of the sustained release at fixed temperatures (47 and 53% for 37 and 42 °C, respectively), considering that the maximum temperature reached during the exposure to the magnetic field is well below (31 °C). Therefore, it can be hypothesized that short periods of exposure to the oscillating field induce much greater heating within the nanoparticles than in the external solution.

Advanced theragnostics for the central nervous system (CNS) and neurological disorders using functional inorganic nanomaterials

Various types of inorganic nanomaterials are capable of diagnostic biomarker detection and the therapeutic delivery of a disease or inflammatory modulating agent. Those multi-functional nanomaterials have been utilized to treat neurodegenerative diseases and central nervous system (CNS) injuries in an effective and personalized manner. Even though many nanomaterials can deliver a payload and detect a biomarker of interest, only a few studies have yet to fully utilize this combined strategy to its full potential. Combining a nanomaterial's ability to facilitate targeted delivery, promote cellular proliferation and differentiation, and carry a large amount of material with various sensing approaches makes it possible to diagnose a patient selectively and sensitively while offering preventative measures or early disease-modifying strategies. By tuning the properties of an inorganic nanomaterial, the dimensionality, hydrophilicity, size, charge, shape, surface chemistry, and many other chemical and physical parameters, different types of cells in the central nervous system can be monitored, modulated, or further studies to elucidate underlying disease mechanisms. Scientists and clinicians have better understood the underlying processes of pathologies for many neurologically related diseases and injuries by implementing multi-dimensional 0D, 1D, and 2D theragnostic nanomaterials. The incorporation of nanomaterials has allowed scientists to better understand how to detect and treat these conditions at an early stage. To this end, having the multi-modal ability to both sense and treat ailments of the central nervous system can lead to favorable outcomes for patients suffering from such injuries and diseases.

Magnetic Nanoparticles for Protein Separation and Purification

Proteins are essential for various functions such as brain activity and muscle contraction in humans. Even though food is a source of proteins, the bioavailability of proteins in most foods is usually limited due to matrix interaction with other biomolecules. Thus, it is essential to extract these proteins and provide them as a nutraceutical supplement to maintain protein levels and avoid protein deficiency. Hence, protein purification and extraction from natural sources are highly significant in biomedical applications. Chromatography, crude mechanical disruption, use of extractive chemicals, and electrophoresis are some of the methods applied to isolate specific proteins. Even though these methods possess several advantages, they are unable to extract specific proteins with high purity. A suitable alternative is the use of nanoparticles, which can be beneficial in protein purification and extraction. Notably, magnetic iron and iron-based nanoparticles have been employed in protein extraction processes and can be reused via demagnetization due to their magnetic property, smaller size, morphology, high surface-to-volume ratio, and surface charge-mediated property. This chapter is a summary of various magnetic nanoparticles (MNPs) that can be used for the biomolecular separation of proteins.

Biological Applications of Silica-Based Nanoparticles

Silica nanoparticles have been widely explored in biomedical applications, mainly related to drug delivery and cancer treatment. These nanoparticles have excellent properties, high biocompatibility, chemical and thermal stability, and ease of functionalization. Moreover, silica is used to coat magnetic nanoparticles protecting against acid leaching and aggregation as well as increasing cytocompatibility. This review reports the recent advances of silica-based magnetic nanoparticles focusing on drug delivery, drug target systems, and their use in magnetohyperthermia and magnetic resonance imaging. Notwithstanding, the application in other biomedical fields is also reported and discussed. Finally, this work provides an overview of the challenges and perspectives related to the use of silica-based magnetic nanoparticles in the biomedical field.

Magnetic labeling of primary murine monocytes using very small superparamagnetic iron oxide nanoparticles

Due to their very small size, nanoparticles can interact with all cells in the central nervous system. One of the most promising nanoparticle subgroups are very small superparamagnetic iron oxide nanoparticles (VSOP) that are citrate coated for electrostatic stabilization. To determine their influence on murine blood-derived monocytes, which easily enter the injured central nervous system, we applied VSOP and carboxydextran-coated superparamagnetic iron oxide nanoparticles (Resovist). We assessed their impact on the viability, cytokine, and chemokine secretion, as well as iron uptake of murine blood-derived monocytes. We found that (1) the monocytes accumulated VSOP and Resovist, (2) this uptake seemed to be nanoparticle- and time-dependent, (3) the decrease of monocytes viability was treatment-related, (4) VSOP and Resovist incubation did not alter cytokine homeostasis, and (5) overall a 6-hour treatment with 0.75 mM VSOP-R1 was probably sufficient to effectively label monocytes for future experiments. Since homeostasis is not altered, it is safe to label blood-derived monocles with VSOP. VSOP labeled monocytes can be used to study injured central nervous system sites further, for example with drug-carrying VSOP.

Ultrasmall Superparamagnetic Iron Oxide Nanoparticles as Nanocarriers for Magnetic Resonance Imaging: Development and In Vivo Characterization

Ultrasmall superparamagnetic iron oxide nanoparticles (uSPIOs) are attractive platforms for the development of smart contrast agents for magnetic resonance imaging (MRI). Oleic acid-capped uSPIOs are commercially available yet hydrophobic, hindering in vivo applications. A hydrophilic ligand with high affinity toward uSPIO surfaces can render uSPIOs water-soluble, biocompatible, and highly stable under physiological conditions. A small overall hydrodynamic diameter ensures optimal pharmacokinetics, tumor delivery profiles, and, of particular interest, enhanced T ₁ MR contrasts. In this study, for the first time, we synthesized a ligand that not only fulfills the as-proposed properties but also provides multiple reactive groups for further modifications. The synthesis delivers a facile approach using commercially available reactants, with resultant uSPIO-ligand constructs assembled through a single-step ligand exchange process. Structural and molecular size analyses confirmed size uniformity and small hydrodynamic diameter of the constructs. On average, 43 reactive amine groups were present per uSPIO nanoparticle. Its r ₁ relaxivity has been tested on a 7 Tesla MR instrument and is comparable to that of the clinically available T ₁ gadolinium-based contrast agent GBCA (1 vs 3 mM^-1 s^-1, respectively). A significant decrease in tumor T1 (15%) within 1 h of injection and complete signal recovery after 2 h were detected with a dose of 7 μg Fe/g mouse. The agent also has high r ₂ relaxivity and can be used for T ₂ contrast-enhanced MRI. Taken together, good relaxation and delivery properties and the presence of multiple surface reactive groups can facilitate its application as a universal MRI-compatible nanocarrier platform.

Magnetic nanoparticles and magnetic particle spectroscopy-based bioassays: a 15 year recap

Magnetic nanoparticles (MNPs) have unique physical and chemical properties, such as high surface area to volume ratio and size-related magnetism, which are completely different from their bulk materials. Benefiting from the facile synthesis and chemical modification strategies, MNPs have been widely studied for applications in nanomedicine. Herein, we firstly summarized the designs of MNPs from the perspectives of materials and physicochemical properties tailored for biomedical applications. Magnetic particle spectroscopy (MPS), first reported in 2006, has flourished as an independent platform for many biological and biomedical applications. It has been extensively reported as a versatile platform for a variety of bioassays along with the artificially designed MNPs, where the MNPs serve as magnetic nanoprobes to specifically probe target analytes from fluid samples. In this review, the mechanisms and theories of different MPS platforms realizing volumetric- and surface-based bioassays are discussed. Some representative works of MPS platforms for applications such as disease diagnosis, food safety and plant pathology monitoring, drug screening, thrombus maturity assessments are reviewed. At the end of this review, we commented on the rapid growth and booming of MPS-based bioassays in its first 15 years. We also prospected opportunities and challenges that portable MPS devices face in the rapidly growing demand for fast, inexpensive, and easy-to-use biometric techniques.

Using small-angle scattering to guide functional magnetic nanoparticle design

Magnetic nanoparticles offer unique potential for various technological, biomedical, or environmental applications thanks to the size-, shape- and material-dependent tunability of their magnetic properties. To optimize particles for a specific application, it is crucial to interrelate their performance with their structural and magnetic properties. This review presents the advantages of small-angle X-ray and neutron scattering techniques for achieving a detailed multiscale characterization of magnetic nanoparticles and their ensembles in a mesoscopic size range from 1 to a few hundred nanometers with nanometer resolution. Both X-rays and neutrons allow the ensemble-averaged determination of structural properties, such as particle morphology or particle arrangement in multilayers and 3D assemblies. Additionally, the magnetic scattering contributions enable retrieving the internal magnetization profile of the nanoparticles as well as the inter-particle moment correlations caused by interactions within dense assemblies. Most measurements are used to determine the time-averaged ensemble properties, in addition advanced small-angle scattering techniques exist that allow accessing particle and spin dynamics on various timescales. In this review, we focus on conventional small-angle X-ray and neutron scattering (SAXS and SANS), X-ray and neutron reflectometry, gracing-incidence SAXS and SANS, X-ray resonant magnetic scattering, and neutron spin-echo spectroscopy techniques. For each technique, we provide a general overview, present the latest scientific results, and discuss its strengths as well as sample requirements. Finally, we give our perspectives on how future small-angle scattering experiments, especially in combination with micromagnetic simulations, could help to optimize the performance of magnetic nanoparticles for specific applications.

Advances in antitumor nanomedicine based on functional metal-organic frameworks beyond drug carriers

Nanoscale metal-organic frameworks (MOFs) have attracted widespread interest due to their unique properties including a tunable porous structure, high drug loading capacity, structural diversity, and outstanding biocompatibility. MOFs have been extensively explored as drug nanocarriers in biotherapeutics. However, by harnessing the functionality of ligands and metal ions or clusters in MOFs, the applications of MOFs can be extended beyond drug delivery vehicles. Based on the intrinsic properties of the components of MOFs (e.g. magnetic moments of metal ions and fluorescence of ligands), different imaging modes can be achieved with varied MOFs. With careful design of the composition of MOFs (e.g. modification of organic linkers), they can respond to tumor microenvironments to realize on-demand treatment. By incorporating porphyrin-based ligands (photosensitizers for photodynamic therapy) or high-Z metal ions (radiosensitizers for radiotherapy) into the scaffold of MOFs, MOFs themselves can act as anticancer therapeutic agents. In this review, we highlight the application of MOFs from the above-mentioned aspects and discuss the prospects and challenges for using MOFs in stimuli-responsive imaging-guided antitumor therapy.

Combustion-assisted green-synthesized magnesium-doped cadmium ferrite nanoparticles for multifunctional applications

Magnesium-doped cadmium ferrite nanoparticles, MgXCd1−XFe2O4 (where, X = 0, 0.2, 0.4, 0.6, 0.8, 1) were synthesized by a combustion method using curd as fuel.

Self-Adaptive Acceptance Rate-Driven Markov Chain Monte Carlo Method Applied to the Study of Magnetic Nanoparticles

A standard canonical Markov Chain Monte Carlo method implemented with a single-macrospin movement Metropolis dynamics was conducted to study the hysteretic properties of an ensemble of independent and non-interacting magnetic nanoparticles with uniaxial magneto-crystalline anisotropy randomly distributed. In our model, the acceptance-rate algorithm allows accepting new updates at a constant rate by means of a self-adaptive mechanism of the amplitude of Néel rotation of magnetic moments. The influence of this proposal upon the magnetic properties of our system is explored by analyzing the behavior of the magnetization versus field isotherms for a wide range of acceptance rates. Our results allows reproduction of the occurrence of both blocked and superparamagnetic states for high and low acceptance-rate values respectively, from which a link with the measurement time is inferred. Finally, the interplay between acceptance rate with temperature in hysteresis curves and the time evolution of the saturation processes is also presented and discussed.

Applications of nanomagnets as dynamical systems: I

When magnets are fashioned into nanoscale elements, they exhibit a wide variety of phenomena replete with rich physics and the lure of tantalizing applications. In this topical review, we discuss some of these phenomena, especially those that have come to light recently, and highlight their potential applications. We emphasize what drives a phenomenon, what undergirds the dynamics of the system that exhibits the phenomenon, how the dynamics can be manipulated, and what specific features can be harnessed for technological advances. For the sake of balance, we point out both advantages and shortcomings of nanomagnet based devices and systems predicated on the phenomena we discuss. Where possible, we chart out paths for future investigations that can shed new light on an intriguing phenomenon and/or facilitate both traditional and non-traditional applications.

Therapeutic Potential and Main Methods of Obtaining Selenium Nanoparticles

This review presents the latest data on the importance of selenium nanoparticles in human health, their use in medicine, and the main known methods of their production by various methods. In recent years, a multifaceted study of nanoscale complexes in medicine, including selenium nanoparticles, has become very important in view of a number of positive features that make it possible to create new drugs based on them or significantly improve the properties of existing drugs. It is known that selenium is an essential trace element that is part of key antioxidant enzymes. In mammals, there are 25 selenoproteins, in which selenium is a key component of the active site. The important role of selenium in human health has been repeatedly proven by several hundred works in the past few decades; in recent years, the study of selenium nanocomplexes has become the focus of researchers. A large amount of accumulated data requires generalization and systematization in order to improve understanding of the key mechanisms and prospects for the use of selenium nanoparticles in medicine, which is the purpose of this review.

Adsorption of Organic Dyes on Magnetic Iron Oxide Nanoparticles. Part II: Field-Induced Nanoparticle Agglomeration and Magnetic Separation

This paper (part II) is devoted to the effect of molecular adsorption on the surface of magnetic iron oxide nanoparticles (IONP) on the enhancement of their (secondary) field-induced agglomeration and magnetic separation. Experimentally, we use Methylene Blue (MB) cationic dye adsorption on citrate-coated maghemite nanoparticles to provoke primary agglomeration of IONP in the absence of the field. The secondary agglomeration is manifested through the appearance of needlelike micron-sized agglomerates in the presence of an applied magnetic field. With the increasing amount of adsorbed MB molecules, the size of the field-induced agglomerates increases and the magnetic separation on a magnetized micropillar becomes more efficient. These effects are mainly governed by the ratio of magnetic-to-thermal energy α, suspension supersaturation Δ₀, and Brownian diffusivity D_eff of primary agglomerates. The three parameters (α, Δ₀, and D_eff) are implicitly related to the surface coverage θ of IONP by MB molecules through the hydrodynamic size of primary agglomerates exponentially increasing with θ. Experiments and developed theoretical models allow quantitative evaluation of the θ effect on the efficiency of the secondary agglomeration and magnetic separation.

Atomic Resolution Electron Microscopy: A Key Tool for Understanding the Activity of Nano-Oxides for Biomedical Applications

Transition metal oxides constitute one of the most fruitful sources of materials with continuously increasing potential applications prompted by the expectations derived from the reduction of the particle size. The recent advances in transmission electron microscopy, because of the development of lenses, have made it possible to reach atomic resolution, which can provide answers regarding the performance of the transition metal nano-oxides. This critical information is related not only to the ability to study their microstructural characteristics but also their local composition and the oxidation state of the transition metal. Exploring these features is a well-known task in nano-oxides for energy and electronic technologies, but they are not so commonly used for elucidating the activity of these oxides for biomedical applications. Nevertheless, the identification at the atomic level of a certain dopant or the unambiguous determination of the oxidation state of a transition metal in a nano-oxide can be important questions to be answered in a certain biomedical application. In this work, we provide several examples in transition metal nano-oxides to show how atomic-resolution electron microscopy can be a key tool for its understanding.

Comparative Study of Specific Loss Power and Transverse Relaxivity of Spinel Ferrite Nanoensembles Coated With Chitosan and Polyethylene Glycol

We synthesized spinel ferrite nanoensembles (MnFe2O4, CoFe2O4, and Fe3O4) using the chemical co-precipitation method and characterized their physical, chemical, and magnetic properties by X-ray diffraction (XRD), transmission electron microscopy (TEM), physical properties measurement system (PPMS), Mössbauer spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and Raman spectroscopy. Their relaxation properties and potential for hyperthermia therapy were determined using nuclear magnetic resonance (NMR) and cell viability assay, respectively. XRD and TEM data confirmed that the particle core sizes were 6–9 nm before coating while their sizes increased to 10–14 nm and 14–20 nm after coating with chitosan and polyethylene glycol (PEG), respectively. Mössbauer spectroscopy showed superparamagnetic behavior for MnFe2O4 nanoparticles and ferrimagnetic behavior for the CoFe2O4 and Fe3O4 nanoparticles. A detailed studies of MH loops of all three ferrites before and after coating showed surface functionalization by a large reduction of coercivity and anisotropy. The successful coating was further confirmed by the peak shifts in the FTIR spectra of the particles whereas Raman spectra of coated ferrites also displayed the characteristic absorption patterns and suppression of the ferrite peaks suggesting successful coating. The induced heating profile of the nanoparticles in stable suspension was tested with a radio frequency magnetic field of 76 mT and a frequency of 400 kHz. High mortality (>98%) of 9 L gliosarcoma cancer cells by hyperthermia suggested that these nanoparticles could be used for cancer therapy. Transverse relaxivities (r2) determined by NMR for chitosan-coated MnFe2O4, CoFe2O4, and Fe3O4 nanoparticles were 297 (±22), 353 (±26), and 345 (±13), mM−1S−1, while for PEG-coated nanoparticles are 165 (±22), 146 (±14), and 159 (±07) mM−1S−1, respectively. Overall these spinel ferrite nanoensembles show great promise for cancer theranostics research applications.

Polyethylene Glycol Coated Magnetic Nanoparticles: Hybrid Nanofluid Formulation, Properties and Drug Delivery Prospects

Magnetic nanoparticles (MNPs) are widely used materials for biomedical applications owing to their intriguing chemical, biological and magnetic properties. The evolution of MNP based biomedical applications (such as hyperthermia treatment and drug delivery) could be advanced using magnetic nanofluids (MNFs) designed with a biocompatible surface coating strategy. This study presents the first report on the drug loading/release capability of MNF formulated with methoxy polyethylene glycol (referred to as PEG) coated MNP in aqueous (phosphate buffer) fluid. We have selected MNPs (NiFe₂O4, CoFe₂O4 and Fe₃O₄) coated with PEG for MNF formulation and evaluated the loading/release efficacy of doxorubicin (DOX), an anticancer drug. We have presented in detail the drug loading capacity and the time-dependent cumulative drug release of DOX from PEG-coated MNPs based MNFs. Specifically, we have selected three different MNPs (NiFe₂O₄, CoFe₂O₄ and Fe₃O₄) coated with PEG for the MNFs and compared their variance in the loading/release efficacy of DOX, through experimental results fitting into mathematical models. DOX loading takes the order in the MNFs as CoFe₂O₄ > NiFe₂O₄ > Fe₃O₄. Various drug release models were suggested and evaluated for the individual MNP based NFs. While the non-Fickian diffusion (anomalous) model fits for DOX release from PEG coated CoFe₂O₄, PEG coated NiFe₂O₄ NF follows zero-order kinetics with a slow drug release rate of 1.33% of DOX per minute. On the other hand, PEG coated NiFe₂O₄ follows zero-order DOX release. Besides, several thermophysical properties and magnetic susceptibility of the MNFs of different concentrations have been studied by dispersing the MNPs (NiFe₂O₄, CoFe₂O₄ and Fe₃O₄) in the base fluid at 300 K under ultrasonication. This report on the DOX loading/release capability of MNF will set a new paradigm in view that MNF can resolve problems related to the self-heating of drug carriers during mild laser treatment with its thermal conducting properties.

Ultrasound-induced and MRI-monitored CuO nanoparticles release from micelle encapsulation

Copper oxide nanoparticles (CuO NPs) have anticancer and antimicrobial activities. Moreover, they have a contrast enhancing effect in both MRI and ultrasound. Nonetheless, encapsulation is needed to control their toxic side effects and a mechanism for release on demand is required. A methodology is introduced herein for encapsulating and releasing CuO NPs from micelles by ultrasound induced hyperthermia and monitoring the process by MRI. For this aim, CuO NPs loaded poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-b-PLA) micelles were prepared. Then, the profile of copper release with application of ultrasound was examined as a function of time and temperature using a colorimetric method. Finally, T1 weighted MRI images of suspensions and ex vivo poultry liver samples containing the CuO NPs loaded micelles were acquired before and after ultrasound application. The results confirmed that: (i) encapsulated NPs are detectible by MRI T1 mapping, depicting substantial T1 shortening from 1872 ± 62 ms to 683 ± 20 ms. (ii) Ultrasonic hyperthermia stimulated the NPs release with an about threefold increase compared to non-treated samples. (iii) Releasing effect was clearly visible by T1-weighted imaging (mean signal increase ratio of 2.29). These findings can potentially lead to the development of a new noninvasive methodology for CuO NPs based theranostic process.

Cardiac MRI Assessment of Mouse Myocardial Infarction and Regeneration

Small animal models are indispensable for cardiac regeneration research. Studies in mouse and rat models have provided important insights into the etiology and mechanisms of cardiovascular diseases and accelerated the development of therapeutic strategies. It is vitally important to be able to evaluate the therapeutic efficacy and have reliable surrogate markers for therapeutic development for cardiac regeneration research. Magnetic resonance imaging (MRI), a versatile and noninvasive imaging modality with excellent penetration depth, tissue coverage, and soft-tissue contrast, is becoming a more important tool in both clinical settings and research arenas. Cardiac MRI (CMR) is versatile, noninvasive, and capable of measuring many different aspects of cardiac functions, and, thus, is ideally suited to evaluate therapeutic efficacy for cardiac regeneration. CMR applications include assessment of cardiac anatomy, regional wall motion, myocardial perfusion, myocardial viability, cardiac function assessment, assessment of myocardial infarction, and myocardial injury. Myocardial infarction models in mice are commonly used model systems for cardiac regeneration research. In this chapter, we discuss various CMR applications to evaluate cardiac functions and inflammation after myocardial infarction.

Tomographic Field Free Line Magnetic Particle Imaging With an Open-Sided Scanner Configuration

Superparamagnetic iron oxide nanoparticles (SPIONs) have a high potential for use in clinical diagnostic and therapeutic applications. In vivo distribution of SPIONs can be imaged with the Magnetic Particle Imaging (MPI) method, which uses an inhomogeneous magnetic field with a field free region (FFR). The spatial distribution of the SPIONs are obtained by scanning the FFR inside the field of view (FOV) and sensing SPION related magnetic field disturbance. MPI magnets can be configured to generate a field free point (FFP), or a field free line (FFL) to scan the FOV. FFL scanners provide more sensitivity, and are also more suitable for scanning large regions compared to FFP scanners. Interventional procedures will benefit greatly from FFL based open magnet configurations. Here, we present the first open-sided MPI system that can electronically scan the FOV with an FFL to generate tomographic MPI images. Magnetic field measurements show that FFL can be rotated electronically in the horizontal plane and translated in three dimensions to generate 3D MPI images. Using the developed scanner, we obtained 2D images of dot and cylinder phantoms with varying iron concentrations between 11 [Formula: see text]/ml and 770 [Formula: see text]/ml. We used a measurement based system matrix image reconstruction method that minimizes l₁ -norm and total variation in the images. Furthermore, we present 2D imaging results of two 4 mm-diameter vessel phantoms with 0% and 75% stenosis. The experiments show high quality imaging results with a resolution down to 2.5 mm for a relatively low gradient field of 0.6 T/m.

Nondestructive Chemical Analysis of the Iron-Containing Protein Ferritin Using Raman Microspectroscopy

Ferritin is a ubiquitous intracellular iron storage protein of animals, plants, and bacteria. The cavity of this protein acts like a reaction chamber for natural formation and storage of nano-sized particles via biomineralization. Knowledge of the chemical composition and structure of the iron core is highly warranted in the fields of nano technologies as well as biomolecules and medicine. Here, we show that Raman microspectroscopy (RM) is a suitable nondestructive approach for an analysis of proteins containing such nano-sized iron oxides. Our approach addresses: (1) synthesis of suitable reference materials, i.e., ferrihydrite, maghemite and magnetite nanoparticles; (2) optimization of parameters for Raman spectroscopic analysis; (3) comparison of Raman spectra from ferritin with apoferritin and our reference minerals; and (4) validation of Raman analysis by X-ray diffraction and Mössbauer spectroscopy as two independent complementary approaches. Our results reveal that the iron core of natural ferritin is composed of the iron(III) hydroxide ferrihydrite (Fe₂O₃ ∙ 0.5 H₂O).

Effect of superparamagnetic iron oxide nanoparticles on glucose homeostasis on type 2 diabetes experimental model

AIMS

Evaluation of the anti-diabetic effect of superparamagnetic iron oxide nanoparticles (SPIONs) on Type 2 diabetic rats and compared their effect to metformin treatment.

MAIN METHODS

Diabetic rats were treated with different doses of nanoparticles one time per week for 4 weeks. Fasting blood glucose level was determined for studied groups during the experimental period (30 days). At the end of the experiment, oral glucose tolerance test was carried out, serum samples were collected for biochemical assays. Then animals were sacrificed to obtain tissues for assessment of glucose transporters, insulin receptors and insulin signaling proteins.

KEY FINDING

SPIONs treatment normalized fasting blood glucose and lowering insulin level in diabetic rats compared to untreated diabetic rats. SPIONs significantly ameliorate the glucose sensing and the active components of insulin signaling pathway. The anti-diabetic effects of SPIONs may be mediated through its effect on (i) hepatic peroxisome proliferator-activated receptor gamma coactivator 1-alpha content, which induced by SPIONs treatment in a dose-dependent manner, (ii) adipocytokines as SPIONs treated diabetic rats showed significantly higher levels of adiponectin and lower retinol binding protein 4 compared to untreated diabetic rats, (iii) lipid profile as SPIONs treatment significantly corrected the lipid profile in a dose-dependent manner and to a similar extent as metformin or even better.

SIGNIFICANCE

To our knowledge, this is the first study that explores the anti-diabetic effects of SPIONs on diabetic model.

99mTc-, 90Y-, and 177Lu-Labeled Iron Oxide Nanoflowers Designed for Potential Use in Dual Magnetic Hyperthermia/Radionuclide Cancer Therapy and Diagnosis

Development of a complex based on iron oxide nanoparticles (IONPs) for diagnosis and dual magnetic hyperthermia/radionuclide cancer therapy accomplishing high yields of radiolabeling and great magnetic heat induction is still a challenge. We report here the synthesis of citric acid, poly(acrylic acid) (PAA) and poly(ethylene glycol) coated IONPs and their labeling with three radionuclides, namely, technetium (^99mTc), yttrium (⁹⁰Y), and lutetium (¹⁷⁷Lu), aiming at potential use in cancer diagnosis and therapy. Polyol-synthesized IONPs are a flowerlike structure with 13.5 nm spherically shaped cores and 24.8 nm diameter. PAA-coated nanoparticles (PAA@IONP) showed the best characteristics such as easy radiolabeling with very high yields (>97.5%) with all three radionuclides, and excellent in vitro stabilities with less than 10% of radionuclides detaching after 24 h. Heating ability of PAA@IONP in an alternating external magnetic field showed intrinsic loss power value of 7.3 nH m²/kg, which is one of higher reported values. Additionally, PAA@IONP itself presented no significant cytotoxicity to the CT-26 cancer cells, reaching IC50 at 60 μg/mL. However, under the external magnetic field, they show hyperthermia-mediated cells killing, which correlated with the magnetic field strength and time of exposure. Since PAA@IONP are easy to prepare, biocompatible, and with excellent magnetic heat induction, these nanoparticles radiolabeled with high-energy beta emitters ⁹⁰Y and ¹⁷⁷Lu have valuable potential as agent for dual magnetic hyperthermia/radionuclide therapy, while radiolabeled with ^99mTc could be used in diagnostic imaging.

Present and future of siderophore-based therapeutic and diagnostic approaches in infectious diseases

Iron is an essential micronutrient required for the growth of almost all aerobic organisms; the iron uptake pathway in bacteria therefore represents a possible target for novel antimicrobials, including hybrids between antimicrobials and siderophores. Siderophores are low molecular weight iron chelators that bind to iron and are actively transported inside the cell through specific binding protein complexes. These binding protein complexes are present both in Gram negative bacteria, in their outer and inner membrane, and in Gram positive bacteria in their cytoplasmic membrane. Most bacteria have the ability to produce siderophores in order to survive in environments with limited concentrations of free iron, however some bacteria synthetize natural siderophore-antibiotic conjugates that exploit the siderophore-iron uptake pathway to deliver antibiotics into competing bacterial cells and gain a competitive advantage. This approach has been referred to as a Trojan Horse Strategy. To overcome the increasing global problem of antibiotic resistance in Gram negative bacteria, which often have reduced outer membrane permeability, siderophore-antibiotic hybrid conjugates have been synthetized in vitro. Cefiderocol is the first siderophore-antibiotic conjugate that progressed to late stage clinical development so far. In studies on murine models the iron-siderophore uptake pathway has been also exploited for diagnostic imaging of infectious diseases, in which labelled siderophores have been used as specific probes. The aim of this review is to describe the research progress in the field of siderophore-based therapeutic and diagnostic approaches in infectious diseases.

Biochemical functionality of magnetic particles as nanosensors: how far away are we to implement them into clinical practice?

Magnetic nanosensors have become attractive instruments for the diagnosis and treatment of different diseases. They represent an efficient carrier system in drug delivery or in transporting contrast agents. For such purposes, magnetic nanosensors are used in vivo (intracorporeal application). To remove specific compounds from blood, magnetic nanosensors act as elimination system, which represents an extracorporeal approach. This review discusses principles, advantages and risks on recent advances in the field of magnetic nanosensors. First, synthesis methods for magnetic nanosensors and possibilities for enhancement of biocompatibility with different coating materials are addressed. Then, attention is devoted to clinical applications, in which nanosensors are or may be used as carrier- and elimination systems in the near future. Finally, risk considerations and possible effects of nanomaterials are discussed when working towards clinical applications with magnetic nanosensors.

Externally Controlled Cellular Transport of Magnetic Iron Oxide Particles with Polysaccharide Surface Coatings

Recently, due to their promising applications in biomedicine, magnetic iron oxide nanoparticles (MPs) have become one of the research hotspots in the nanomedicine field. Since various synthetic modifications have been widely applied to these nanoparticles for better targeting behaviors, it is meaningful to apply the optimal magnetic field condition for each case. This will enable creating a safe and efficient drug targeting using different types of MPs. In the present study, we aimed to find out any changes of transepithelial transport of polysaccharide-coated MPs by applying the continuous or the pulsatile magnetic field condition. Our results with heparin-functionalized MPs indicate that the particle concentrations and the external magnetic field could influence the transepithelial permeability of the particles. In the presence of a continuously applied magnetic density, heparin-MPs at high concentrations, by forming magnetically-induced aggregation of particles over the cell surface layer, showed a lower cellular transport than those at low concentrations. Furthermore, the results from the quantitative chemical assays and imaging analyses showed that transepithelial transport of heparin-MPs (negatively charged) under the pulsatile magnetic field was higher than that under the continuous magnetic field (CP), whereas the starch-MPs (neutrally charged) showed a small difference in transepithelial transport or cell retention between pulsatile vs. continuous magnetic field conditions. Taken together, our results suggest that the external magnetic field should be differentially applied to control the cellular drug transport depending on the physicochemical properties of the surface chemistry of magnetic particles.

Clustering superparamagnetic iron oxide nanoparticles produces organ-targeted high-contrast magnetic resonance images

Aim: Superparamagnetic iron oxide nanoparticles (SPIONs) have been used as magnetic resonance imaging (MRI) contrast agents; however, a number of T2-weighted imaging SPIONs have been withdrawn due to their poor clinical contrast performance. Our aim was to significantly improve SPION T2-weighted MRI contrast by clustering SPIONs within novel chitosan amphiphiles. Methods: Clustering SPIONs was achieved by encapsulation of hydrophobic-coated SPIONs with an amphiphilic chitosan polymer (GCPQ). Results: Clustering increases the spin-spin (r₂) to spin-lattice (r₁) relaxation ratio (r₂/r₁) from 3.0 to 79.1, resulting in superior contrast. Intravenously administered clustered SPIONs accumulated only in the liver and spleen; with the reduction in T2 relaxation confined, in the liver, to the extravascular space, giving clear MRI images of the liver vasculature.

Early diagnosis of cerebral thrombosis by EGFP–EGF1 protein conjugated ferroferric oxide magnetic nanoparticles

Cerebral thrombosis disease is a worldwide problem, with high rates of morbidity, disability, and mortality. Magnetic resonance imaging diffusion-weighted imaging was used as an important early diagnostic method for cerebral thrombotic diseases; however, its diagnosis time is 2 h after onset. In this study, we designed EGFP–EGF1–NP–Fe3O4 for earlier diagnosis of cerebral thrombosis by taking advantage of EGFP–EGF1 fusion protein, in which EGF1 can bind with tissue factor and enhanced green fluorescent protein has previously been widely used as a fluorescent protein marker. EGFP–EGF1–NP–Fe3O4 or NP–Fe3O4 reaches the highest concentration in the infarction areas in 1 h. To evaluate the targeting ability of EGFP–EGF1–NP–Fe3O4, a fluorochrome dye, Dir, was loaded into the nanoparticle. As shown by the in vivo organ multispectral fluorescence imaging, Dir-loaded EGFP–EGF1–NP–Fe3O4 exhibited higher fluorescence than those of model rats treated with Dir-loaded NP–Fe3O4. Coronal frozen sections and transmission electron microscope further showed that EGFP–EGF1–NP–Fe3O4 was mainly accumulated in the tissue factor exposure region of brain. The data indicated that the EGFP–EGF1–NP–Fe3O4 targeted cerebral thrombosis and might be applied in the early diagnosis of intracranial thrombosis.

Cobalt ferrite supported on reduced graphene oxide as a T2 contrast agent for magnetic resonance imaging

Nanoscaled spinel-structured ferrites bear promise as next-generation contrast agents for magnetic resonance imaging. However, the small size of the particles commonly leads to colloidal instability under physiological conditions. To circumvent this problem, supports onto which the dispersed nanoparticles can be anchored have been proposed. Amongst these, flakes of graphene have shown interesting performance but it remains unknown if and how their surface texture and chemistry affect the magnetic properties and relaxation time (T₂) of the ferrite nanoparticles. Here, it is shown that the type of graphene oxide (GO) precursor, used to make composites of cobalt ferrite (CoFe₂O₄) and reduced GO, influences greatly not just the T₂ but also the average size, dispersion and magnetic behaviour of the grafted nanoparticles. Accordingly, and without compromising biocompatibility, a judicious choice of the initial GO precursor can result in the doubling of the proton relaxivity rate in this system.

In a one-pot hydrothermal synthesis of MRI-active CoFe₂O₄ nanoparticles grafted onto graphene flakes, careful selection of the parent graphene oxide enables major increments in grafting yield and proton relaxivity rates.

Cancer Immunotherapy of TLR4 Agonist-Antigen Constructs Enhanced with Pathogen-Mimicking Magnetite Nanoparticles and Checkpoint Blockade of PD-L1

Despite the tremendous potential of Toll-like receptor 4 (TLR4) agonists in vaccines, their efficacy as monotherapy to treat cancer has been limited. Only some lipopolysaccharides (LPS) isolated from particular bacterial strains or structures like monophosphoryl lipid A (MPLA) derived from lipooligosaccharide (LOS), avoid toxic overactivation of innate immune responses while retaining adequate immunogenicity to act as adjuvants. Here, different LOS structures are incorporated into nanoparticle-filled phospholipid micelles for efficient vaccine delivery and more potent cancer immunotherapy. The structurally unique LOS of the plant pathogen Xcc is incorporated into phospholipid micelles encapsulating iron oxide nanoparticles, producing stable pathogen-mimicking nanostructures suitable for targeting antigen presenting cells in the lymph nodes. The antigen is conjugated via a hydrazone bond, enabling rapid, easy-to-monitor and high-yield antigen ligation at low concentrations. The protective effect of these constructs is investigated against a highly aggressive model for tumor immunotherapy. The results show that the nanovaccines lead to a higher-level antigen-specific cytotoxic T lymphocyte (CTL) effector and memory responses, which when combined with abrogation of the immunosuppressive programmed death-ligand 1 (PD-L1), provide 100% long-term protection against repeated tumor challenge. This nanovaccine platform in combination with checkpoint inhibition of PD-L1 represents a promising approach to improve the cancer immunotherapy of TLR4 agonists.

Iron Oxide Nanoparticles for Biomedical Applications: A Perspective on Synthesis, Drugs, Antimicrobial Activity, and Toxicity

Medical applications and biotechnological advances, including magnetic resonance imaging, cell separation and detection, tissue repair, magnetic hyperthermia and drug delivery, have strongly benefited from employing iron oxide nanoparticles (IONPs) due to their remarkable properties, such as superparamagnetism, size and possibility of receiving a biocompatible coating. Ongoing research efforts focus on reducing drug concentration, toxicity, and other side effects, while increasing efficacy of IONPs-based treatments. This review highlights the methods of synthesis and presents the most recent reports in the literature regarding advances in drug delivery using IONPs-based systems, as well as their antimicrobial activity against different microorganisms. Furthermore, the toxicity of IONPs alone and constituting nanosystems is also addressed.

Design and preparation of bi-functionalized short-chain modified zwitterionic nanoparticles

An ideal nanomaterial for use in the bio-medical field should have a distinctive surface capable of effectively preventing nonspecific protein adsorption and identifying target bio-molecules. Recently, the short-chain zwitterion strategy has been suggested as a simple and novel approach to create outstanding anti-fouling surfaces. In this paper, the carboxyl end group of short-chain zwitterion-coated silica nanoparticles (SiO₂-ZWS) was found to be difficult to functionalize via a conventional EDC/NHS strategy due to its rapid hydrolysis side-reactions. Hence, a series of bi-functionalized silica nanoparticles (SiO₂-ZWS/COOH) were designed and prepared by controlling the molar ratio of 3-aminopropyltriethoxysilane (APTES) to short-chain zwitterionic organosiloxane (ZWS) in order to achieve above goal. The synthesized SiO₂-ZWS/COOH had similar excellent anti-fouling properties compared with SiO₂-ZWS, even in 50% fetal bovine serum characterized by DLS and turbidimetric titration. Subsequently, SiO₂-ZWS/COOH_5/1 was chosen as a representative and then demonstrated higher detection signal intensity and more superior signal-to-noise ratios compare with the pure SiO₂-COOH when they were used as a bio-carrier for chemiluminescence enzyme immunoassay (CLEIA). These unique bi-functionalized silica nanoparticles have many potential applications in the diagnostic and therapeutic fields.

STATEMENT OF SIGNIFICANCE

Reducing nonspecific protein adsorption and enhancing the immobilized efficiency of specific bio-probes are two of the most important issues for bio-carriers, particularly for a nanoparticle based bio-carrier. Herein, we designed and prepared a bi-functional nanoparticle with anti-fouling property and bio conjugation capacity for further bioassay by improving the short-chain zwitterionic modification strategy we have proposed previously. The heterogeneous surface of this nanoparticle showed effective anti-fouling properties both in model protein solutions and fetal bovine serum (FBS). The modified nanoparticles can also be successfully functionalized with a specific antibody for CLEIA assay with a prominent bio-detection performance even in 50% FBS. In this paper, we also investigated an unexpectedly fast hydrolysis behavior of NHS-activated carboxylic groups within the pure short-chain zwitterionic molecule that led to no protein binding in the short-chain zwitterion modified nanoparticle. Our findings pave a new way for the designing of high performance bio-carriers, demonstrating their strong potential as a robust platform for diagnosis and therapy.

Multi-scale X-ray computed tomography to detect and localize metal-based nanomaterials in lung tissues of in vivo exposed mice

In this methodological study, we demonstrated the relevance of 3D imaging performed at various scales for the ex vivo detection and location of cerium oxide nanomaterials (CeO₂-NMs) in mouse lung. X-ray micro-computed tomography (micro-CT) with a voxel size from 14 µm to 1 µm (micro-CT) was combined with X-ray nano-computed tomography with a voxel size of 63 nm (nano-CT). An optimized protocol was proposed to facilitate the sample preparation, to minimize the experimental artifacts and to optimize the contrast of soft tissues exposed to metal-based nanomaterials (NMs). 3D imaging of the NMs biodistribution in lung tissues was consolidated by combining a vast variety of techniques in a correlative approach: histological observations, 2D chemical mapping and speciation analysis were performed for an unambiguous detection of NMs. This original methodological approach was developed following a worst-case scenario of exposure, i.e. high dose of exposure with administration via intra-tracheal instillation. Results highlighted both (i) the non-uniform distribution of CeO₂-NMs within the entire lung lobe (using large field-of-view micro-CT) and (ii) the detection of CeO₂-NMs down to the individual cell scale, e.g. macrophage scale (using nano-CT with a voxel size of 63 nm).

Magnetic Nanoparticles Interact and Pass an In Vitro Co-Culture Blood-Placenta Barrier Model

Magnetic nanoparticles are interesting tools for biomedicine. Before application, critical prerequisites have to be fulfilled. An important issue is the contact and interaction with biological barriers such as the blood-placenta barrier. In order to study these processes in detail, suitable in vitro models are needed. For that purpose a blood-placenta barrier model based on the trophoblast-like cell line BeWo and primary placenta-derived pericytes was established. This model was characterized by molecular permeability, transepithelial electrical resistance and cell-cell-contact markers. Superparamagnetic iron oxide nanoparticles (SPIONs) with cationic, anionic or neutral surface charge were applied. The localization of the nanoparticles within the cells was illustrated by histochemistry. The time-dependent passage of the nanoparticles through the BeWo/pericyte barrier was measured by magnetic particle spectroscopy and atomic absorption spectroscopy. Cationically coated SPIONs exhibited the most extensive interaction with the BeWo cells and remained primarily in the BeWo/pericyte cell layer. In contrast, SPIONs with neutral and anionic surface charge were able to pass the cell layer to a higher extent and could be detected beyond the barrier after 24 h. This study showed that the mode of SPION interaction with and passage through the in vitro blood-placenta barrier model depends on the surface charge and the duration of treatment.

Propylamine-containing magnetic ethyl-based organosilica with a core–shell structure: an efficient and highly stable nanocatalyst

A novel propylamine-containing magnetic organosilica is prepared and characterized, and its catalytic performance is investigated in the Knoevenagel reaction.

Recurrent exposure to ferric oxide nanoparticles alters myocardial oxidative stress, apoptosis and necrotic markers in male mice

The cardiotoxicity of iron oxide nanoparticles (Fe₂O₃-NPs) in mice was investigated. The mice were intraperitoneally administered with Fe₂O₃-NPs at the dose of 25 and 50 mg/kg bw for 30 days at seven days interval. In vivo MRI analysis reveals the Fe₂O₃-NPs accumulation in the cardiac system. Also, serum iron estimation and Prussian blue staining confirms the iron deposition in circulatory system. Cardiac dysfunction was assessed by ECG analysis and further validated by evaluating the functional markers such as cardiac Troponin-1 (cTnI) expression, AChE activity and levels of LDH and CK-MB in cardiac tissue. Fe₂O₃-NPs exposure disturbs the balance between the oxidants and antioxidants resulting in oxidative myocardial damages. In consequence, damaged mitochondria, diminished ATP level and NOX4 over expression were observed in the intoxicated groups indicating the role of Fe₂O₃-NPs in oxidative stress. A dose dependant increase in oxidative stress mediates apoptosis through upregulation of Bax, cytochrome c and cleaved caspase 3 in the 25 mg/kg treated group. Sustained oxidative stress suggest the occurrence of necrosis in addition to apoptosis in 50 mg/kg treated group evidenced by altered expression pattern of cleaved PARP, cytochrome c, Bax and cleaved caspase 3. In addition, triphenyl tetrazolium chloride (TTC) staining confirms cardiac necrosis in 50 mg/kg Fe₂O₃-NPs treated group.

Ten Things You Might Not Know about Iron Oxide Nanoparticles

Since ultrasmall superparamagnetic iron oxides (USPIOs) are not associated with a risk of nephrogenic sclerosis, they can serve as a safer contrast agents compared with gadolinium chelates for MR angiography, tissue perfusion studies, and atherosclerotic plaque and tumor imaging; USPIOs are especially beneficial for patients with renal insufficiency or patients with uncertain creatinine laboratory values.

Amid mounting concerns about nephrogenic sclerosis and gadolinium deposition in the brain, physicians and patients alike are starting to question the use of gadolinium chelates for clinical magnetic resonance (MR) imaging. The search for safer alternatives is currently underway. In North America, the iron supplement ferumoxytol has gained considerable interest as an MR contrast agent. In Europe, ferumoxtran-10 is entering phase III clinical trials. As these agents are starting to be used by a new generation of radiologists, important clinical questions have re-emerged, including those that have been answered in the past. This article offers 10 important insights for the use of iron oxide nanoparticles in clinical MR imaging.