Search Results (79)

Magnetic nanoparticles represent the next-generation drug delivery systems, enabling drug targeting to specific organs without adverse effects on the body and with a controlled release rate. Their strengths are represented by biocompatibility, low cost, and easy drug loading; some drawbacks are aggregation and poor stability in biological media. In the present work, we synthesized magnetic core–shell structures with a magnetite core coated with layered double hydroxides (LDHs) based on Mg²⁺ or Zn²⁺ and Al³⁺ ions and loaded with meloxicam, a poorly water-soluble anti-inflammatory drug. Several syntheses have been attempted to obtain iron oxides based on the only magnetite phase. The combined use of different characterization techniques allowed us to reveal that the best product, showing the crucial room temperature superparamagnetism and a good level of compositional uniformity, was obtained from co-precipitation in nitrogen flow. The next LDH coating was successful, even if the hybrids showed the occurrence of aggregation. The drug was mainly adsorbed onto the LDH surfaces, as shown by the X-ray diffraction and Infrared Spectroscopy techniques. The loaded meloxicam amount was low, but the subsequent release into simulated body fluid could be prolonged for 4 days. Our study provides a proof of concept about the importance of a thorough characterization of the nanocomposite hybrids and their possible use for tricky drugs, such as those of class II of the Biopharmaceutical Classification System. Full article

Background/Objectives: Magnetite nanoparticles represent promising candidates for a broad spectrum of biomedical applications, ranging from in vitro diagnostic assays to in vivo imaging, hyperthermia, and targeted drug and gene delivery, with some nanoagents already approved for clinical use. A critical determinant of their functionality is the nanoparticle coating, which facilitates beneficial interactions within biological systems. In the context of tumor-targeted therapeutic delivery, key design parameters—particularly surface coatings—can be optimized to enhance treatment efficacy by modulating blood circulation kinetics, biodistribution, and other critical properties. However, current preclinical screening methods primarily rely on cell culture models to identify potential nanocarriers, yet these systems often poorly correlate with actual in vivo performance. This discrepancy highlights the necessity of incorporating more biologically relevant testing platforms, such as high-throughput in vivo assays. Methods: In this work, we employed an original magnetic particle quantification (MPQ) technology to systematically evaluate the blood circulation kinetics and biodistribution patterns for magnetite nanoparticles with 17 different coatings across multiple organs and tissues, including the liver, spleen, lungs, kidneys, heart, tumor, brain, peripheral blood, muscle, and bone. This methodology offers high sensitivity, user-friendly operation, and provides quantitative measurements across a broad dynamic range of nanoparticle concentrations. These advantages enabled high-throughput acquisition of precise blood circulation and biodistribution data. In addition, histological analysis was conducted to evaluate nanoparticle penetration depth within tumor tissue. Results: Here we conducted a comprehensive study of the effect of 17 different polymer-, lectin-, and small molecule-based coatings on the behavior of magnetite nanoparticles in vivo. For each type of obtained nanoparticles, we implemented passive targeting as well as magnetic targeting, the latter using an external magnetic field localized in the tumor area. Conclusions: The collected dataset provides critical insights into how surface modifications influence nanoparticle performance in complex biological systems, offering valuable guidance for optimizing therapeutic nanocarrier design. Full article

Regrettably, glioblastoma multiforme (GBM) remains the deadliest form of brain cancer, with a very unfavorable prognosis for life expectancy for the patient. We report, for the first time, the green colloidal synthesis of cobalt-doped magnetic iron oxide nanoparticles (Co-MNPs) as aqueous ferrofluids, using two anionic polysaccharide biopolymers, hyaluronic acid (HA) and carboxymethyl cellulose (CMC), as surfactants. These ferrofluids based on magnetite nanoparticles (HA@Co-MNP and CMC@Co-MNP) demonstrated superparamagnetic properties and magnetic-to-thermal conversion upon exposure to an alternating magnetic field (AMF), with the extent of conversion dependent on surfactant type. In addition, the ferrophase acted as a nanozyme, mimicking peroxidase-like activity in response to hydrogen peroxide, which is present at higher levels in tumor cells. The coupling of magnetic-heat capabilities with biocatalytic behavior enhances glioblastoma cell elimination and suppresses 3D neurospheroid growth. The results also showed that active targeting based on the HA biopolymer shell, due to its affinity for CD44 membrane receptors overexpressed in GBM, outperformed CMC-coated ferrofluid analogs. These magnetocatalytic-responsive nanoplatforms offer a broad avenue for the diagnosis and therapy of numerous cancers, potentially improving patients’ quality of life and prognoses. Full article

Nowadays, utilizing biodegradable and bio-inspired substances and combining them in innovative ways is a prerequisite for obtaining new and useful materials. In this paper, we designed and characterized eco-friendly materials as alternatives for packaging and medical applications. Thus, cellulose fibers of medical gauze or filter paper were coated with a mixed solution containing poly(vinyl alcohol) (PVA), plant-based synthesized silver particles (AgPs), and magnetite (MG). The composites and their components were studied using UV-Vis, FTIR, and Energy-Dispersive X-ray (EDX) spectroscopy, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) to evidence the presence, size, surface charge, morphology, and chemical composition of particles in the composites, as well as particle interactions. Their proven hydrophobic and antibacterial character could recommend them for the design of antifouling medical coatings and food packaging. Full article

Carbon-based nanocomposites coated with iron oxides were synthesized using a wet impregnation method with thermally annealed coal and an iron nitrate precursor. The influence of the thermal treatment atmosphere (air, vacuum, or nitrogen) on the morphology, structure, and magnetic properties of the nanocomposites was examined by X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. It was found that the vacuum thermal treatment produced carbon-based nanocomposite containing iron oxide with the highest crystallinity, according to XRD analysis, while also inducing the greatest degree of structural defects in the carbon matrix, as evidenced by Raman analysis. Mössbauer spectroscopy confirmed that all thermal treatment methods promote the formation of the hematite phase, which was found to be the only phase formed in the air-treated nanocomposites, whereas traces of magnetite and the formation of Fe(OH)₃ were detected in the vacuum- and nitrogen-treated nanocomposites, respectively. Magnetic characterization revealed that all nanocomposites exhibit ferromagnetic-like behavior, attributed to the weak ferromagnetic nature of hematite. The best magnetic response (highest saturation magnetization with the widest hysteresis loop) was observed in the vacuum-treated nanocomposites. These findings collectively demonstrate that the synthesis atmosphere plays a crucial role in tailoring the structural and magnetic characteristics of carbon-based iron oxide nanocomposites, offering pathways for their optimization in applications such as catalysis, environmental remediation, or sensing technologies. Full article

Background/Objectives: Gamma irradiation is a promising terminal sterilization method for nanoparticle-based biomedical systems. However, its potential effects on the physicochemical properties and biological performance of multifunctional nanomaterials must be carefully evaluated. This study aimed to assess the structural integrity, sterility, and cytocompatibility of magnetic nanoparticles (MNPs) and bioactive-glass-coated magnetic nanoparticles (MNPBGs), both based on magnetite (Fe₃O₄), after gamma irradiation. Methods: MNPs and MNPBGs were synthesized and subjected to gamma irradiation at 25 kGy, with additional doses explored in preliminary evaluations. Physicochemical characterizations were performed using XRD, TEM, SAED, and Raman spectroscopy. FTIR analyses were conducted on bioactive glass (BG) controls without magnetite. Sterility was evaluated via microbiological assays. Cytocompatibility and nitric oxide (NO) production were assessed using RAW 264.7 macrophages and Saos-2 osteosarcoma cells. Prussian blue staining was used to evaluate cellular uptake. Results: Gamma irradiation preserved the crystal structure, morphology, and size distribution of the nanoparticles. FTIR revealed only minor changes in the silicate network of BG, such as reduced intensity and slight shifting of Si-O-Si and Si-O-NBO bands, indicating limited radiation-induced structural rearrangement without affecting the material’s stability or cytocompatibility. Microbiological assays confirmed complete inhibition of microbial growth. All irradiated samples exhibited high cytocompatibility, with MNPBGs demonstrating enhanced biological responses. Notably, MNPBGs induced a more pronounced NO production in macrophages. Cellular uptake of nanoparticles by Saos-2 cells remained unaffected after irradiation. Conclusions: Gamma irradiation at 25 kGy is an effective sterilization strategy that maintains the structural and functional integrity of MNPs and MNPBGs. These findings support their safe use in sterile biomedical applications, particularly for bone-related therapies involving immunomodulation and drug delivery, with potential relevance for cancer treatment strategies such as osteosarcoma. Full article

This study provides a comparison between magnetic-to-thermal energy conversion efficiency in liquid and gel phases under high-frequency magnetic fields. Magnetite cores (11 ± 2 nm) were tested as water-based ferrofluids and as 5 wt% agar ferrogels, both with and without a biocompatible polydopamine (PDA) shell. A custom two-phase coil switched between rotating (RMF) and alternating (AMF) modes, enabling phase- and coating-dependent effects to be measured at identical field strengths and frequencies (100–300 kHz, 1–4 kA/m). Across all conditions, RMF generated 1.7–2.1 times more specific loss power (SLP) than AMF, and moving from the liquid to the gel phase reduced SLP by 5–8%, indicating that heating is controlled by Néel relaxation with negligible Brownian contribution. SLP rose with magnetic-field amplitude according to a power law, while hysteretic losses remained minimal. PDA improved colloidal stability and biocompatibility without harming the heating performance, lowering SLP by <17%. Within Brezovich limits, the system still exceeded therapeutic hyperthermia thresholds. Thus, in this iron-oxide/PDA system, neither medium viscosity nor the PDA shell’s non-magnetic mass significantly affects thermal energy output, an important finding for translating laboratory calorimetry data into reliable, application-oriented modelling for magnetic hyperthermia. Full article

The high incidence of melanoma leading to a poor prognosis rate endorses the development of alternative and innovative approaches in the treatment of melanoma. Therefore, the present study aims to develop and characterize, in terms of physicochemical features and biological impact, an aqueous suspension of magnetite (Fe₃O₄) coated with β-cyclodextrin (Fe₃O₄@β-CD) as a potential innovative alternative nanosystem for melanoma therapy. The nanosystem exhibited physicochemical characteristics suitable for biological applications, revealing a successful complexation of Fe₃O₄ NPs with β-CD and an average size of 18.1 ± 2.1 nm. In addition, the in vitro evaluations revealed that the newly developed nanosystem presented high biocompatibility on a human keratinocyte (HaCaT) monolayer and selective antiproliferative activity on amelanotic human melanoma (A375) cells, inducing early apoptosis features when concentrations of 10, 15, and 20 μg/mL were employed for 48 h and 72 h. Collectively, the Fe₃O₄@β-CD nanosystem reveals promising features for an adjuvant approach in melanoma treatment, mainly due to its β-cyclodextrin coating, thus endorsing a potential co-loading of therapeutic drugs. Furthermore, the intrinsic magnetic core of Fe₃O₄ NPs supports the magnetically based cancer treatment strategies. Full article

Background/Objectives: Magnetic nanoparticles, particularly iron oxide-based materials, such as magnetite (Fe₃O₄), have gained significant attention as contrast agents in medical imaging This study aimsto syntheze and characterize Fe₃O₄-based core–shell nanostructures, including Fe₃O₄@TiO₂ and Fe₃O₄@SiO₂, and to evaluate their potential as tunable contrast agents for diagnostic imaging. Methods: Fe₃O₄, Fe₃O₄@TiO₂, and Fe₃O₄@SiO₂ nanoparticles were synthesized via co-precipitation at varying temperatures from iron salt precursors. Fourier transform infrared spectroscopy (FTIR) was used to confirm the presence of Fe–O bonds, while X-ray diffraction (XRD) was employed to determine the crystalline phases and estimate average crystallite sizes. Morphological analysis and particle size distribution were assessed by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and transmission electron microscopy (TEM). Magnetic properties were investigated using vibrating sample magnetometry (VSM). Results: FTIR spectra exhibited characteristic Fe–O vibrations at 543 cm⁻¹ and 555 cm⁻¹, indicating the formation of magnetite. XRD patterns confirmed a dominant cubic magnetite phase, with the presence of rutile TiO₂ and stishovite SiO₂ in the coated samples. The average crystallite sizes ranged from 24 to 95 nm. SEM and TEM analyses revealed particle sizes between 5 and 150 nm with well-defined core–shell morphologies. VSM measurements showed saturation magnetization (Ms) values ranging from 40 to 70 emu/g, depending on the synthesis temperature and shell composition. The highest Ms value was obtained for uncoated Fe₃O₄ synthesized at 94 °C. Conclusions: The synthesized Fe₃O₄-based core–shell nanomaterials exhibit desirable structural, morphological, and magnetic properties for use as contrast agents. Their tunable magnetic response and nanoscale dimensions make them promising candidates for advanced diagnostic imaging applications. Full article

Glutamate, the primary excitatory neurotransmitter in the central nervous system, plays a pivotal role in synaptic signaling, learning, and memory. Abnormal glutamate levels are implicated in various neurological disorders, including epilepsy, Alzheimer’s disease, and ischemic stroke. Despite the utility of magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) in diagnosing such conditions, the development of effective glutamate-sensitive contrast agents remains a challenge. In this study, we present ultrasmall, citric acid-coated superparamagnetic iron oxide nanoparticles (CA-SPIONs) as highly selective and sensitive MRS probes for glutamate detection. These 5 nm magnetite CA-SPIONs exhibit a stable dispersion in physiological buffers and undergo aggregation in the presence of glutamate, significantly enhancing the T₂ MRS contrast power. At physiological glutamate levels, the CA-SPIONs yielded a pronounced signal change ratio of nearly 60%, while showing a negligible response to other neurotransmitters such as GABA and dopamine. Computational simulations confirmed the mechanism of glutamate-mediated aggregation and its impact on transversal relaxation rates and relaxivities. The sensitivity and selectivity of CA-SPIONs underscore their potential as eco-friendly, iron-based alternatives for future neurological sensing applications targeting glutamatergic dysfunction. Full article

This review analyzes the use of magnetite-based catalysts in various oxidation reactions. It is shown that magnetite-based catalysts are the most promising candidates from the standpoint of easy separation from the reaction zone and reusability. Diverse examples of the use of magnetite-based composites are discussed, including the following reactions: partial oxidation of methane to formaldehyde; the oxidation of cycloalkanes into alcohols and ketones; the oxidation of alkenes and alcohols with the major focus made on benzylic alcohol oxidation; oxidative cracking of alkenes; Fenton-type reactions with H₂O₂ as a benign oxidant; the removal of dyestuff in water (including wastewater by oxidation); reactions of sulfides and thiols; the oxidation of 5-hydroxymethylfurfural as a platform chemical to 2,5-diformylfuran; the oxidation of D-glucose to D-gluconic acid; and the electrocatalytic oxidation of methanol and ethanol. The most important and best-studied applications of magnetic nanoparticles in the oxidation reactions are believed to be the oxidation of diverse benzylic alcohols and D-glucose, and Fenton-like reactions aiming at the removal of S- and N-compounds from ware and fuels. Magnetic nanocomposites are determined as the materials meeting a range of criteria: (1) they should be magnetic, (2) they contain nanoparticles, and (3) they consist of two (or more) nanocomponents. The core–shell materials with magnetic nanoparticles used as a core or as decorating nanoparticles are discussed in the review. Three main types of magnetic nanocomposites can be distinguished: (1) the systems where the magnetic phase is active in the considered reaction, for instance, Fenton-like oxidation; (2) the systems containing active metal nanoparticles supported onto the magnetic nanoparticles; and (3) materials with magnetic nanoparticles as a core coated with one or two shells (porous or non-porous), with the magnetic nanoparticles being active or not in the title reaction. Magnetic nanoparticles exhibit a number of advantages compared with supported non-magnetic catalysts of oxidation reactions. The advantages include the possibility of separation from the reaction medium (5–10 times) without a significant loss of the activity, their non-toxicity, low cost, and availability, and the easy preparation of these materials. The drawbacks may include the leaching of active components; a decrease in saturation magnetization in comparison with the bulk magnetite; a limited accessibility of active sites due to diffusion through the shells; the complicated composition and structure of the nanomaterials; a decrease in the activity and specific surface area; and a limited number of magnetic compounds with acceptable characteristics. Nevertheless, the advantages of magnetic nanocatalysts stimulate their wide use in liquid-phase oxidation reactions, which will be discussed in the review. Future perspectives on the use of magnetic composites are considered. Full article

Magnetic fluid hyperthermia, a minimally invasive localized therapy that uses heat generated by magnetic nanoparticles under an AC magnetic field, is a complementary approach for cancer treatment that is excellent due to its advantages of being noninvasive and addressing only the affected region. Still, its use as a stand-alone therapy is hindered by the simultaneous requirement of nanoparticle biocompatibility, good heating efficiency, and physiological safe dose. To overcome these limits, the biocompatible magnetic nanoparticles’ heating efficiency must be optimized. Iron oxide nanoparticles are accepted as the more biocompatible magnetic nanoparticles available. Therefore, in this work, superparamagnetic iron oxide nanoparticles were synthesized by a low-cost coprecipitation method and modified with starch and gum to increase their heating efficiency and compatibility with living tissues. Two different reducing agents, sodium hydroxide (NaOH) and ammonium hydroxide (NH₄OH), were used to compare their influence. The X-ray diffraction results indicate the formation of a single magnetite/maghemite phase in all cases, with the particle size distribution depending on the coating and reducing agent. Citric acid functionalized water-based ferrofluids were also prepared to study the heating efficiency of the nanoparticles under a magnetic field with a 274 kHz frequency and a 14 kAm⁻¹ amplitude. The samples prepared with NaOH display a higher specific loss power (SLP) compared to the ones prepared with NH₄OH. The SLP value of 72 Wg⁻¹ for the magnetic nanoparticles coated with a combination of starch and gum arabic, corresponding to an intrinsic loss power (ILP) of 2.60 nWg⁻¹, indicates that they are potential materials for magnetic hyperthermia therapy. Full article

Thiosemicarbazone (TSC) derivatives and their complexes have emerged as versatile medicinal agents. Now, the focus has shifted to targeted drug delivery and here, the application of nanotechnology is being explored. Nanoparticles (NP) are being explored owing to their tremendous medicinal applications. They are also known to overcome the water insolubility of medicinal agents and have the ability to target specific targets. This article aims to explore the fabrication strategies and applications of functionalized TSCs conjugated with NPs for improved therapeutic potential. The studies were taken from the recent literature and indexed in leading databases. The literature survey reveals the fabrication of TSCs with chitosan-coated superparamagnetic magnetite NPs, which showed significant anti-proliferative activity against several cell lines. Similarly, cobalt oxide nanoparticles conjugated with TSCs have been tested against the hepatic cancer cell line HepG2. Other than anticancer activity, the functionalized nanoparticles have also been employed against drug-resistant pathogens. To improve the oral bioavailability and pharmacological activity, nanoparticle-based block polymers have been proposed to encapsulate the TSC moiety. The in vitro activity of the fabricated NPs has been tested against Leishmania amazonensis. Against microphages, less cytotoxicity was observed. The article may shed light on the structure–bioactivity relationship of novel nanocomposites derived from TSCs and NPs and their specific mechanisms of action. Full article

Nanoparticles (NPs) are receiving increasing interest in biomedical applications. However, due to their large surface area, in physiological environments, they tend to interact with plasma proteins, inducing their agglomeration and ultimately resulting in a substantial efficiency decrease in diagnostic and therapeutic applications. To overcome such problems, NPs are typically coated with a layer of hydrophilic and biocompatible polymers, such as PEG chains. However, few examples exist in which this property could be systematically fine-tuned and combined with added properties, such as emission. Herein, we report a novel mussel-inspired catechol-based strategy to obtain biocompatible and multifunctional coatings, using a previously developed polymerization methodology based on the formation of disulfide bridges under mild oxidative conditions. Two families of NPs were selected as the proof of concept: mesoporous silica NPs (MSNPs), due to their stability and known applications, and magnetite NPs (Fe₃O₄ NPs), due to their small size (<10 nm) and magnetic properties. The PEG coating confers biocompatibility on the NPs and can be further functionalized with bioactive molecules, such as glucose units, through the end carboxylic acid moieties. Once we demonstrated the feasibility of our approach to obtaining PEG-based coatings on different families of NPs, we also obtained multifunctional coatings by incorporating fluorescein functionalities. The resulting coatings not only confer biocompatibility and excellent cell internalization, but also allow for the imaging and tracking of NPs within cells. Full article