Core-shell Nanomaterials Research Articles

An Overview of the Production of Magnetic Core-Shell Nanoparticles and Their Biomedical Applications

Several developments have recently emerged for core-shell magnetic nanomaterials, indicating that they are suitable materials for biomedical applications. Their usage in hyperthermia and drug delivery applications has escalated since the use of shell materials and has several beneficial effects for the treatment in question. The shell can protect the magnetic core from oxidation and provide biocompatibility for many materials. Yet, the synthesis of the core-shell materials is a multifaceted challenge as it involves several steps and parallel processes. Although reviews on magnetic core-shell nanoparticles exist, there is a lack of literature that compares the size and shape of magnetic core-shell nanomaterials synthesized via various methods. Therefore, this review outlines the primary synthetic routes for magnetic core-shell nanoparticles, along with the recent advances in magnetic core-shell nanomaterials. As core-shell nanoparticles have been proposed among others as therapeutic nanocarriers, their potential applications in hyperthermia drug delivery are discussed.

Describing a modern therapeutic drug prepared by in situ decorated gold nanoparticles on starch-modified magnetic nanoparticles to treat the cutaneous wound: a preclinical trial study

In recent days, the green synthesized nanomagnetic biocomposites have been evolved with tremendous potential as the future catalysts. This has encouraged us to design and synthesis of a novel Au NP fabricated starch functionalized core-shell type nanomaterial (Fe3O4/Starch-Au nanocomposite). It was meticulously characterized using advanced analytical techniques like FT-IR, FESEM, TEM, EDX, VSM, XRD and ICP-OES. MTT assay was used on common normal cell line i.e. Human umbilical vein endothelial cells (HUVEC) to survey the cytotoxicity effects of Fe3O4/Starch-Au nanocomposite. In the part of cutaneous wound healing, use of Fe3O4/Starch-Au nanocomposite ointment, significantly (p ≤ 0.01) raised the wound contracture, vessel, hydroxyl proline, hexuronic acid, fibrocyte, fibroblast, and fibrocytes/fibroblast rate and significantly (p ≤ 0.01) decreased the wound area, total cells, neutrophil, and lymphocyte compared to other groups in rats. Finally, the results showed the useful cutaneous wound healing properties of Fe3O4/Starch-Au nanocomposite. Maybe significant cutaneous wound healing potentials of Fe3O4/Starch-Au nanocomposite are related to their antioxidant activities. For investigating the antioxidant activities of Fe3O4/Starch-Au nanocomposite, the DPPH test was used in the presence of butylated hydroxytoluene as the positive control. The Fe3O4/Starch-Au nanocomposite inhibited half of the DPPH molecules in the concentration of 156 µg/mL.

Development of core-shell nanomaterials for energy storage devices using chemical solution method

Professor Tomoya Ohno and Associate Professor Shigeto Hirai, Kitami Institute of Technology, Kitami, Japan, are collaborating on research on the composition and coating of catalysts used in rechargeable metal-air batteries. Ohno specialises in surface coatings and powder technology and Hirai is an expert in electro- and solid-state chemistry and so these combined specialisms lend themselves well to the work. The researchers are developing long-life, high-performance bi-functional catalyst particles that can be mounted on rechargeable metal-air batteries, and are also proposing positive particles coated with a solid electrolyte for use in all-solid state lithium-ion batteries. Due to the high density associated with the design of the metal-air battery, it has the potential to store a lot more energy than conventional batteries. This means that metal-air batteries could prove transformative for industry, with the potential to be used in electric cars, national grid energy storage and other devices that require regular charging. However, the technology of the metal-air battery is still in progress and key concerns are the reliability of the cathode as well as the harsh effects of charging at high cathodic potentials. Ohno and Hirai are working to overcome these challenges by using chemical reaction and powder engineering techniques to add thin films of protective materials for the potential catalysts that could help stabilise the cathode. So far, the researchers have found that the protective layer on the bi-functional catalyst particles that were mounted on the metal-air secondary battery significantly improved the stability. They also found that the effect varies depending on the structure of the coating layer.

Fluorophore Localization Determines the Results of Biodistribution of Core-Shell Nanocarriers.

IntroductionBiodistribution of nanocarriers with a structure consisting of core and shell is most often analyzed using methods based on labeling subsequent compartments of nanocarriers. This approach may have serious limitations due to the instability of such complex systems under in vivo conditions.MethodsThe core-shell polyelectrolyte nanocarriers were intravenously administered to healthy BALB/c mice with breast cancer. Next, biodistribution profiles and elimination routes were determined post mortem based on fluorescence measurements performed for isolated blood, tissue homogenates, collected urine, and feces.ResultsDespite the surface PEGylation with PLL-g-PEG, multilayer polyelectrolyte nanocarriers undergo rapid degradation after intravenous administration. This process releases the shell components but not free Rhodamine B. Elements of polyelectrolyte shells are removed by hepatobiliary and renal clearance.ConclusionMultilayer polyelectrolyte nanocarriers are prone to rapid degradation after intravenous administration. Fluorophore localization determines the obtained results of biodistribution and elimination routes of core-shell nanomaterials. Therefore, precise and reliable analysis of in vivo stability and biodistribution of nanomaterials composed of several compartments requires nanomaterials labeled within each compartment.

Orally administered Bi2S3@SiO2 core-shell nanomaterials as gastrointestinal contrast agents and their influence on gut microbiota.

Effective and safe contrast agents for X-ray computed tomography (CT) imaging of the gastrointestinal (GI) tract are quite desirable for realizing high diagnostic accuracy and low toxicity in the clinic. Herein, we synthesize a series of silica-coated bismuth sulfide core-shell nanomaterials (Bi2S3@SiO2) of various sizes and systematically study their GI CT contrast performance and potential toxic effects in comparison with those of barium sulfate (BaSO4) in mice. The in vivo experimental results suggest that these Bi2S3@SiO2 core-shell nanomaterials display superior CT contrast performance and higher elimination efficacy than BaSO4 by single-dose exposure manner (10​mg/kg Bi element/b.w. for Bi2S3@SiO2 versus 30​mg/kg Ba element/b.w. for BaSO4). Furthermore, 28 days after exposure, Bi2S3@SiO2 core-shell nanomaterials show minimal toxic effects in vivo and nonsignificant influences on the structure and function of the gut microbiota in mice. This demonstrates that no adverse effects on the gut homeostasis are induced by Bi2S3@SiO2 core-shell nanomaterials and, thus, suggests that they can act as excellent and safe CT contrast agents for GI tract imaging.

L-Asparagine-EDTA-amide silica-coated MNPs: a highly efficient and nano-ordered multifunctional core-shell organocatalyst for green synthesis of 3,4-dihydropyrimidin-2(1H)-one compounds.

In this study, new l-asparagine grafted on 3-aminopropyl-modified Fe3O4@SiO2 core–shell magnetic nanoparticles using the EDTA linker (Fe3O4@SiO2–APTS–EDTA–asparagine) was prepared and its structures properly confirmed using different spectroscopic, microscopic and magnetic methods or techniques including FT-IR, EDX, XRD, FESEM, TEM, TGA and VSM. The Fe3O4@SiO2–APTS–EDTA–asparagine core–shell nanomaterial was found, as a highly efficient multifunctional and recoverable organocatalyst, to promote the efficient synthesis of a wide range of biologically-active 3,4-dihydropyrimidin-2(1H)-one derivatives under solvent-free conditions. It was proved that Fe3O4@SiO2–APTS–EDTA–asparagine MNPs, as a catalyst having excellent thermal and magnetic stability, specific morphology and acidic sites with appropriate geometry, can activate the Biginelli reaction components. Moreover, the environmental-friendliness and nontoxic nature of the catalyst, cost effectiveness, low catalyst loading, easy separation of the catalyst from the reaction mixture and short reaction time are some of the remarkable advantages of this green protocol.

A rational design of copper-selenium nanoclusters that cures sepsis by consuming endogenous H2S to trigger photothermal therapy and ROS burst.

The treatment of sepsis caused by bacterial infections is still a huge clinical challenge. As sepsis causes high levels of endogenous H2S in vivo, researchers can design nanomedicines to treat sepsis by in situ sulfurization. Here, we designed and synthesized Cu2O-coated non-metallic core-shell selenium nanoparticles. To cure mice sepsis by ROS burst. Our experimental data displayed that the photothermal effect of Se@Cu9S8 produced by the reaction of Se@Cu2O and endogenous H2S is synergistically antibacterial, and Se@Cu2O has the characteristics of low side effects and high biocompatibility. In summary, our research results verified our design, that copper-selenium nanoclusters may be an efficient strategy to cure sepsis by in situ sulfurization of endogenous H2S, triggering ROS eruptions and photothermal therapy.

Structural Design for Controlling the Lattice Strain Relaxation Process in TiO2/SiO2 Core–Shell Nanoparticles

Substantial lattice strain arising from lattice misfit of the components of core–shell nanomaterials used to accommodate lanthanide emitters usually significantly results in an inhomogeneous shell,...

Unraveling the shell growth pathways of Pd-Pt core-shell nanocubes at atomic level by in situ liquid cell electron microscopy

Understanding the formation of core-shell nanomaterials is decisive for controlling their growth, structure, and morphology, which is particularly important in catalysis. As a promising material for photo catalysis application, Pd-Pt core-shell nanoparticles (NPs) have been in the spotlight for many years owing to their catalytic performance typically superior to that of pure Pt nanoparticles. The generation of ultra-thin Pt skins of only a few atomic layers on Pd nanoparticles has turned out to be extremely difficult because Pt tends to form islands during deposition instead of a continuous shell. Therefore, understanding the atomic mechanisms of shell formation is critical for atomic-scale design and control of the platinum shell. Here, by using in situ graphene-based liquid cell scanning transmission electron microscopy (STEM), the growth mechanisms of the Pt shell on Pd nanocubes (NCs) are studied in aqueous solution at the atomic level. Pd-Pt core-shell NPs are formed via two distinct mechanisms: (i) at low concentration of Pt atoms, an ultra-thin skin of only a few atomic layers is formed via atom-by-atom deposition and (ii) at higher concentration of Pt atoms, inhomogeneous islands and thick shells are formed via attachment of Pt clusters. Our study provides a route to control core-shell growth and helps us to understand the exact atomic mechanisms of Pt shell growth on Pd seeds.

Au@MnO Core-shell Nanomaterials for Tumor Diagnosis and Therapy

Spherical Au nanoparticles were synthesized by thermal decomposition at high temperature, then were coated with a layer of MnO to form Au@MnO core-shell nanomaterial. MRI results show that the paramagnetic MnO shell could accelerate the longitudinal relaxation of proton in water molecules, with magnetic resonance imaging diagnostic capability; photothermal conversion results indicated that Au core possessed obvious near-infrared absorption and good photothermal heating effect. The as-prepared Au@MnO core-shell nanomaterial was injected into mice through tail vein, and it was found that the magnetic resonance signal in tumor area enhanced significantly to 181%, which was obviously different with the surrounding normal tissues. Under 808 nm laser irradiation, tumor temperature increased rapidly to about 60℃. These results provided an experimental example of Au@MnO nanomaterial for tumor diagnosis and treatment.

Preparation and spectral properties of CuSe/ZnSe core-shell nanomaterials

In this research, first, CuSe nanoparticles (NPs) were synthesized by using the reflux condensation method. Then, a ZnSe shell was grown on the CuSe NPs by using a simple, rapid photochemical approach. Synthesized CuSe/ZnSe core-shell NPs were characterized by means of different analyses, such as X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV-visible (UV-Vis) spectroscopy and photoluminescence (PL) spectroscopy. The XRD analysis of the sample shows the formation of core-shell NPs with the structure of hexagonal CuSe and cubic ZnSe. The core-shell structure of the product has been formed and the size of the synthesized core-shell NPs is about 20–50 nm. The band gap of the CuSe/ZnSe core-shell NPs was higher than that for CuSe or ZnSe in bulk. The fluorescence properties were greatly enhanced by successful growth of the ZnSe shell and decreased with the extension of illumination time.

Potentialities of core@shell nanomaterials for biosensor technologies

This featured article is based on the author's experience and personal overview of the synthesis, characterization, high performances and ultra-responsive utilization of core@shell nanomaterials (CSNs) in the biosensing field. Over the last few years, biosensor-related research using CSNs has progressed significantly, but, recently, CSNs with specific shape and size-tunable dependent physical and chemical properties have been found to be utilized for fabrication of chemosensors and biosensors with substantial attention. Following that, nano and microsensors made from stable, susceptible CSNs are used in diagnostics, enzymatic glucose determination, electrochemical DNA biosensors to detect pathogenic bacteria, and integrated wearable healthcare electronics as sensors. Nowadays, the utilization of plasmonic CSNs as probes for the colorimetric detection of various analytes and antibody conjugated CSNs for naked-eye immunosensing have also received considerable importance. Hence, this featured article compiles the up-to-date data of the state-of-the-art development on CSNs based biosensors and discusses their future aspects and challenges.

Iron Oxide/Polymer Core-Shell Nanomaterials with Star-like Behavior.

Embedding nanoparticles (NPs) with organic shells is a way to control their aggregation behavior. Using polymers allows reaching relatively high shell thicknesses but suffers from the difficulty of obtaining regular hybrid objects at gram scale. Here, we describe a three-step synthesis in which multi-gram NP batches are first obtained by thermal decomposition, prior to their covalent grafting by an atom transfer radical polymerization (ATRP) initiator and to the controlled growing of the polymer shell. Specifically, non-aggregated iron oxide NPs with a core principally composed of γ-Fe2O3 (maghemite) and either polystyrene (PS) or polymethyl methacrylate (PMMA) shell were elaborated. The oxide cores of about 13 nm diameter were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). After the polymerization, the overall diameter reached 60 nm, as shown by small-angle neutron scattering (SANS). The behavior in solution as well as rheological properties in the molten state of the polymeric shell resemble those of star polymers. Strategies to further improve the screening of NP cores with the polymer shells are discussed.

Core-shell nanomaterials engineered to reverse cancer multidrug resistance by immunotherapy and promote photo-responsive chemotherapy

Cancer immunotherapy has already become a critical hallmark in clinical cancer therapy, especially through tumor associated macrophages (TAMs) polarization. Because multidrug resistance (MDR) hinders the efficiency of chemotherapy, immunotherapy was also incorporated in regulation of MDR. Herein, Au nanocages encapsulated with doxorubicin (Dox) by the phase change material were fabricated with a layer consisting of calcium and ferrous carbonates (FeCaC), and achieved DPAu@FeCaC NPs could reprogram TAMs from immunosuppressive M2 to immunostimulatory M1 based on the intrinsic property of FeCaC shell. Nitric oxide (NO) could be produced by M1 TAMs to inhibit P-glycoprotein (P-gp) expression. Then, FeCaC shell of DPAu@FeCaC NPs could be degraded at the acidic condition and NIR laser irradiation would further facilitate to thermally release Dox. A series of in vitro and in vivo assessments confirmed DPAu@FeCaC NPs could realize the immunotherapy-mediated highly efficient chemotherapy of MDR cancer.

Characterization and Cytotoxicity Comparison of Silver- and Silica-Based Nanostructures.

Core-shell structures are the most common type of composite material nanostructures due to their multifunctional properties. Silver nanoparticles show broad antimicrobial activity, but the safety of their utilization still remains an issue to tackle. In many applications, the silver core is coated with inorganic shell to reduce the metal toxicity. This article presents the synthesis of various materials based on silver and silica nanoparticles, including SiO2@Ag, Ag@SiO2, and sandwich nanostructures—Ag@SiO2@Ag—and the morphology of these nanomaterials based on transmission electron microscopy (TEM), UV-Vis spectroscopy, and FT-IR spectroscopy. Moreover, we conducted the angle measurements due to the strong relationship between the level of surface wettability and cell adhesion efficiency. The main aim of the study was to determine the cytotoxicity of the obtained materials against two types of human skin cells—keratinocytes (HaCaT) and fibroblasts (HDF). We found that among all the obtained structures, SiO2@Ag and Ag@SiO2 showed the lowest cell toxicity and very high half-maximal inhibitory concentration. Moreover, the measurements of the contact angle showed that Ag@SiO2 nanostructures were different from other materials due to their superhydrophilic nature. The novel approach presented here shows the promise of implementing core-shell type nanomaterials in skin-applied cosmetic or medical products.

Mesoporous Au@Cu2−xS Core–Shell Nanoparticles with Double Localized Surface Plasmon Resonance and Ligand Modulation for Hole‐Selective Passivation in Perovskite Solar Cells

Core–shell nanomaterials have led to their fascinating properties in optical applications due to the localized surface plasmon resonance (LSPR). Herein, a mesoporous core–shell Au@Cu2−x S nanomaterial with dual LSPR characteristics is introduced to stabilize and passivate the perovskite/spiro‐OMeTAD interface of perovskite solar cells (PSCs). Thanks to the LSPR, Au@Cu2−x S nanoparticles (NPs) have the potential to enhance the infrared absorption and intensify the local electric field at the perovskite/spiro‐OMeTAD interface. The embedding of the mesoporous Au@Cu2−x S in the spiro‐OMeTAD layer can improve the contact and form “bridges” between perovskite grains and spiro‐OMeTAD. With the help of cationic surfactant cetyltrimethylammonium bromide, these mesoporous Au@Cu2−x S NPs can passivate surface traps and smooth the valence‐band offset at the perovskite/spiro‐OMeTAD interface for hole transferring. Furthermore, the improved hole mobility can offer balanced charge transport and prevent the carrier accumulation at interfaces. As a result, the Au@Cu2−x S(20:10)‐based PSCs achieves a champion efficiency over 22%, higher than that of the Au@Cu2−x S‐based device.

Antimicrobial Activities of Single Nano particle (SNPs) & Core-shell Nanomaterials (CSNMs) with Special Reference to Binding Mechanisms

Antimicrobial Activities of Single Nano particle (SNPs) & Core-shell Nanomaterials (CSNMs) with Special Reference to Binding Mechanisms

Tuning the shell thickness of core-shell α-Fe2O3@SiO2 nanoparticles to promote microwave absorption

Various advanced microwave absorbing materials have been developed for reducing/avoiding the harm of microwave radiation. Among them, core-shell structural nanomaterials have been widely fabricated for microwave absorption. However, the “structure-performance” relationship between shell thickness and microwave absorption performance is rarely reported. In this paper, we first explored the “structure-performance” relationship between shell thickness and microwave absorption performance, based on the core-shell α-Fe2O3@SiO2 nanoparticles with a constant α-Fe2O3-core size and changeable SiO2-shell thickness. With increasing the SiO2-shell thickness, the microwave absorption ability first increased, then decreased. Under a proper SiO2-shell thickness of 35 nm, α-Fe2O3@SiO2 sample achieved the strongest microwave absorbing ability with a reflection loss minimum value of –4.3 dB, better than that of pure α-Fe2O3 (–3.8 dB). This enhanced microwave absorption performance was mainly derived from the dielectric loss. Although the absolute value of the reflection loss was relatively low (–4.3 dB), this study shed an important reference on designing next-generation advanced iron oxide-based materials for microwave absorption.

A State-of-the-Art Review on Core–Shell Pigments Nanostructure Preparation and Test Methods

Uses of novel technologies for improving the durability and lifespan of the construction materials have emerged as viable solutions toward the sustainable future wherein the coating industry plays a significant role in economy growth and better livelihoods. Thus, the continual innovation of various technologies to introduce diverse market products has become indispensable. Properties of materials like color stability under UV, elevated temperatures and aggressive environments, and skid and abrasion resistance are the main challenges faced by commercial coating materials, leading to more demand of natural materials as sustainable agents. Lately, nanostructured core–shell pigments with unique compositions have widely been utilized in composite materials to enhance their properties. Core–shell particles exhibit smart properties and have immense benefits when combined with building materials. Based on these facts, we comprehensively overviewed the state-of-the-art research of core–shell nanomaterials in terms of their preparation and performance evaluation methods, as well as feasible applications. The first part of this article discusses effective shell materials, including most common silica and titanium oxides. In addition, nanotechnology enabling the production and patterning of low-dimensional materials for widespread applications is emphasized. The second part deals with various potential core materials used to achieve core–shell nanostructures. The third part of this paper highlights some interesting mechanisms of core–shell structures in the modified systems that display high stability, durability, efficiency, and eco-friendliness. Finally, different applications of these core–shell nanostructures are underscored together with their test methods to evaluate their performances.

A novel core-shell nanomaterial ratiometric fluorescent probe for detecting urinary TDGA as a biomarker for VCM exposure

Thiodiglycolic acid (TDGA) is regarded as a sensitive biomarker for biological monitoring of VCM exposure. A simple, fast and reliable TDGA analysis method is of great significance to human health and the ecological environment. In this work, a novel core-shell nanomaterial based on p-type semiconductor@MOFs (Eu-CBO@Uio-66) is first prepared by in-situ growth and post-synthesis modification (PSM) as a ratiometric fluorescent probe for detecting TDGA, which shows a high sensitivity with a detection limit down to 51.1 μg L−1 (about 0.34 μM), relatively broad linear range (0–700 mg/L), fast response to TDGA within 2 min. As a result, after dispersing the resulting composite material in a solution containing TDGA, the blue emission of Eu-CBO@Uio-66 at 466 nm remains unchanged, while the red emission of Eu3+ center at 615 nm is significantly quenched, even in coexistence with other potentially analytes in the urine, so that the peak height ratio of the two emissions could be employed for determining TDGA. In addition, the significant ratiometric luminescence response caused by TDGA makes Eu-CBO@Uio-66 undergo a significant color transition from red to blue under UV-lamp, which is beneficial for visual analysis with the naked eye.