Search Results (132)

Background: Magnetic particle imaging (MPI) is an emerging, tracer-based modality that directly detects superparamagnetic iron oxide nanoparticles (SPIONs) with exceptional sensitivity, quantitative signal behavior, and full immunity to air–tissue susceptibility artifacts. These features make MPI particularly well-suited for pulmonary imaging, where traditional techniques such as computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine-based ventilation/perfusion (V/Q) imaging are limited by radiation exposure, low contrast, and motion-related signal degradation. Objective: This review synthesizes the current state of MPI for lung imaging, with emphasis on its physical principles, tracer development, preclinical applications, and its potential role in assessing pulmonary perfusion, vascular integrity, inflammation, and therapeutic responses. Methods: A systematic evaluation of preclinical studies was performed across three major application domains: pulmonary perfusion mapping, cell tracking and therapeutic monitoring, and vascular injury and permeability assessment. Study designs, SPION formulations, MPI acquisition strategies, and validation methods, including histopathology, biodistribution, broncho-alveolar lavage fluid (BALF) analysis, and Evans Blue assays, were examined to characterize methodological consistency and imaging performance. Results: MPI consistently demonstrated high-contrast, quantitative visualization of pulmonary blood flow, endothelial barrier disruption, inflammatory signaling, and transplanted or inhaled cell populations. Tracer engineering played a critical role: macroaggregated albumin superparamagnetic iron oxide nanoparticles (MAA-SPIONs) enabled capillary-level perfusion mapping, LS-008 improved temporal resolution and vascular delineation, Synomag/Synomag-D allowed quantification of vascular leakage in acute and chronic lung injury, and vascular cell adhesion molecule-1 (VCAM-1)-targeted probes provided molecular-level assessment of inflammation. Hybrid MPI-CT and MPI-MRI approaches further enhanced anatomic localization and enabled accurate pulmonary blood volume (PBV) estimation. Across studies, MPI measurements showed strong agreement with established biological assays and remained free of the artifacts that limit CT and MRI in the lung. Conclusions: Preclinical evidence demonstrates that MPI is a robust, radiation-free, and quantitatively precise modality for functional and molecular lung imaging. Its ability to map perfusion, track therapeutic agents, and noninvasively quantify vascular permeability positions MPI as a promising future alternative or complement to CT, MRI, and nuclear medicine for pulmonary assessment. Continued tracer optimization, system scaling, and clinical validation are key steps toward translating MPI into routine clinical use. Full article

Background: Magnetic Particle Imaging (MPI) is an emerging biomedical imaging modality that detects superparamagnetic iron oxide nanoparticles (SPIONs), providing high contrast, sensitivity, and quantification capabilities without ionizing radiation, making it particularly suitable for cancer diagnostics. Considerable engineering efforts are underway to translate MPI technology to clinical settings. Most of these MPI scanners feature a cylindrical bore geometry similar to that of other clinical imaging modalities, which limits their potential application primarily to head scanning. Methods: We have developed a single-sided MPI scanner designed to expand the modality’s applicability to other regions of the human body through a unique hardware design developed in our previous work. Imaging experiments were performed on an anatomical breast phantom containing implanted SPION point sources placed at anatomically plausible locations for breast tumors. These point sources served as artificial tumors for evaluating the system’s suitability for breast imaging applications. Results: The scanner successfully detected and clearly resolved the implanted SPION tumors in two orthogonal imaging planes. Tumor positioning was independently validated by ultrasound imaging, confirming MPI’s accurate localization. In addition, sensitivity measurements demonstrated a detection limit of 4.0 $\mathsf{\mu }\mathrm{g}$ of iron, below the estimated 4.8 $\mathsf{\mu }\mathrm{g}$ sensitivity threshold required for breast tumor detection with electronic depth scanning up to 3.5 cm deep. Conclusions: Together, these results demonstrate the capability of a single-sided MPI geometry for breast imaging applications. Imaging an anatomical breast-shaped volume presents significant challenges for MPI due to the size and accessibility constraints of conventional hardware. The results presented highlight the advantages of this approach and support its potential to extend MPI from small-animal imaging to clinically relevant applications. Full article

Background/Objectives: Magnetic nanoparticles have emerged as powerful tools for biomedical imaging, targeted drug delivery, and hyperthermia therapy. Magnetic particle imaging (MPI) is among the most promising technologies built around its properties: a radiation-free, quantitative tomographic modality that detects superparamagnetic iron oxide nanoparticles (SPIONs) directly against a biologically silent background. This review synthesizes MPI’s physical principles, nanoparticle design strategies, and preclinical applications within the broader landscape of magnetic material engineering for biomedical use. Methods: A systematic review was conducted covering MPI signal generation and image reconstruction, nanoparticle core synthesis and surface coating approaches, and preclinical applications, spanning cell tracking, oncological imaging, vascular perfusion, neuroimaging, and MPI-guided theranostics. Studies were selected to provide quantitative benchmarks and direct comparisons with competing modalities where available. Results: MPI delivers signal-to-background ratios above 1000:1, iron-mass linearity at R² ≥ 0.99, regardless of tissue depth, and acquisition rates up to 46 volumes per second. Tracer architecture—encompassing single-core particles, multicore nanoflowers, and stimuli-responsive cluster designs—is the primary determinant of sensitivity, environmental robustness, and theranostic capability. Preclinical results include detection of cell populations in the low thousands, earlier ischaemia identification than diffusion-weighted MRI, real-time drug release quantification, and spatially confined tumour hyperthermia. Three translational bottlenecks are identified: the absence of a clinically approved tracer with optimal relaxation dynamics, hardware performance losses when scaling to human-bore systems, and overestimation of passive tumour accumulation in murine models. Conclusions: MPI illustrates how progress in magnetic material design directly expands clinical imaging and theranostic possibilities. Successful translation will require indication-driven, interdisciplinary development that integrates materials science, scanner engineering, and regulatory strategy in parallel. Full article

Superparamagnetic iron oxide nanoparticles (SPIONs) are commonly produced through wet-chemical methods that require high temperature and pressure and involve multiple synthesis steps. Our research group has developed an innovative, sustainable, and patented one-step aqueous synthesis operating at ambient temperature and pressure, enabling the direct production of SPIONs in suspension. In this work, we investigated the extension of this method to obtain polymer-coated SPIONs for biomedical imaging applications. Two water-soluble and biocompatible polymers—poly(ethylene glycol) (PEG) and poly(vinyl alcohol) (PVA)—were selected and prepared into twelve samples varying in polymer concentration and iron precursor molarity. Each formulation was characterized and compared to bare SPIONs synthesized with the same approach using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and alternating gradient magnetometry (AGM). The results confirm that the one-step method yields polymer-coated nanoparticles with a cubic spinel magnetite core. PEG produced spherical, monodisperse particles (10–30 nm) exhibiting superparamagnetic behavior but lower magnetization values (1–5 emu/g). In contrast, PVA-coated nanoparticles showed a morphology dependent on polymer concentration and reagent molarity, while maintaining an average size of ~10 nm and superparamagnetic behavior, with magnetization comparable to bare SPIONs (25–50 emu/g). A preliminary MRI evaluation of a selected PVA-coated sample revealed relaxivity values of r₁ = 0.12 mM⁻¹ s⁻¹ and r₂ = 6.44 mM⁻¹ s⁻¹, supporting the potential of this synthesis route for imaging-oriented nanomaterials. Full article

A comprehensive study of the magnetic properties of baked clays containing ferrimagnetic particles in various magnetic states, including superparamagnetic, has been carried out in this work. The phase composition of the magnetic fraction of laboratory and industrial samples made from the same clay is mainly represented by iron (III) oxide polymorphs and possibly non-stoichiometric magnetite. Experimental methods included magnetic granulometry, Mössbauer spectroscopy, scanning electron microscopy, X-ray phase analysis, and pulsed electromagnetic measurements. A theoretical model of magnetostatically interacting particles with a lognormal volume distribution was used to interpret the experimental data, allowing the contribution of superparamagnetic grains to be taken into consideration. It is shown that the firing mode significantly affects the composition of iron oxide phases and their magnetic characteristics. Laboratory samples are characterized by approximately twice the proportion of superparamagnetic particles. At sufficiently low concentrations of ferrimagnet in samples <0.1%, the concentration of superparamagnetic particles is even two orders of magnitude lower. It is the use of pulse methods that provides a more reliable diagnosis of their presence. The complex application of experimental methods with theoretical modeling makes it possible to reveal and quantitatively describe the microheterogeneous nature of the magnetic state of baked clays, which is applicable to a wide range of magnetic materials, and to analyze more deeply the thermal and phase history of archaeological and geological objects. Full article

Magnetic Particle Imaging (MPI) is a new type of tracer-based imaging that has great spatial and temporal resolution, does not require ionizing radiation, and can see deep into tissues by directly measuring the nonlinear magnetization response of superparamagnetic iron oxide nanoparticles (SPIONs). Unlike Magnetic Resonance Imaging (MRI) or Computed Tomography (CT), MPI has very high contrast and quantitative accuracy, which makes it perfect for use in dynamic cardiovascular applications. This study presents a full picture of the most recent changes in cardiac MPI, such as the physics behind Field-Free Point (FFP) and Field-Free Line (FFL) encoding, new ideas for tracer design, and important steps in the evolution of scanner hardware. We discuss the clinical relevance of cardiac MPI in visualizing myocardial perfusion, quantifying blood flow, and guiding real-time interventions. A hybrid imaging workflow, which improves anatomical detail and functional assessment, is utilized to explore the integration of MPI with complementary modalities, particularly MRI. By consolidating recent preclinical breakthroughs and highlighting the roadmap toward human-scale implementation, this article underscores the transformative potential of MPI in cardiac diagnostics and image-guided therapy. Full article

Magnetic Particle Imaging (MPI) is a cutting-edge noninvasive imaging technique that offers high sensitivity, quantitative accuracy, and operates without the need for ionizing radiation compared to other imaging techniques. Utilizing superparamagnetic iron oxide nanoparticles (SPIONs) as tracers, MPI enables direct and precise visualization of target sites with no limitation on imaging depth. Unlike magnetic resonance imaging (MRI), which relies on uniform magnetic fields to produce anatomical images, MPI enables direct, background-free visualization and quantification of SPIONS within living organisms. This article provides an in-depth overview of MPI’s applications in tracking tumor development and supporting cancer therapy. The distinct physical principles that underpin MPI, including its ability to produce high-contrast images devoid of background tissue interference, facilitating accurate tumor identification and real-time monitoring of treatment outcomes, are outlined. The review outlines MPI’s advantages over conventional imaging techniques in terms of sensitivity and resolution, and examines its capabilities in visualizing tumor vasculature, tracking cellular movement, evaluating inflammation, and conducting magnetic hyperthermia treatments. Recent progress in tracer optimization and magnetic navigation has expanded MPI’s potential for targeted drug delivery, along with deep machine learning procedures for MPI applications. Additionally, considerations around safety and the feasibility of clinical implementation are also discussed in the present review. Overall, MPI is positioned as a promising tool in advancing cancer diagnostics, personalized therapy assessment, and noninvasive treatment strategies. Full article

Superparamagnetic iron oxide nanoparticles (SPIONs) with sizes below 10 nm are biocompatible and non-toxic, making them promising for biomedical applications. To prevent their agglomeration and enhance their functionality, the nanoparticles were coated with citric acid (CA), which modifies the surface charge, improves dispersion stability, and facilitates biomedical use. In this work, a modular flow-through microreactor system was employed to synthesize and coat the nanoparticles in a single, continuous two-step process. The system enables precise control over temperature and mixing, ensuring uniform reaction conditions and minimizing hot spots. The synthesized Fe₃O₄ nanoparticles exhibited an average crystallite size of ~5 nm (XRD) and particle sizes of 4–6 nm (TEM). FTIR analysis confirmed the successful surface functionalization with CA, while TGA indicated a coating mass fraction of approximately 4–20 wt%, increasing with higher CA concentration. Zeta potential measurements revealed strong colloidal stability, with values around −35 mV at pH 6.5. Among the tested CA concentrations, the sample with a molar ratio of Fe₃O₄:CA = 1:0.25 exhibited the most favorable properties, including narrow size distribution and improved dispersion stability. These findings demonstrate that the continuous modular flow approach enables the reproducible synthesis of highly stable, sub-10 nm CA-coated SPIONs, offering promising potential for biomedical applications, particularly as magnetic resonance imaging (MRI) contrast agents. Full article

Neurodegenerative disorders (NDs), including Alzheimer’s disease and Parkinson’s disease, pose a significant global health challenge characterized by progressive neuronal loss and limited therapeutic options. Early diagnosis remains a considerable hurdle due to the absence of reliable biomarkers and the restrictive nature of the blood–brain barrier (BBB), which complicates effective drug delivery. Magnetic nanoparticles (MNPs), particularly those based on iron oxide, have emerged as promising tools for both diagnostic and therapeutic applications in NDs, thanks to their superparamagnetism, biocompatibility, and customizable surfaces. This review examines various synthesis strategies for MNPs, encompassing physical methods (such as lithography, ball milling, and laser ablation) and chemical approaches (co-precipitation, thermal decomposition, hydrothermal synthesis, sol–gel processes, and polyacrylamide gel techniques), while highlighting how these techniques influence particle properties. This review also explores recent advancements in surface functionalization using polymers and coatings to enhance circulation time in the bloodstream and improve BBB penetration for targeted delivery. Furthermore, it emphasizes both in vitro and in vivo applications, showcasing MNPs’ effectiveness in enhancing imaging sensitivity and enabling targeted drug and gene delivery. By linking synthesis methods, functionalization techniques, and biomedical outcomes, this review illustrates the transformative potential of MNPs as next-generation theranostic agents in precision medicine for neurodegenerative diseases. Full article

Nanotechnology, specifically magnetic nanoparticles (MNPs), is revolutionizing cancer treatment. Magnetic hyperthermia is a treatment that, using MNPs, can selectively kill cancer cells without causing damage to the surrounding tissues. Background/Objectives: This work aimed to analyze how the synthesis conditions, namely, how the pH of the reaction can influence the magnetic properties of Fe₃O₄ nanoparticles for magnetic hyperthermia, using the hydrothermal synthesis. Methods: For the hydrothermal synthesis, FeCl₃·6H₂O and FeCl₂·4H₂O were mixed with different quantities of NaOH to adjust the pH. After obtaining a black precipitate, the samples were placed in an autoclave at 200 °C for 60 h, followed by a washing and drying phase. The obtained MNPs were analyzed using X-Ray Diffraction (XRD), Transmission Electron Microscopy, a Superconducting Quantum Interference Device, Specific Absorption Rate analysis, and cytotoxicity assays. Results: Different MNPs were analyzed (9.06 < pH < 12.75). The XRD results showed the presence of various iron oxide phases (magnetite, maghemite, and hematite), resulting from the oxidization of the iron phases present in the autoclave. In terms of the average particle size, it was verified that, by increasing the pH value, the size decreases (from 53.53 nm to 9.49 nm). Additionally, MNPs possess a superparamagnetic behaviour with high SAR values (above 69.3 W/g). Conclusions: It was found that the pH of the reaction can influence the size, morphology, magnetization, and thermal efficiency of the MNP. The MNP with the highest composition of Fe₃O₄ was synthesized with a pH of 12.75, with a cubic morphology and a SAR value of 92.7 ± 3.2 W/g. Full article

Superparamagnetic iron oxide (SPIO) nanoparticles are a promising platform for drug delivery and magnetic resonance imaging (MRI). However, complement activation and immune recognition remain major barriers to their clinical translation. Previously, we reported that dextran-coated SPIO nanoworms (NWs) trigger potent complement activation and infusion reactions. Here, we systematically map the temporal sequence of immune events following SPIO NW administration, including C3 opsonization, granulocyte uptake, and cytokine release. In both in vitro and in vivo models, C3 deposition occurred rapidly, peaking at approximately 5 min post-incubation or post-injection. Higher Fe/plasma ratios led to reduced C3 deposition per particle, although the absolute amount of C3 bound was greater in vivo than in vitro. Notably, C3 dissociation from the particle surface exhibited a consistent half-life of ~14 min, independent of the NW injected dose and circulation time. Immune uptake by blood granulocytes was delayed relative to opsonization, becoming prominent only at 60 min post-injection. Further, cytokine release, measured by plasma IL-6 levels, displayed an even slower profile, with peak expression at 6 h post-injection. Together, these results reveal a distinct sequential immune response to SPIO NWs: rapid C3 opsonization, delayed cellular uptake, and late cytokine response. Understanding these dynamics provides a basis for developing strategies to inhibit complement activation and improve the hemocompatibility of SPIO-based theranostic agents. Full article

Stem-cell-based therapies rely on the transplantation of stem cells or stem-cell-derived organotypic cells into injured tissues in order to improve or restore tissue function that has been impaired by various diseases. The potential of induced pluripotent stem cells has created many applications in the field of cell therapy, for example. Some applications, for example, those in cardiac cell therapy, suffer from low or very low efficiencies of cell engraftment. Therefore, magnetic cell targeting can be discussed as a method for capturing superparamagnetic nanoparticle-labelled cells in the tissue. Here, we employ superparamagnetic iron oxide nanoparticles (SPIONs) for the intracellular magnetic loading of mesenchymal stem cells (MSCs). In addition, we test a novel strategy of labelling MSCs with ferromagnetic particles. The adhesion assays demonstrate a faster adhesion kinetic of SPIONs-loaded MSC spheroids when a magnetic field was applied, resulting in >50% spheroid adhesion after 30 min. Clustering of cells inside the magnetic field is a second potential mechanism of magnetic cell retention and >80% of cells were found to be aggregated in clusters when placed in a magnetic field for 10 min. SPIONs-loaded and ferromagnetic-particle-loaded cells performed equally in the cell clustering assay. In conclusion, the clustering of SPION-labelled cells explains the observation that magnetic targeting reaches maximal efficiency in vivo after only 10 min of magnetic field application. This has significant implications for magnetic-targeting-assisted stem cell and cell replacement therapies. Full article

Background/Objectives: Nanocarrier particle design for treating chronic pulmonary diseases presents several challenges, including anatomical and physiological barriers. Drug-repurposing technology using monodispersed spherical silica is one of the innovative ways to deliver drugs. In the present study, the anticancer potential of combinational cisplatin/ribavirin was explored for targeted lung cancer therapeutics. Methods: Monodispersed spherical silica (80 nm) capable of diffusing into the tracheal mucus region was chosen and doped with 10 wt% superparamagnetic iron oxide nanoparticles (SPIONs). Subsequently, it was wrapped with chitosan (Chi, 0.6 wt/vol%), functionalized with 5% wt/wt cisplatin (Cp)/ribavarin (Rib) and angiotensin-converting enzyme 2 (ACE-2) (1.0 μL/mL). Formulations are based on monodispersed spherical silica or halloysite and are termed as (S/MSSiO₂/Chi/Cp/Rib) or (S/Hal/Chi/Cp/Rib), respectively. Results: X-ray diffraction (XRD) and diffuse reflectance UV-visible spectroscopy (DRS-UV-vis) analysis of S/MSSiO₂/Chi/Cp/Rib confirmed the presence of SPION nanoclusters on the silica surface (45% coverage). The wrapping of chitosan on the silica was confirmed with a Fourier transformed infrared (FTIR) stretching band at 670 cm⁻¹ and ascribed to the amide group of the polymer. The surface charge by zetasizer and saturation magnetization by vibrating sample magnetometer (VSM) were found to be −15.3 mV and 8.4 emu/g. The dialysis membrane technique was used to study the Cp and Rib release between the tumor microenvironment and normal pH ranges from 5.5 to 7.4. S/MSSiO₂/Chi formulation demonstrated pH-responsive Cp and Rib at acidic pH (5.6) and normal pH (7.4). Cp and Rib showed release of ~27% and ~17% at pH 5.6, which decreases to ~14% and ~3.2% at pH 7.4, respectively. To assess the compatibility and cytotoxic effect of our nanocomposites, the cell viability assay (MTT) was conducted on cancer lung cells A549 and normal HEK293 cells. Conclusions: The study shows that the designed nanoformulations with multifunctional capabilities are able to diffuse into the lung cells bound with dual drugs and the ACE-2 receptor. Full article

The colloidal long-storage stability of nanosized drugs is a crucial factor for pharmacology, as they require much time for robust estimation. The application of bioavailable magnetic nanosuspensions in theranostics is limited by incomplete information about their colloidal stability in the internal media of human organisms. A method for the accelerated temperature stress “aging” of magnetic nanosized suspensions is proposed for the rapid assessment and prediction of the colloidal stability over time of nanosized iron oxide suspensions stabilized by albumin HSA. Colloidal stability is assessed using dynamic light scattering (DLS), fluorescence spectroscopy, electrophoresis, and ion monitoring methods during short- and long-term storage. Rapid assessment is achieved by short high-temperature (70 °C) processing of carboxymethyl-dextran-coated nanosol in the presence of albumin. The role of albumin in the sustained stability of superparamagnetic iron oxide particles (SPIONs) was studied under conditions mimicking blood plasma (pH = 7.4) and endolysosomal cell compartments (pH = 5.5). According to the fluorescence quenching and DLS data, colloidal stability is ensured by the formation of an HSA corona on carboxymethyl-dextran-coated SPIONs and their process of clustering. In the presence of albumin, the colloidal stability of nanoparticles is shown to increase from 80 to 121 days at a storage temperature of 8 °C The prognostic shelf life of magnetic nanosol is estimated by calculating the Van’t Hoff’s relation for the rate of chemical reactions. The validity of using the Van’t Hoff’s rule is confirmed by the agreement of the calculated activation energy at 8 °C and 70 °C. The developed method of the accelerated aging of nanoparticles can not only be employed for the estimation of the shelf life of magnetic nanoparticles coated with HSA in vitro but also for assessing the stability of SPIONs applied in vivo. Full article

Objective: This study aims to develop an intranasal (IN) delivery system for glioblastoma multiforme (GBM) management using repurposed superparamagnetic iron-oxide (SPION) loaded with atorvastatin (ATO)-nanostructured lipid carrier (NLC). Methods: Emulsification and ultrasonication were used to formulate ATO-NLCs, and the best formula was loaded with SPION to make the final atorvastatin/superparamagnetic iron oxide-loaded nanostructured lipid carrier (ASN) formulation. Entrapment efficiency (EE%), particle size (PS), zeta potential (ZP), and drug release after 6 h (Q6h) were evaluated for NLCs. ASN was tested for cytotoxicity on T98G cancer cells, and the cell cycle was examined to determine cell death. Furthermore, the ability of the optimal formulation to suppress the levels of inflammatory biomarkers was investigated in Lipopolysaccharide (LPS)-induced inflammation. The brain-targeting behavior of IN-ASN was visualized in rabbits via confocal laser scanning microscopy (CLSM). Results: The optimum NLC exhibited a spherical shape, EE% of 84.0 ± 0.67%, PS of 282.50 ± 0.51 nm, ZP of −18.40 ± 0.15 mV, and Q6h of 89.23%. The cytotoxicity of ASN against cancer cells was 4.4-fold higher than ATO suspension, with a 1.3-fold increment in cell apoptosis. ASN showed significantly reduced pro-inflammatory biomarkers (IL-β, IL-6, TNF-α, TLR4, NF-қB), whereas CLSM revealed enhanced brain delivery with no observed histopathological nasal irritation. The in silico analysis demonstrated enhanced ATO-ADME (absorption, distribution, metabolism, and excretion) properties, while the network pharmacology study identified 10 target GBM genes, among which MAPK3 was the most prominent with a good binding score as elucidated by the simulated docking study. Conclusions: These findings may present ATO/SPION-NLCs as significant evidence for repurposing atorvastatin in the treatment of glioblastoma multiforme. Full article