Characterization of Magnetic Nanoparticles in Biological Matrices

Elucidating the Dynamics of Biodegradation and Biosynthesis of Magnetic Nanoparticles in Human Stem Cells

Iron oxide nanoparticles, due to their magnetic properties, are versatile tools for biomedical applications serving both diagnostic and therapeutic roles. Their performance is intricately intertwined with their fate in the demanding biological environment. Once inside cells, these nanoparticles can be degraded, implying a loss of magnetic efficacy, but also transformed into neo-synthesized magnetic nanoparticles, potentially restoring functionality. This study aims to delineate biological features governing these processes. Magnetic nanoparticles are internalized in human mesenchymal stem cells (hMSCs), and their biotransformations are investigated from nano- to micro-scale using electron microscopy (STEM-HAADF, HRTEM, SAED), a benchtop magnetic sensor, and fine structural characterizations (synchrotron XRD, VSM). Results evidence a delicate equilibrium between the biodegradation and biosynthesis of magnetic nanoparticles, with biotransformation kinetics depending on cell density at magnetic labeling and on spatial cell configuration (monolayers vs spheroids). The biotransformed nanoparticles, composed of magnetite or maghemite, are localized within endosomal/lysosomal compartments and associated with the recruitment of ferritin proteins.

Magnetic iron oxide nanoparticles@lecithin/poly (l-lactic acid) microspheres for targeted drug release in cancer therapy

The use of targeted chemotherapy is a promising solution to mitigate the side effects and dosage of drugs. This research focuses on the development of magnetic microspheres (MMS) based drug carriers for targeted chemotherapy, formulated with iron oxide nanoparticles (Fe3O4 NPs) and poly (l-lactic acid) (PLA) loaded with the antibiotic drug Ciprofloxacin (CIF). In this study, Fe3O4 NPs were synthesized using pomegranate peel extract as a natural reducing and stabilizing agent. The double emulsification method (W1/O/W2) was employed to produce Fe3O4@LEC-CIF-PLA-MMS, which were characterized using various spectral and microscopic techniques. The drug encapsulation efficiency for Fe3O4@LEC-CIF-PLA-MMS was found to be 80.7 %. The in vitro drug release of CIF from Fe3O4@LEC-CIF-PLA-MMS induced by H2O2 and GSH- stimuli was found to be 87.55 % and 82.32 %, respectively in acidic pH 4.5. Notably, the magnetically triggered drug release behaviour of Fe3O4@LEC-CIF-PLA-MMS (93.56 %) was assessed in acidic pH environment upon exposure to low-frequency alternating magnetic field (LF-AMF). Fe3O4@LEC-CIF-PLA-MMS demonstrated significantly enhanced in vitro cytotoxicity (IC50 = 0.8 ± 0.03 μg/mL) against the HeLa-S3 cancer cell lines. Nevertheless, these research findings highlight the potential of Fe3O4@LEC-CIF-PLA-MMS for further development as a chemotherapeutic agent and hold promise for the future of targeted cancer treatment.

Co-administration of temozolomide (TMZ) and the experimental therapeutic targeting miR-10b, profoundly affects the tumorigenic phenotype of human glioblastoma cells

Introduction: Recent studies have shown that miRNA-10b is highly expressed in high-grade glioblastoma multiforme (GBM), and its inhibition leads to deregulation of multiple pathways in tumorigenesis, resulting in repression of tumor growth and increased apoptosis. Thus, we hypothesized that suppressing miR-10b could enhance the cytotoxicity of conventional GBM chemotherapy with temozolomide (TMZ). Methods: Inhibition of miR-10b in glioblastoma cells was achieved using an experimental therapeutic consisting of anti-miR10b antagomirs conjugated to iron oxide nanoparticles (termed MN-anti-miR10b). The nanoparticles serve as delivery vehicles for the antagomirs as well as imaging reporters guiding the delivery in future animal studies. Results: Treatment of U251 and LN229 human glioblastoma cells with MN-anti-miR10b led to inhibition of miR-10b accompanied by repression of growth and increase in apoptosis. We next explored whether MN-anti-miR10b could enhance the cytotoxic effect of TMZ. During these studies, we unexpectedly found that TMZ monotherapy increased miR-10b expression and changed the expression of corresponding miR-10b targets. This discovery led to the design of a sequence-dependent combination treatment, in which miR-10b inhibition and induction of apoptosis by MN-anti-miR10b was followed by a sub-therapeutic dose of TMZ, which caused cell cycle arrest and ultimately cell death. This combination was highly successful in significant enhancement of apoptosis and decrease in cell migration and invasiveness. Discussion: Considering the unexpected effects of TMZ on miR-10b expression and possible implications on its clinical application, we reasoned that comprehensive in vitro studies were warranted before embarking on studies in animals. These intriguing findings serve as a solid foundation for future in vivo studies and offer promise for the successful treatment of GBM.

Applications of magnetic and electromagnetic forces in micro-analytical systems

Novel applications of magnetic fields in analytical chemistry have become a remarkable trend in the last two decades. Various magnetic forces have been employed for the migration, orientation, manipulation, and trapping of microparticles, and new analytical platforms for separating and detecting molecules have been proposed. Magnetic materials such as functional magnetic nanoparticles, magnetic nanocomposites, and specially designed magnetic solids and liquids have also been developed for analytical purposes. Numerous attractive applications of magnetic and electromagnetic forces on magnetic and non-magnetic materials have been studied, but fundamental studies to understand the working principles of magnetic forces have been challenging. These studies will form a new field of magneto-analytical science, which should be developed as an interdisciplinary field. In this review, essential pioneering works and recent attractive developments are presented.

Control of the Nanoparticles Content in Cosmetic Medicines

The safety of nanoparticles used in medical cosmetology and dermatology raises significant concerns. One of the tasks of analyzing the concentration of nanoparticles that must be solved for the practical analysis of the quality of products with nanoparticles is the quantitative analysis of the content of nanoparticles. The previously developed acousto-magnetic method (AMM) for determining the concentration of APIs as magnetic nanoparticles can be used to determine the nanoparticles' concentration when samples are prepared as a colloidal solution. It is shown that the described method not only can be applied for quality control in cosmetology and dermatology but also can be simplified by using a less sensitive magnetometer, which makes this direct method more available in the entire range of values ​​of the concentration of magnetic nanoparticles used in medical cosmetology and dermatology.

Toward a deeper and simpler understanding of serum protein-mediated transformations of magnetic nanoparticles by ICP-MS

A great variety of magnetic nanomaterials are entering preclinical investigations with the objective to select the most promising candidates for diagnostic and therapeutic applications. For an analytical approach to be used as a high-throughput screening tool, simple and cost-efficient sample preparation protocol is a basiс prerequisite. Here, we demonstrate how the application of continuous magnetic field allows for quantitatively separating iron oxide magnetic nanoparticles from a mixture with human serum to facilitate monitoring of their biomolecular interactions with high-resolution inductively coupled plasma mass spectrometry. By measuring the signals of sulfur and metal isotopes, it is possible to monitor the formation of the protein corona and alterations in the concentrations of relevant metals due to binding of specific metalloproteins, respectively.

How well can we characterize human serum transformations of magnetic nanoparticles?

This mini-review summarizes analytical methods in use to uncover biochemical transformations that magnetic nanoparticles (MNPs) are possibly undergoing while residing in human blood. Examples from the recent literature are presented to illustrate what analytical challenges are to be addressed to shed light on this important issue of biomedical application of MNPs.

High-resolution ICP-MS approach for characterization of magnetic nanoparticles for biomedical applications

The potential of iron oxide-based nanoparticles (IONs) as theranostic agents is believed to be in a great part due to non-invasive diagnosis and therapeutic applications. However, there is still a lack of well-recognized methodology to assess bioresistance, hypotoxicity, reactivity toward pertinent biomolecules, as well as an eventual dose of IONs as prerequisites for their clinical use. In this study, we demonstrate how application of high-resolution ICP-MS in combination with conventional ultrafiltration can address these important issues in a simple and high-throughput way. Based upon interference-free and sensitive measurements of iron and sulfur isotopes ensured by sector-field ICP-MS mode, the comparative testing of a series of novel IONs modified by PEG or PEG and an ionic liquid, was performed. Satisfactory stability (less than 1 % of soluble Fe), minor toxicity (by virtue of releasing a free iron) and transit into bioconjugates in human serum, different in speed, proved the prospective of the tested IONs for in-depth preclinical development.

A simple assay for probing transformations of superparamagnetic iron oxide nanoparticles in human serum

A novel approach for monitoring the biomolecular interactions of superparamagnetic nanoparticles was disclosed. Based on ultrafiltration of a human serum-nanoparticle mixture and the mass spectrometric analysis of filtrates, this assay revealed for iron oxide nanoparticles coated with poly(acrylic acid) satisfactory biopersistence and a bimodal binding to sulfur-containing biomolecules, with the formation of the protein corona completed in about 1 h.

Magnetic Iron Oxide Nanoparticles: Synthesis, Characterization and Functionalization for Biomedical Applications in the Central Nervous System

Magnetic Nanoparticles (MNPs) are of great interest in biomedicine, due to their wide range of applications. During recent years, one of the most challenging goals is the development of new strategies to finely tune the unique properties of MNPs, in order to improve their effectiveness in the biomedical field. This review provides an up-to-date overview of the methods of synthesis and functionalization of MNPs focusing on Iron Oxide Nanoparticles (IONPs). Firstly, synthesis strategies for fabricating IONPs of different composition, sizes, shapes, and structures are outlined. We describe the close link between physicochemical properties and magnetic characterization, essential to developing innovative and powerful magnetic-driven nanocarriers. In conclusion, we provide a complete background of IONPs functionalization, safety, and applications for the treatment of Central Nervous System disorders.

Synthesis of a novel magnetic nano-scale biosorbent using extracellular polymeric substances from Klebsiella sp. J1 for tetracycline adsorption

The magnetic nano-scale biosorbent (Fe₃O₄/MFX) was synthesized by the chelation and cross-linking procedure with extracellular polymeric substances (MFX) and Fe₃O₄. Fe₃O₄/MFX possessed the porous structure and numerous functional groups (i.e., amino, carboxyl, and hydroxyl), and its core region had a typical size of ∼11nm. The maximum adsorption capacity was 56.04mgg^-1 at pH 6.0, 10mgL^-1 of tetracycline, and 160mgL^-1 of Fe₃O₄/MFX. The data is properly fitted by the Langmuir, Freundlich, and pseudo-second-order kinetics models. As elucidated by the model parameters and FTIR analysis, chemical ion exchange and COOH could mainly contribute to the adsorption. Meanwhile, the desorption and regeneration experiments implied the adsorption efficiency decreased by only 3.37-8.37% after five adsorption-desorption cycles, and the detection of iron leaching by ICP-OES showed a fine stability of Fe₃O₄/MFX. Therefore, this technically facile, easily recyclable, and environmentally friendly biosorbent has potential for practical applications in antibiotic removal.

Quantification and biodistribution of iron oxide nanoparticles in the primary clearance organs of mice using T1 contrast for heating

PURPOSE

To use contrast based on longitudinal relaxation times (T₁ ) or rates (R₁ ) to quantify the biodistribution of iron oxide nanoparticles (IONPs), which are of interest for hyperthermia therapy, cell targeting, and drug delivery, within primary clearance organs.

METHODS

Mesoporous silica-coated IONPs (msIONPs) were intravenously injected into 15 naïve mice. Imaging and mapping of the longitudinal relaxation rate constant at 24 h or 1 week postinjection were performed with an echoless pulse sequence (SWIFT). Alternating magnetic field heating measurements were also performed on ex vivo tissues.

RESULTS

Signal enhancement from positive T₁ contrast caused by IONPs was observed and quantified in vivo in liver, spleen, and kidney at concentrations up to 3.2 mg Fe/(g tissue wt.) (61 mM Fe). In most cases, each organ had a linear correlation between the R₁ and the tissue iron concentration despite variations in intra-organ distribution, degradation, and IONP surface charge. Linear correlation between R₁ and volumetric SAR in hyperthermia therapy was observed.

CONCLUSION

The linear dependence between R₁ and tissue iron concentration in major organs allows quantitative monitoring of IONP biodistribution in a dosage range relevant to magnetic hyperthermia applications, which falls into the concentration gap between CT and conventional MRI techniques. Magn Reson Med 78:702-712, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Ion-Mobility-Based Quantification of Surface-Coating-Dependent Binding of Serum Albumin to Superparamagnetic Iron Oxide Nanoparticles

Protein binding and protein-induced nanoparticle aggregation are known to occur for a variety of nanomaterials, with the extent of binding and aggregation highly dependent on nanoparticle surface properties. However, often lacking are techniques that enable quantification of the extent of protein binding and aggregation, particularly for nanoparticles with polydisperse size distributions. In this study, we adapt ion mobility spectrometry (IMS) to examine the binding of bovine serum albumin to commercially available anionic-surfactant-coated superparamagnetic iron oxide nanoparticles (SPIONs), which are initially ∼21 nm in mean mobility diameter and have a polydisperse size distribution function (geometric standard deviation near 1.4). IMS, carried out with a hydrosol-to-aerosol converting nebulizer, a differential mobility analyzer, and a condensation particle counter, enables measurements of SPION size distribution functions for varying BSA/SPION number concentration ratios. IMS measurements suggest that initially (at BSA concentrations below 50 nM) BSA binds reversibly to SPION surfaces with a binding site density in the 0.05-0.08 nm(-2) range. However, at higher BSA concentrations, BSA induces SPION-SPION aggregation, evidenced by larger shifts in SPION size distribution functions (mean diameters beyond 40 nm for BSA concentrations near 100 nM) and geometric standard deviations (near 1.3) consistent with self-preserving aggregation theories. The onset of BSA aggregation is correlated with a modest but statistically significant decrease in the specific absorption rate (SAR) of SPIONs placed within an alternating magnetic field. The coating of SPIONs with mesoporous silica (MS-SPIONs) as well as PEGylation (MS-SPIONs-PEG) is found to completely mitigate BSA binding and BSA-induced aggregation; IMS-inferred size distribution functions are insensitive to BSA concentration for MS-SPIONs and MS-SPIONs-PEG. The SARs of MS-SPIONs are additionally insensitive to BSA concentration, confirming the SAR decrease is linked to BSA-induced aggregation.

The use of magnetic nanoparticles in cancer theranostics: Toward handheld diagnostic devices

Magnetic nanoparticles are frequently used in a wide range of biomedical applications. In the first part of this review the most commonly used preparation and surface coating approaches of MNPs are briefly summarized including multifunctional hybrid particles. The second part gives a detailed overview of the use of MNPs in "traditional" biomedical applications related to cancer theranostics, like magnetic resonance imaging, drug delivery, hyperthermia and also their applicability in the next generation of point of care devices based on micro nuclear magnetic resonance and surface enhanced Raman spectroscopic detection technology that all can be routinely applied in everyday clinical practice.