Assisted Synthesis of Coated Iron Oxide Nanoparticles for Magnetic Hyperthermia

Evaluating the impact of cell-penetrating motif position on the cellular uptake of magnetite nanoparticles

Cell-penetrating peptides (CPPs) have been employed to enhance the cellular uptake and intracellular delivery of various nanocarriers. Among them, nanoparticles (NPs) have been used as suitable vehicles for delivering different bioactive molecules in the treatment of a diverse range of diseases. Given the pivotal role of the conjugation method of CPPs, this study aims to evaluate the impact of the position of a cell-penetrating motif (LFVCR) on the biocompatibility, cellular uptake, and endosomal escape of magnetite NPs. The designed peptide's physicochemical properties suggest they are well-suited for efficient cell penetration with minimal cytotoxicity. The resulting designed nanoconjugates were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and transmission electron microscopy (TEM). The results indicate that motif position significantly impacts the cellular uptake and endosomal escape of the designed nanobioconjugates. Key findings suggest that motif exposure enhances endocytosis-mediated cell internalization and improves endosomal escape efficiency. These results were compared with nanobioconjugates displaying previously reported CPPs. The selected nanobioconjugate demonstrated superior performance in endosomal escape and comparable cell uptake to the reference nanobioconjugates. These results, along with the nanobioconjugate's physicochemical characteristics and high biocompatibility, position the nanocarrier as a suitable candidate for delivering diverse bioactive molecules.

Cytotoxic evaluation of pure and doped iron oxide nanoparticles on cancer cells: a magnetic fluid hyperthermia perspective

The need of the hour with respect to cancer treatment is a targeted approach with minimal or nil ramifications. Apropos, magnetic fluid hyperthermia (MFH) is emerging as a potential therapeutic strategy with anticipated reduced side effects for solid tumors. MFH causes cytotoxicity due to the heat generated owing to Hysteresis, Neel, and Brownian relaxation losses once magnetic nanoparticles (MNPs) carrying cancer cells are placed under an alternating magnetic field. With respect to MFH, iron oxide-based MNPs have been most extensively studied to date compared to other metal oxides with magnetic properties. The effectiveness of MFH relies on the composition, coating, size, physical and biocompatible properties of the MNPs. Pure iron oxide and doped iron oxide MNPs have been utilized to study their effects on cancer cell killing through MFH. This review evaluates the biocompatibility of pure and doped iron oxide MNPs and their subsequent hyperthermic effect for effectively killing cancer cells in vitro and in vivo.

Iron nanoparticles as food additives and food supplements, regulatory and legislative perspectives

Recently, the use of nanotechnology in food has gained great interest. Iron nanoparticles with unique chemical, physical and structural properties allow their potential use mainly as iron fortifiers, colorants and antimicrobial agents. However, in the market we can find only supplements and food colorants based on iron nanoparticles. Their use in food fortification has so far been focused only on in vitro and in vivo experimental studies, since the toxicological evaluation of these studies has so far been the basis for the proposals of laws and regulations, which are still in an early stage of development. Therefore, the aim of this work was to summarize the use of the different forms of iron nanoparticles (oxides, oxyhydroxides, phosphates, pyrophosphates and sulfates) as food additives and supplements and to resume the perspectives of legislation regarding the use of these types of nanoparticles in the food industry.

Electrospun Magnetic Nanofiber Mats for Magnetic Hyperthermia in Cancer Treatment Applications-Technology, Mechanism, and Materials

The number of cancer patients is rapidly increasing worldwide. Among the leading causes of human death, cancer can be regarded as one of the major threats to humans. Although many new cancer treatment procedures such as chemotherapy, radiotherapy, and surgical methods are nowadays being developed and used for testing purposes, results show limited efficiency and high toxicity, even if they have the potential to damage cancer cells in the process. In contrast, magnetic hyperthermia is a field that originated from the use of magnetic nanomaterials, which, due to their magnetic properties and other characteristics, are used in many clinical trials as one of the solutions for cancer treatment. Magnetic nanomaterials can increase the temperature of nanoparticles located in tumor tissue by applying an alternating magnetic field. A very simple, inexpensive, and environmentally friendly method is the fabrication of various types of functional nanostructures by adding magnetic additives to the spinning solution in the electrospinning process, which can overcome the limitations of this challenging treatment process. Here, we review recently developed electrospun magnetic nanofiber mats and magnetic nanomaterials that support magnetic hyperthermia therapy, targeted drug delivery, diagnostic and therapeutic tools, and techniques for cancer treatment.

Metal and Metal Oxides Nanoparticles and Nanosystems in Anticancer and Antiviral Theragnostic Agents

The development of antiviral treatment and anticancer theragnostic agents in recent decades has been associated with nanotechnologies, and primarily with inorganic nanoparticles (INPs) of metal and metal oxides. The large specific surface area and its high activity make it easy to functionalize INPs with various coatings (to increase their stability and reduce toxicity), specific agents (allowing retention of INPs in the affected organ or tissue), and drug molecules (for antitumor and antiviral therapy). The ability of magnetic nanoparticles (MNPs) of iron oxides and ferrites to enhance proton relaxation in specific tissues and serve as magnetic resonance imaging contrast agents is one of the most promising applications of nanomedicine. Activation of MNPs during hyperthermia by an external alternating magnetic field is a promising method for targeted cancer therapy. As therapeutic tools, INPs are promising carriers for targeted delivery of pharmaceuticals (either anticancer or antiviral) via magnetic drug targeting (in case of MNPs), passive or active (by attaching high affinity ligands) targeting. The plasmonic properties of Au nanoparticles (NPs) and their application for plasmonic photothermal and photodynamic therapies have been extensively explored recently in tumor treatment. The Ag NPs alone and in combination with antiviral medicines reveal new possibilities in antiviral therapy. The prospects and possibilities of INPs in relation to magnetic hyperthermia, plasmonic photothermal and photodynamic therapies, magnetic resonance imaging, targeted delivery in the framework of antitumor theragnostic and antiviral therapy are presented in this review.

In Vitro Studies of Pegylated Magnetite Nanoparticles in a Cellular Model of Viral Oncogenesis: Initial Studies to Evaluate Their Potential as a Future Theranostic Tool

Magnetic nanosystems represent promising alternatives to the traditional diagnostic and treatment procedures available for different pathologies. In this work, a series of biological tests are proposed, aiming to validate a magnetic nanoplatform for Kaposi's sarcoma treatment. The selected nanosystems were polyethylene glycol-coated iron oxide nanoparticles (MAG.PEG), which were prepared by the hydrothermal method. Physicochemical characterization was performed to verify their suitable physicochemical properties to be administered in vivo. Exhaustive biological assays were conducted, aiming to validate this platform in a specific biomedical field related to viral oncogenesis diseases. As a first step, the MAG.PEG cytotoxicity was evaluated in a cellular model of Kaposi's sarcoma. By phase contrast microscopy, it was found that cell morphology remained unchanged regardless of the nanoparticles' concentration (1-150 µg mL^-1). The results, arising from the crystal violet technique, revealed that the proliferation was also unaffected. In addition, cell viability analysis by MTS and neutral red assays revealed a significant increase in metabolic and lysosomal activity at high concentrations of MAG.PEG (100-150 µg mL^-1). Moreover, an increase in ROS levels was observed at the highest concentration of MAG.PEG. Second, the iron quantification assays performed by Prussian blue staining showed that MAG.PEG cellular accumulation is dose dependent. Furthermore, the presence of vesicles containing MAG.PEG inside the cells was confirmed by TEM. Finally, the MAG.PEG steering was achieved using a static magnetic field generated by a moderate power magnet. In conclusion, MAG.PEG at a moderate concentration would be a suitable drug carrier for Kaposi's sarcoma treatment, avoiding adverse effects on normal tissues. The data included in this contribution appear as the first stage in proposing this platform as a suitable future theranostic to improve Kaposi's sarcoma therapy.

Synthesis and Characterization of Citric Acid-Modified Iron Oxide Nanoparticles Prepared with Electrohydraulic Discharge Treatment

Chemical co-precipitation from ferrous and ferric salts at a 1:1.9 stoichiometric ratio in NH₄OH base with ultrasonication (sonolysis) in a low vacuum environment has been used for obtaining colloidal suspensions of Fe₃O₄ nanoparticles coated with citric acid. Before coating, the nanoparticles were processed by electrohydraulic discharges with a high discharge current (several tens of amperes) in a water medium using a pulsed direct current. Magnetite nanoparticles were obtained with an average crystallite diameter D = 25-28 nm as obtained by XRD and particle sizes of 25 nm as measured by small-angle X-ray scattering. Magnetometry showed that all samples were superparamagnetic. The saturation magnetization for the citric acid covered samples after electrohydraulic processing showed higher value (58 emu/g) than for the directly coated samples (50 emu/g). Ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy showed the presence and binding of citric acid to the magnetite surface by chemisorption of carboxylate ions. Hydrodynamic sizes obtained from DLS and zeta potentials were 93 and 115 nm, -26 and -32 mV for the citric acid covered nanoparticles and 226 nm and 21 mV for the bare nanoparticles, respectively. The hydraulic discharge treatment resulted in a higher citric acid coverage and better particle dispersion. The developed method can be used in nanoparticle synthesis for biomedical applications.

Multifunctional Magnetic Nanocomposites: Innovative Processing and Applications

Multifunctional magnetic nanocomposites are among those heterogeneous nanosized systems where at least one phase component is magnetic and can act as an intermediate of either the actuation or the response of the overall system. The main advantage of heterogeneous nanosystems is the possibility of combining and inter-influencing the electronic properties of constituent interfaced nanophases. Consequently, unique physico-chemical properties of the hybrid materials of interest in various applications can be obtained. This Special Issue of Nanomaterials highlights the most advanced processing and characterization tools of some multifunctional magnetic nanocomposites and heterogeneous systems of interest in various applications, from biomedicine to sensoristics and energy-saving materials.

Biologic Impact of Green Synthetized Magnetic Iron Oxide Nanoparticles on Two Different Lung Tumorigenic Monolayers and a 3D Normal Bronchial Model-EpiAirwayTM Microtissue

The present study reports the successful synthesis of biocompatible magnetic iron oxide nanoparticles (MNPs) by an ecofriendly single step method, using two ethanolic extracts based on leaves of Camellia sinensis L. and Ocimum basilicum L. The effect of both green raw materials as reducing and capping agents was taken into account for the development of MNPs, as well as the reaction synthesis temperature (25 °C and 80 °C). The biological effect of the MNPs obtained from Camellia sinensis L. ethanolic extract (Cs 25, Cs 80) was compared with that of the MNPs obtained from Ocimum basilicum L. ethanolic extract (Ob 25, Ob 80), by using two morphologically different lung cancer cell lines (A549 and NCI-H460); the results showed that the higher cell viability impairment was manifested by A549 cells after exposure to MNPs obtained from Ocimum basilicum L. ethanolic extract (Ob 25, Ob 80). Regarding the biosafety profile of the MNPs, it was shown that the EpiAirway^TM models did not elicit important viability decrease or significant histopathological changes after treatment with none of the MNPs (Cs 25, Cs 80 and Ob 25, Ob 80), at concentrations up to 500 µg/mL.

Ag-Decorated Iron Oxides-Silica Magnetic Nanocomposites with Antimicrobial and Photocatalytic Activity

Nanotechnology offers unlimited possibilities for creating effective hybrid materials, which combine functional performance in environment depollution and antimicrobial defense with a lack of toxicity, biocompatibility, biodegradability, and natural availability. This paper presents the silver effect on photocatalytic and antibacterial activities of double-coated iron oxide nanoparticles (NPs), Fe3O4@SiO2/ZnO-Ag. The structural, morphological, and textural information of the, core-shell iron oxides-based superparamagnetic nanoparticles (IOMNPs) decorated with 5% Ag by ultrasound-assisted synthesis were evaluated by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDX), X-ray diffraction, Raman spectroscopy, and Brunauer-Emmett-Teller physisorption measurements. Although two synthesis temperatures of 95 and 80 °C were used for the co-precipitated iron oxide cores, the XRD patterns revealed the formation of a single magnetite, Fe3O4, phase. The sorption-photocatalytic activities under dark and UV irradiation encountered a maximum removal efficiency of the MB (90.47%) for the Fe3O4@SiO2/ZnO-Ag sample with iron oxide core obtained at 80 °C. The rate constant for the second-order kinetics was 0.0711 min-1 for 2 h, and the correlation coefficient R2 closed to unity. Two samples with Ag-decorated hybrid SiO2/ZnO shell and hierarchically interconnected porous structure with large surface area (328.8 and 342.5 m2g-1) exhibited the best disk diffusion antimicrobial activity against four microorganisms, especially gram-positive Staphylococcus aureus.

Role of Iron Oxide (Fe2O3) Nanocomposites in Advanced Biomedical Applications: A State-of-the-Art Review

Nanomaterials have demonstrated a wide range of applications and recently, novel biomedical studies are devoted to improving the functionality and effectivity of traditional and unmodified systems, either drug carriers and common scaffolds for tissue engineering or advanced hydrogels for wound healing purposes. In this regard, metal oxide nanoparticles show great potential as versatile tools in biomedical science. In particular, iron oxide nanoparticles with different shape and sizes hold outstanding physiochemical characteristics, such as high specific area and porous structure that make them idoneous nanomaterials to be used in diverse aspects of medicine and biological systems. Moreover, due to the high thermal stability and mechanical strength of Fe₂O₃, they have been combined with several polymers and employed for various nano-treatments for specific human diseases. This review is focused on summarizing the applications of Fe₂O₃-based nanocomposites in the biomedical field, including nanocarriers for drug delivery, tissue engineering, and wound healing. Additionally, their structure, magnetic properties, biocompatibility, and toxicity will be discussed.

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 Nanoparticles: Current Advances in Nanomedicine, Drug Delivery and MRI

Magnetic nanoparticles (MNPs) have evolved tremendously during recent years, in part due to the rapid expansion of nanotechnology and to their active magnetic core with a high surface-to-volume ratio, while their surface functionalization opened the door to a plethora of drug, gene and bioactive molecule immobilization. Taming the high reactivity of the magnetic core was achieved by various functionalization techniques, producing MNPs tailored for the diagnosis and treatment of cardiovascular or neurological disease, tumors and cancer. Superparamagnetic iron oxide nanoparticles (SPIONs) are established at the core of drug-delivery systems and could act as efficient agents for MFH (magnetic fluid hyperthermia). Depending on the functionalization molecule and intrinsic morphological features, MNPs now cover a broad scope which the current review aims to overview. Considering the exponential expansion of the field, the current review will be limited to roughly the past three years.

Microenvironmental Behaviour of Nanotheranostic Systems for Controlled Oxidative Stress and Cancer Treatment

The development of smart, efficient and multifunctional material systems for diseases treatment are imperative to meet current and future health challenges. Nanomaterials with theranostic properties have offered a cost effective and efficient solution for disease treatment, particularly, metal/oxide based nanotheranostic systems already offering therapeutic and imaging capabilities for cancer treatment. Nanoparticles can selectively generate/scavenge ROS through intrinsic or external stimuli to augment/diminish oxidative stress. An efficient treatment requires higher oxidative stress/toxicity in malignant disease, with a minimal level in surrounding normal cells. The size, shape and surface properties of nanoparticles are critical parameters for achieving a theranostic function in the microenvironment. In the last decade, different strategies for the synthesis of biocompatible theranostic nanostructures have been introduced. The exhibition of therapeutics properties such as selective reactive oxygen species (ROS) scavenging, hyperthermia, antibacterial, antiviral, and imaging capabilities such as MRI, CT and fluorescence activity have been reported in a variety of developed nanosystems to combat cancer, neurodegenerative and emerging infectious diseases. In this review article, theranostic in vitro behaviour in relation to the size, shape and synthesis methods of widely researched and developed nanosystems (Au, Ag, MnOx, iron oxide, maghemite quantum flakes, La2O3-x, TaOx, cerium nanodots, ITO, MgO1-x) are presented. In particular, ROS-based properties of the nanostructures in the microenvironment for cancer therapy are discussed. The provided overview of the biological behaviour of reported metal-based nanostructures will help to conceptualise novel designs and synthesis strategies for the development of advanced nanotheranostic systems.