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Carbon-encapsulated iron nanoparticles (Fe@C) with a mean diameter of 15 nm have been synthesized using evaporation–condensation flow–levitation method by the direct iron-carbon gas-phase reaction at high temperatures. Further, Fe@C were stabilized with bovine serum albumin (BSA) coating, and their electromagnetic properties were evaluated to test their performance in magnetic hyperthermia therapy (MHT) through a specific absorption rate (SAR). Heat generation was observed at different Fe@C concentrations (1, 2.5, and 5 mg/mL) when applied 331 kHz and 60 kA/m of an alternating magnetic field, resulting in SAR values of 437.64, 129.36, and 50.4 W/g for each concentration, respectively. Having such high SAR values at low concentrations, obtained material is ideal for use in MHT.

Smart biocompatible materials that respond to a variety of external stimuli have a lot of potential in the creation of low-cost diagnostic biosensors. The present work describes the creation of core–shell nanoparticles as a biosensor for smart enzyme detection of salivary alpha-amylase (sAA). A chitosan-tripolyphosphate core was generated via ionic gelation and was coated with a starch–iodine shell to create biocompatible core–shell nanoparticles. The starch–iodine shell was ruptured in the presence of certain amounts of amylase, exposing the core. This application explains a noticeable color change from blue to white that can be used to identify sAA at the point of care. Synthesized nanoparticles were examined for scanning electron microscopy analysis and energy-dispersive X-ray (EDX). An EDX report reveals that the nanoparticles have higher carbon content at 55% followed by an oxygen atom of 35%. Fourier-transform infrared spectroscopic analysis revealed that the core–shell nanoparticles have carbonyl (C═O) functional groups present. A confirmatory test of amylase reaction on nanoparticle-impregnated paper turns blue to white indicating that the nanoparticle reacts with amylase as an indicator. This paper-based method can be used in future applications in forensic and medical applications.

Background Although accumulating evidence suggests that the crosstalk between malignant cells and cancer-associated fibroblasts (CAFs) actively contributes to tumour growth and metastatic dissemination, therapeutic strategies targeting tumour stroma are still not common in the clinical practice. Metal-based nanomaterials have been shown to exert excellent cytotoxic and anti-cancerous activities, however, their effects on the reactive stroma have never been investigated in details. Thus, using feasible in vitro and in vivo systems to model tumour microenvironment, we tested whether the presence of gold, silver or gold-core silver-shell nanoparticles exerts anti-tumour and metastasis suppressing activities by influencing the tumour-supporting activity of stromal fibroblasts. Results We found that the presence of gold-core silver-shell hybrid nanomaterials in the tumour microenvironment attenuated the tumour cell-promoting behaviour of CAFs, and this phenomenon led to a prominent attenuation of metastatic dissemination in vivo as well. Mechanistically, transcriptome analysis on tumour-promoting CAFs revealed that silver-based nanomaterials trigger expressional changes in genes related to cancer invasion and tumour metastasis. Conclusions Here we report that metal nanoparticles can influence the cancer-promoting activity of tumour stroma by affecting the gene expressional and secretory profiles of stromal fibroblasts and thereby altering their intrinsic crosstalk with malignant cells. This potential of metal nanomaterials should be exploited in multimodal treatment approaches and translated into improved therapeutic outcomes.

A nanocomposite composed of carboxymethyl cellulose (CMC) and core–shell nanoparticles of Fe3O4@SiO2 was prepared as a pH-responsive nanocarrier for quercetin (QC) delivery. The nanoparticles were further entrapped in a water-in-oil-in-water emulsion system for a sustained release profile. The CMC/Fe3O4@SiO2/QC nanoparticles were characterized using dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), a field emission scanning electron microscope (FE-SEM), and a vibrating sample magnetometer (VSM) to obtain insights into their size, stability, functional groups/chemical bonds, crystalline structure, morphology, and magnetic properties, respectively. The entrapment and loading efficiency were slightly improved after the incorporation of Fe3O4@SiO2 NPs within the hydrogel network. The dialysis method was applied for drug release studies. It was found that the amount of QC released increased with the decrease in pH from 7.4 to 5.4, while the sustained-release pattern was preserved. The A549 cell line was chosen to assess the anticancer activity of the CMC/Fe3O4@SiO2/QC nanoemulsion and its components for lung cancer treatment via an MTT assay. The L929 cell line was used in the MTT assay to determine the possible side effects of the nanoemulsion. Moreover, a flow cytometry test was performed to measure the level of apoptosis and necrosis. Based on the obtained results, CMC/Fe3O4@SiO2 can be regarded as a novel promising system for cancer therapy.

Fe 3 O 4 @MoS 2 core–shell nanoparticles have a wide range of potential uses in the field of biomedicine, including drug delivery, target therapies, and NIR-stimulated tumor therapy. Whenever using the risk-free nanosystem, it is very important to manufacture and cover core–shell Fe 3 O 4 @MoS 2 nanoparticles with a biodegradable substance. In the present research, Fe 3 O 4 @MoS 2 core–shell nanoparticles were green synthesized by applying Allium hooshidaryae plant extracted as a reducing and stabilizing agent and then coated with chitosan. Synthesized nanoparticles were characterized by several structural and physical techniques, like scanning electron microscope (SEM), transmission electron microscope (TEM), vibrating-sample magnetometer (VSM), X-ray powder diffraction (XRD), and fourier-transform infrared spectroscopy (FTIR). The MTT test and an in vitro antimicrobial assay were used to examine the biological properties of the final nanoparticles. SEM and TEM results revealed uniform distribution of spherical Fe 3 O 4 NPs with the average size of 35.7 nm. Furthermore, TEM image revealed that the mean diameter of Fe 3 O 4 @MoS 2 core–shell NPs was approximately 52.7 nm that the Fe 3 O 4 NPs were surrounded by MoS 2 nanosheet layers. Chitosan-coated green-synthesized Fe 3 O 4 @MoS 2 core–shell nanoparticles exhibited promising anti-cancer properties against the MCF-7 cell line with an IC 50 value of ~ 50.83% reduction at 1000 μg/mL in cell viability as well as good antibacterial capabilities of MBC 500 µg/mL and MBC 250 µg/mL against Staphylococcus aureus and Pseudomonas aeruginosa , respectively. As a result, the synthesized nanoparticles have the potential to have useful benefits in future nanomedicine.

Metal matrix composites (MMCs) are a constantly developing class of materials. Simultaneously achieving a high strength and a high ductility is a challenging task in the design of MMCs. This article aims to highlight a recent trend: the development of MMCs reinforced with particles of core–shell structure. The core–shell particles can be synthesized in situ upon a partial transformation of metal (alloy) particles introduced into a metal matrix. MMCs containing core–shell particles with cores of different compositions (metallic, intermetallic, glassy alloy, high-entropy alloy, metal-ceramic) are currently studied. For metal core–intermetallic shell particle-reinforced composites, the property gain by the core–shell approach is strengthening achieved without a loss in ductility. The propagation of cracks formed in the brittle intermetallic shell is hindered by both the metal matrix and the metal core, which constitutes a key advantage of the metal core–intermetallic shell particles over monolithic particles of intermetallic compounds for reinforcing purposes. The challenges of making a direct comparison between the core–shell particle-reinforced MMCs and MMCs of other microstructures and future research directions are discussed.

The purpose of this study is to develop modified particles with different structures to improve the flowability and compactibility of Liuwei Dihuang (LWDH) powder using co-spray drying technology, and to investigate the preparation mechanism of modified particles and their modified direct compaction (DC) properties. Moreover, tablets with high drug loading contents were also prepared. Particles were designed using polyvinylpyrrolidone (PVP K30) and hydroxypropyl methylcellulose (HPMC E3) as shell materials, and sodium bicarbonate (NaHCO 3 ) and ammonium bicarbonate (NH 4 HCO 3 ) as pore-forming agents. The porous particles (Ps), core-shell particles (CPs), and porous core-shell particles (PCPs) were prepared by co-spray drying technology. The key DC properties and texture properties of all the particles were measured and compared. The properties of co-spray drying liquid were also determined and analyzed. According to the results, Ps showed the least improvement in DC properties, followed by CPs, and PCPs showed a significant improvement. The modifier, because of its low surface tension, was wrapped in the outer layer to form a shell, and the pore-forming agent was thermally decomposed to produce pores, forming core-shell, porous, and porous core-shell composite structures. The smooth surface of the shell structure enhances fluidity, while the porous structure allows for greater compaction space, thereby improving DC properties during the compaction process. Graphical Abstract

Improving novel and efficient biosensors for determining organic/inorganic compounds is a challenge in analytical chemistry for clinical diagnosis and research in biomedical sciences. Electrochemical enzyme-based biosensors are one of the commercially successful groups of biosensors that make them highly appealing because of their low cost, high selectivity, and sensitivity. Core/shell nanoparticles have emerged as versatile platforms for developing enzyme-based electrochemical biosensors due to their unique physicochemical properties and tunable surface characteristics. This study provides a comprehensive review of recent trends and advancements in the utilization of core/shell nanoparticles for the development of enzyme-based electrochemical biosensors. Moreover, a statistical evaluation of the studies carried out in this field between 2007 and 2023 is made according to the preferred electrochemical techniques. The recent applications of core/shell nanoparticles in enzyme-based electrochemical biosensors were summarized to quantify environmental pollutants, food contaminants, and clinical biomarkers. Additionally, the review highlights recent innovations and strategies to improve the performance of enzyme-based electrochemical biosensors using core/shell nanoparticles. These include the integration of nanomaterials with specific functions such as hydrophilic character, chemical and thermal stability, conductivity, biocompatibility, and catalytic activity, as well as the development of new hybrid nanostructures and multifunctional nanocomposites. Graphical Abstract

Background: Brain tumors are the most common tumors among adolescents. Although some chemotherapeutics are known to be effective against brain tumors based on cell culture studies, the same effect is not observed in clinical trials. For this reason, the development of drug delivery systems is important to treat brain tumors and prevent tumor recurrence. The aim of this study was to develop core–shell polymeric nanoparticles with positive charge by employing a chitosan coating. Additionally, an implantable formulation for the chemotherapeutic nanoparticles was developed as a bioadhesive film to be applied at the tumor site following surgical operation for brain glioma treatment. To obtain positively charged, implantable nanoparticles, the effects of preparation technique, chitosan coating concentration and presence of surfactants were evaluated to obtain optimal nanoparticles with a diameter of less than 100 nm and a net positive surface charge to facilitate cellular internalization of drug-loaded nanoparticles. Hydroxypropyl cellulose films were prepared to incorporate these nanoparticle dispersions to complete the implantable drug delivery system. Results: The diameter of core–shell nanoparticles were in the range of 70–270 nm, depending on the preparation technique, polymer type and coating. Moreover, the chitosan coating significantly altered the surface charge of the nanoparticles to net positive values of +30 to +50 mV. The model drug docetaxel was successfully loaded into all particles, and the drug release rate from the nanoparticles was slowed down to 48 h by dispersing the nanoparticles in a hydroxypropyl cellulose film. Cell culture studies revealed that docetaxel-loaded nanoparticles cause higher cytotoxicity compared to the free docetaxel solution in DMSO. Conclusion: Docetaxel-loaded nanoparticles dispersed in a bioadhesive film were shown to be suitable for application of chemotherapeutics directly to the action site during surgical operation. The system was found to release chemotherapeutics for several days at the tumor site and neighboring tissue. This can be suggested to result in a more effective brain tumor treatment when compared to chemotherapeutics administered as an intravenous bolus infusion.

Nanoparticles composed of metallic cores encapsulated in oxide shells emerged in the last decade as an attractive class of nanocomposite materials due to their high stability and unique properties provided by the high contact area between the metal and oxide components. Diverse metal-oxide interactions in metal@oxide core@shell nanoparticles enable tuning their electronic structure, spectroscopic properties, and surface reactivity for applications in sensing, electrochemistry, batteries as well as thermal and photocatalysis. Herein, we review the recent literature on the synthesis, characterization, simulations, and applications of metal@oxide nanocomposites. In particular, we discuss how the properties of metal@oxide nanoparticles can be tuned for a given application by changing the size of the metal core, the thickness and porosity of the oxide shell, as well as their composition, e.g. by alloying the core or doping the shell. Understanding of structure-property relations in metal@oxide systems provides vast opportunities for the rational design of advanced metal@oxide nanocomposites, making this class of materials promising for a wide range of applications.