Polymer-coated superparamagnetic iron oxide nanoparticles as T2 contrast agent for MRI and their uptake in liver

Effect of Polymer and Cell Membrane Coatings on Theranostic Applications of Nanoparticles: A Review

The recent decade has witnessed a remarkable surge in the field of nanoparticles, from their synthesis, characterization, and functionalization to diverse applications. At the nanoscale, these particles exhibit distinct physicochemical properties compared to their bulk counterparts, enabling a multitude of applications spanning energy, catalysis, environmental remediation, biomedicine, and beyond. This review focuses on specific nanoparticle categories, including magnetic, gold, silver, and quantum dots (QDs), as well as hybrid variants, specifically tailored for biomedical applications. A comprehensive review and comparison of prevalent chemical, physical, and biological synthesis methods are presented. To enhance biocompatibility and colloidal stability, and facilitate surface modification and cargo/agent loading, nanoparticle surfaces are coated with different synthetic polymers and very recently, cell membrane coatings. The utilization of polymer- or cell membrane-coated nanoparticles opens a wide variety of biomedical applications such as magnetic resonance imaging (MRI), hyperthermia, photothermia, sample enrichment, bioassays, drug delivery, etc. With this review, the goal is to provide a comprehensive toolbox of insights into polymer or cell membrane-coated nanoparticles and their biomedical applications, while also addressing the challenges involved in translating such nanoparticles from laboratory benchtops to in vitro and in vivo applications. Furthermore, perspectives on future trends and developments in this rapidly evolving domain are provided.

Multifunctional Fluoropolymer-Engineered Magnetic Nanoparticles to Facilitate Blood-Brain Barrier Penetration and Effective Gene Silencing in Medulloblastoma

Patients with brain cancers including medulloblastoma lack treatments that are effective long-term and without side effects. In this study, a multifunctional fluoropolymer-engineered iron oxide nanoparticle gene-therapeutic platform is presented to overcome these challenges. The fluoropolymers are designed and synthesized to incorporate various properties including robust anchoring moieties for efficient surface coating, cationic components to facilitate short interference RNA (siRNA) binding, and a fluorinated tail to ensure stability in serum. The blood-brain barrier (BBB) tailored system demonstrates enhanced BBB penetration, facilitates delivery of functionally active siRNA to medulloblastoma cells, and delivers a significant, almost complete block in protein expression within an in vitro extracellular acidic environment (pH 6.7) - as favored by most cancer cells. In vivo, it effectively crosses an intact BBB, provides contrast for magnetic resonance imaging (MRI), and delivers siRNA capable of slowing tumor growth without causing signs of toxicity - meaning it possesses a safe theranostic function. The pioneering methodology applied shows significant promise in the advancement of brain and tumor microenvironment-focused MRI-siRNA theranostics for the better treatment and diagnosis of medulloblastoma.

PEG-Coated MnZn Ferrite Nanoparticles with Hierarchical Structure as MRI Contrast Agent

In this work, MnZn ferrite nanoparticles with hierarchical morphology were synthesized hydrothermally, and their surface characteristics were improved by the PEGylation process. In vitro MRI studies were also conducted to evaluate the ability of the synthesized nanoparticles as a contrast agent. All results were compared with those obtained for MnZn ferrite nanoparticles with normal structure. Microstructural evaluations showed that in ferrite with hierarchical morphology, the spherical particles with an average size of ~20 nm made a distinctive structure consisting of rows of nanoparticles which is a relatively big assembly like a dandelion. The smaller particle size and dandelion-like morphology led to an increase in specific surface area for the hierarchical structure (~69 m²/g) in comparison to the normal one (~30 m²/g) with an average particle size of ~40 nm. In vitro MRI, cytotoxicity and hemocompatibility assays confirmed the PEG-coated MnZn ferrite nanoparticles with hierarchical structure synthesized in the current study can be considered as an MRI contrast agent.

The Anti-Obesity Potential of Superparamagnetic Iron Oxide Nanoparticles against High-Fat Diet-Induced Obesity in Rats: Possible Involvement of Mitochondrial Biogenesis in the Adipose Tissues

BACKGROUND

Obesity is a pandemic disease that is rapidly growing into a serious health problem and has economic impact on healthcare systems. This bleak image has elicited creative responses, and nanotechnology is a promising approach in obesity treatment. This study aimed to investigate the anti-obesity effect of superparamagnetic iron oxide nanoparticles (SPIONs) on a high-fat-diet rat model of obesity and compared their effect to a traditional anti-obesity drug (orlistat).

METHODS

The obese rats were treated daily with orlistat and/or SPIONs once per week for 8 weeks. At the end of the experiment, blood samples were collected for biochemical assays. Then, the animals were sacrificed to obtain white adipose tissues (WAT) and brown adipose tissues (BAT) for assessment of the expression of thermogenic genes and mitochondrial DNA copy number (mtDNA-CN).

RESULTS

For the first time, we reported promising ameliorating effects of SPIONs treatments against weight gain, hyperglycemia, adiponectin, leptin, and dyslipidemia in obese rats. At the molecular level, surprisingly, SPIONs treatments markedly corrected the disturbed expression and protein content of inflammatory markers and parameters controlling mitochondrial biogenesis and functions in BAT and WAT.

CONCLUSIONS

SPIONs have a powerful anti-obesity effect by acting as an inducer of WAT browning and activator of BAT functions.

Advantages and Disadvantages of Using Magnetic Nanoparticles for the Treatment of Complicated Ocular Disorders

Nanomaterials provide enormous opportunities to overcome the limitations of conventional ocular delivery systems, such as low therapeutic efficacy, side effects due to the systemic exposure, or invasive surgery. Apart from the more common ocular disorders, there are some genetic diseases, such as cystic fibrosis, that develop ocular disorders as secondary effects as long as the disease progresses. These patients are more difficult to be pharmacologically treated using conventional drug routes (topically, systemic), since specific pharmacological formulations can be incompatible, display increased toxicity, or their therapeutic efficacy decreases with the administration of different kind of chemical molecules. Magnetic nanoparticles can be used as potent drug carriers and magnetic hyperthermia agents due to their response to an external magnetic field. Drugs can be concentrated in the target point, limiting the damage to other tissues. The other advantage of these magnetic nanoparticles is that they can act as magnetic resonance imaging agents, allowing the detection of the exact location of the disease. However, there are some drawbacks related to their use in drug delivery, such as the limitation to maintain efficacy in the target organ once the magnetic field is removed from outside. Another disadvantage is the difficulty in maintaining the therapeutic action in three dimensions inside the human body. This review summarizes all the application possibilities related to magnetic nanoparticles in ocular diseases.

Micron-sized iron oxide particles for both MRI cell tracking and magnetic fluid hyperthermia treatment

Iron oxide particles (IOP) are commonly used for Cellular Magnetic Resonance Imaging (MRI) and in combination with several treatments, like Magnetic Fluid Hyperthermia (MFH), due to the rise in temperature they provoke under an Alternating Magnetic Field (AMF). Micrometric IOP have a high sensitivity of detection. Nevertheless, little is known about their internalization processes or their potential heat power. Two micrometric commercial IOP (from Bangs Laboratories and Chemicell) were characterized by Transmission Electron Microscopy (TEM) and their endocytic pathways into glioma cells were analyzed. Their Specific Absorption Rate (SAR) and cytotoxicity were evaluated using a commercial AMF inductor. T2-weighted imaging was used to monitor tumor growth in vivo after MFH treatment in mice. The two micron-sized IOP had similar structures and r2 relaxivities (100 mM-1 s-1) but involved different endocytic pathways. Only ScreenMAG particles generated a significant rise in temperature following AMF (SAR = 113 W g-1 Fe). After 1 h of AMF exposure, 60% of ScreenMAG-labeled cells died. Translated to a glioma model, 89% of mice responded to the treatment with smaller tumor volume 42 days post-implantation. Micrometric particles were investigated from their characterization to their intracellular internalization pathways and applied in one in vivo cancer treatment, i.e. MFH.

Magnetic Colloidal Particles in Combinatorial Thin-Film Gradients for Magnetic Resonance Imaging and Hyperthermia

A stable oil-in-water (O/W) magnetic emulsion was prepared by the emulsification of organic ferrofluid in an aqueous media, and its theranostic applications were investigated. The synthesis and characterization of the organic ferrofluid were carried out comprising of superparamagnetic maghemite nanoparticles with oleic acid coating stabilized in octane. Both exhibit spherical morphology with a mean size of 6 nm and 200 nm, respectively, as determined by TEM. Thermogravimetric analysis was carried out to determine the chemical composition of the emulsion. The research work described here is novel and elaborates the fabrication of thin-film gradients with 5, 10, 15, and 20 bilayers by layer-by-layer technique using polydimethyl diallyl ammonium chloride (PDAC) and prepared magnetic colloidal particles. The thin-film gradients were characterized for their roughness, morphology, and wettability. The developed gradient films and colloids were explored in magnetic resonance imaging (MRI) and hyperthermia. T1- and T2-weighted images and their corresponding signal intensities were obtained at 1.5 T. A decreasing trend in signal intensities with an increase in nanoparticle concentration in colloids and along the gradient was observed in T2-weighted images. The hyperthermia capability was also evaluated by measuring temperature rise and calculating specific absorption rates (SAR). The SAR of the colloids at 259 kHz, 327 kHz, and 518 kHz were found to be 156 W/g, 255 W/g, and 336 W/g, respectively. The developed magnetic combinatorial thin-film gradients present a significant potential for the future efficient simultaneous diagnostic and therapeutic bioapplications.

Magnetic Nanomaterials as Contrast Agents for MRI

Magnetic Resonance Imaging (MRI) is a powerful, noninvasive and nondestructive technique, capable of providing three-dimensional (3D) images of living organisms. The use of magnetic contrast agents has allowed clinical researchers and analysts to significantly increase the sensitivity and specificity of MRI, since these agents change the intrinsic properties of the tissues within a living organism, increasing the information present in the images. Advances in nanotechnology and materials science, as well as the research of new magnetic effects, have been the driving forces that are propelling forward the use of magnetic nanostructures as promising alternatives to commercial contrast agents used in MRI. This review discusses the principles associated with the use of contrast agents in MRI, as well as the most recent reports focused on nanostructured contrast agents. The potential applications of gadolinium- (Gd) and manganese- (Mn) based nanomaterials and iron oxide nanoparticles in this imaging technique are discussed as well, from their magnetic behavior to the commonly used materials and nanoarchitectures. Additionally, recent efforts to develop new types of contrast agents based on synthetic antiferromagnetic and high aspect ratio nanostructures are also addressed. Furthermore, the application of these materials in theragnosis, either as contrast agents and controlled drug release systems, contrast agents and thermal therapy materials or contrast agents and radiosensitizers, is also presented.

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.

Multifunctional Fe3O4@C-based nanoparticles coupling optical/MRI imaging and pH/photothermal controllable drug release as efficient anti-cancer drug delivery platforms

Multifunctional nanomedicines featuring high drug loading capacity, controllable drug release and real-time self-monitoring are attracting increasing attention due to their potential to improve cancer therapeutic efficacy. Herein, a new kind of Fe₃O₄@C-based nanoparticles modified with isoreticular metal organic frameworks (IRMOF-3), folic acid (FA) and detachable polyethylene glycol (PEG) under tumor microenvironment was developed. The core-shell structured Fe₃O₄@C was synthesized via the one-pot solvothermal reaction and the IRMOF-3 layers were coated on the outer shell of Fe₃O₄@C through layer-by-layer coating method. The FA and PEG were conjugated on the surface of nanoparticles by reacting with the amine groups provided by IRMOF-3. The as-synthesized nanoparticles showed stable photothermal effect, superparamagnetic properties and blue fluorescence characteristic under 360 nm irradiation. The in vitro experiments showed that the drug loaded nanoparticles exhibit pH-dependent drug release property, and PEGylation was proved effective in suppressing burst drug release (only 8.0% of drugs were released within 95 h). The confocal laser scanning microscopy study revealed that the as-synthesized nanoparticles could serve as a cell imaging agent and the cell internalization can be significantly enhanced after FA modified. The IRMOF-3 modified nanoparticles showed negligible cytotoxicity and the drug loaded nanoparticles showed pH/photothermal-stimuli enhanced cytotoxicity in vitro. It is believed that the present smart drug delivery platforms will hold great potential in imaging guided drug delivery and cancer therapy.