In this study, a hybrid dual drug-loaded hydroxyapatite-oxidized dextran methacrylate core–shell nanocarrier was formulated and explored for combinatorial delivery of doxorubicin (DOX) and methotrexate (MTX) to bone cancer. The synthesized nanocarrier was well characterized by different techniques. In vitro drug release studies in both acidic (pH 5) and alkaline (pH 7.4) conditions showed sequential release of MTX followed by DOX in a sustained manner for 10 days. Biocompatibility and cytotoxicity studies performed using drug-loaded nanoparticles (NPs) on fibroblast L929 cells and osteosarcoma MG63 cells (OMG63) showed that the NPs were highly biocompatible and showed concentration-dependent toxicity. Gene expression studies in OMG-63 cells exhibited the upregulation of caspase-3 and BAX which confirmed the apoptosis induced by dual drug-loaded NPs. The nanocarrier is expected to be a potential bone void filling material, as well as a platform for sequential delivery of DOX and MTX for the treatment of bone cancer.

To advance the utilization of solar thermal energy, a novel solar-driven microcapsule was designed by the combination of high-performance CuS nanoconverter and the microencapsulated n-Eicosane with a brookite TiO2 shell via in situ sol–gel method. The resultant n-Eicosane@TiO2/CuS microcapsules possessed excellent thermal properties with high latent heat density (171.7 J/g), high encapsulation efficiency (71.7%), and increased thermal conductivity (0.730 W/(m K)). SEM analysis clearly verified that CuS nanoparticles exhibited a uniform distribution on the surfaces. Most of all, the addition of CuS not only enlarged the absorption spectra from the UV to the visible and NIR region but also achieved high solar-to-thermal conversion efficiency (94.41%). Due to the high heat storage capability and solar irradiation utilization efficiency, this solar-driven microcapsule possesses great potential for the solar energy utilization.

In this paper, we report a recent theoretical study of the calculation of the binding energy and photoionization cross section of a single dopant in a spherical hollow or core/shell quantum dot taking into account the interaction of the electron with longitudinal optical phonons. Using Frolich approach and Lee-low Pines transformation, we determine the impact of different parameters such as shell thickness and dopant position on the energy and optical response of a bound polaron for two types of ionic II–VI semiconductors CdTe and ZnSe with different phonon coupling constants. Regardless of the material used, the electron–phonon interaction visibly reduces binding energy. For photoionization cross section, a redshift of resonance peaks was found when the effect of phonons is taken into consideration or when the donor is moved away from the shell center. These calculations provide us insights when choosing between materials for optoelectronic applications.

Effective cancer therapy is usually limited by the off target distribution of chemotherapeutic drugs and multidrug resistance (MDR) of cancer cells. As a result, the development of a drug delivery system (DDS) capable of targeting cancer cells while at the same time delivering two or more chemotherapeutic drugs is believed to be a good solution to this dilemma. Herein, a hyaluronan-coated meta-organic framework nanoparticles (HM) were fabricated as a DDS in our study to deliver cisplatin (PDD) and oleanolic acid (Ola). Positive results were obtained in our study which reveal that the DDS (HM/PDD/Ola) is favorable in colorectal cancer (HCT116) therapy by enhancing targeted apoptosis and reversing MDR. Compared with applying free drugs or mono DDS, the dual loaded HM/PDD/Ola showed synergistic effects and better performance, which might be a future alternative for the chemotherapy of colorectal cancer.

The polymerization of 3,4-ethylenedioxythiophene (EDOT) onto nanosilica (SiO2) was synthesized in this study by using supercritical carbon dioxide (SCCO2). With the addition of dopants of p-toluenesulfonic acid (p-TSA) or decylbenzene sulfonic acid (DBSA), the PEDOT/SiO2 composite became conductive. The product was characterized by FTIR spectroscopy and the core-shell structure was confirmed through the TEM images. The electrical properties were analyzed by UV-vis absorbance and four-point probe measurement. DBSA is shown as the better dopants with the molar ratio (DBSA/EDOT) of 0.2 at the reaction time of 48 hours. The maximum coating percentage is 63 wt% under the optimal operation conditions at 40oC and 280 bar. The conductivity is tuned up to 6.6×10-2 S/cm after the coating process.

Chalcopyrite quantum dots (QDs) have emerged as a safe alternative to cadmium-based QDs for bio-applications. However, the research on AgInS2 chalcopyrite QDs has not been widely explored in terms of their toxicity. Herein, we report a synthesis of biocompatible AgInS2/ZnS QDs via a greener approach. The emission intensity of the as-synthesized AgInS2 core QDs was enhanced 2-fold after the ZnS shell growth. X-ray diffraction revealed the tetragonal crystal structure of QDs, and high-resolution transmission electron microscope images show that the QDs are spherical in shape and crystalline in nature. Cell viability assays conducted on different cell lines, such as HeLa, A549, and BHK-21 cells, indicated that AgInS2/ZnS QDs are least toxic at a QD concentration range of 100 µg/mL. The fluorescent microscope analysis of A549 cells incubated with AgInS2/ZnS QDs shows that the QDs were accumulated in the cell membranes. The as-synthesized AgInS2/ZnS QDs are less toxic and eco-friendly, and can be used for biolabeling.

Multifunctional nanoparticles are an emerging area of research, impacting numerous fields ranging from biomedical applications to energy. While initial core–shell structures consisted of similar materials, such as Au–Ag or CdTe–CdSe nanoparticles, recent work has expanded this line of investigation to include particles of dissimilar materials. However, there are several challenges when synthesizing dissimilar material systems. In this work, a method for doping the shell of an Au–ZnO nanosphere is demonstrated. Several metal dopants are investigated, including Cu, Ce, Er, Nd, Tm, and Yb. The ZnO shell is nucleated on the gold nanosphere core via an ascorbic acid–assisted growth, and the dopant is intercalated uniformly into the shell during the self-assembly phase of the shell formation. The doping and polycrystalline shell are confirmed using a series of qualitative and quantitative methods. This multi-material nanoparticle synthesis strategy opens the door for future applications in sensing, photocatalysis, and bioimaging.

Electrospun coaxial fibers are used to create core/sheath fiber structures to act as growth-promoting scaffolds for in vitro dorsal root ganglia (DRG) cell cultures. The core was a conducting polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), and the sheath was poly-L-lactic acid (PLLA), which created coaxial fibers with a conductive core and an insulating sheath. SEM analysis confirmed the conductivity of the core and insulation of the sheath. Several coaxial spinneret designs were tested with the best results obtained by using various annular spinning needle combinations. Using a 22G/16G and 22G/17G combination, fibers with diameters of 6.1 ± 2.4 µm and 3.3 ± 0.9 µm were spun, respectively. The fibers showed a Young’s modulus and hardness of 0.16 ± 0.13 and 0.02 ± 0.01 GPa for the larger diameters, and 0.7 ± 0.4 and 0.03 ± 0.03 GPa for the smaller diameter fibers. In vitro test cultures showed the fibers successfully directed chick DRG axonal outgrowth with low biotoxicity.

Noble metal (Ag, Au) nanoparticles (NPs) deposited on the surface of three-dimensional (3D) materials are promising 3D surface-enhanced Raman spectroscopy (SERS) substrates. In this work, the authors reported the preparation of 3D wax/silica/Ag(Au) colloidosomes by sulfonic acid group–terminated silica spheres (SiO2–SO3H) combined with a Pickering emulsion technique, as well as seed-mediated growth method of noble metal NPs. The presence of –SO3H group on the silica spheres not only improves significantly the quality of wax/silica colloidosomes (forming perfect silica shell around wax droplet) but also can adsorb metal precursor ions via electrostatic attraction for further growth of metal NPs. The size and coverage of Ag(Au) NPs on wax/silica droplets can be facilely tuned, and relevant wax/silica/Ag(Au) colloidosomes and silica/Ag(Au) Janus particles are obtained via this strategy. The obtained wax/silica/Ag colloidosomes as 3D SERS substrates exhibited excellent SERS enhancement ability and detection limit of 4-aminothiophenol reached 10−9 M.

We report the first synthesis of highly homogenous Ce-doped YAG/ZnO core/shell nanoparticles (YAG:Ce/ZnO CSN) based on the hydrolysis/condensation of Zn(OAc)2 on the surface of YAG:Ce nanoparticles (NPs). Results show that YAG:Ce NPs of about 100 nm diameter are homogenously surrounded by a multilayer of highly crystallized ZnO nanocrystals (ZnO NCs) of 10–15 nm diameter with a core/shell structure. The as-prepared nanostructures have been used in the photocatalytic degradation of sulfathiazole (STZ), which is a molecule widely used as antibiotic, under UV-vis and visible light. The effect of YAG:Ce/ZnO weight ratio and YAG:Ce particle size on the photocatalytic efficiency of YAG:Ce/ZnO core/shell structures has been studied. The YAG:Ce/ZnO weight ratio of 1/1 was found to yield the optimal photocatalytic activity. Results also showed that YAG:Ce/ZnO CSN with 100 nm core size exhibited much higher photocatalytic activity compared to YAG:Ce/ZnO CSN with micro-sized YAG;Ce core. The recyclability of YAG:Ce/ZnO CSN photocatalyst was also demonstrated over at least 10 photocatalytic degradation cycles.

The mechanical properties of core–shell bimetallic composite nanowires, forming the bases of nanoporous metallic foams, have been investigated and compared with pure metal nanowires using molecular dynamics simulations. In the current study, pure copper and gold nanowires under uniaxial loading were tested at room temperature and compared to composite nanowires of the same materials (core) with a nickel coating (shell). The core radius ranged from 1 to 15 nm, and the shell thickness ranged from 0.1 to 5 nm. The tension strain was performed along the [001] direction under room temperature. Both coherent and semi-coherent composite nanowires were studied, and the effect of coating layer thickness was investigated. The strengthening mechanisms of the core–shell structures due to the presence of the two different types of interfaces were investigated for various nickel thicknesses. The atomistic simulation results revealed that the addition of the nickel shell strengthens the structure when the layer thickness exceeds a critical value.

Several technologically important alloys like Al-Li-Zr, Al-Li-Sc, Al-Sc-Zr, Al-Li-Sc-Zr, modified Inconel etc., exhibit compact precipitates in their microstructure. We present a phase-field model in two dimensions to study the morphological evolution of composite precipitates in ternary alloys. The model employs a modified regular solution description of the bulk free energy of the disordered matrix phase and ordered precipitates. Elastic strain energy of the three-phase system is described using Khachaturyan’s microelasticity theory. The temporal evolution of the spatially dependent field variables is determined by numerically solving coupled Cahn-Hilliard and Allen-Cahn equations for composition and order parameter fields, respectively. We systematically vary the misfit strains, alloy chemistry and mobilities of the diffusing species to study their effect on the development of compact precipitates. Compact core-shell morphology destabilizes when the precipitate phases have misfit strains of opposite signs with the matrix phase although the relative interfacial energies between the phases satisfy Cahn’s spontaneous wetting condition. Thus, the stability of “monodisperse” core-shell microstructures is determined by the interplay between the relative interfacial energies and elastic interactions between the phases. Further, our simulations show that low solute mobility within the core leads to sluggish coarsening of the compact particles.

Lithium sulfide (Li2S) is one of the most attractive cathode materials for high energy density lithium batteries as it has a high theoretical capacity of 1166 mA h g-1. However, Li2S suffers from poor rate performance and short cycle life due to its insulating nature and polysulfide shuttle during cycling. In this work, we report a facile and viable approach to address these issues. We propose a method to synthesize a Li2S based nanocomposite cathode material by dissolving Li2S as the active material, polyvinylpyrrolidone (PVP) as the carbon precursor, and graphene oxide (GO) as a matrix to enhance the conductivity, followed by a co-precipitation and high-temperature carbonization process. The Li2S/rGO cathode yields an exceptionally high initial capacity of 817 mAh g-1 based on Li2S mass at C/20 rate and also shows a good cycling performance. The carbon-coated Li2S/rGO cathode demonstrates the capability of robust core-shell nanostructures for different rates and improved capacity retention, revealing carbon coated Li2S/rGO composites as an outstanding system for high-performance lithium-sulfur batteries.

We report on the results of coherent X-ray diffraction imaging (CXDI) and ptychography measurements of two individual core-shell-shell GaAs/(In,Ga)As/GaAs nanowires (NWs) grown by molecular beam epitaxy (MBE) on patterned Si(111) substrate. CXDI at the axial GaAs 111 Bragg reflection was applied at different positions along the NW axis in order to characterize the NWs in terms of structural homogeneity along the radial directions. At each positon 3D reciprocal space maps have been recoded and inverted using phase retrieval algorithms. The CXDI were complemented by 2D ptychography measurements at GaAs 111 Bragg reflection probing the same NWs with respect to their structural homogeneity. Both methods provide structural homogeneity for NW1 and NW2 except at the bottom part of the NWs. In case of NW2 CXDI and ptychography show changes in the structure of the top part of the NW indicated by 60° rotation of the indicated three-fold rotational symmetry in the observed diffraction patterns and changes in the strain field reconstructed from ptychography.

Stimuli-responsive materials with controlled reversible wettability find diverse application as self-cleaning surfaces, tunable optical lenses and microfluidic devices. We report on an electrochemical approach for dynamic control over the wetting properties of additive-free Cu/CuxO core-shell dendritic structures. By varying the oxidation state of the oxide shell phase, the entire wettability range spanning superhydrophobicity (contact angle > 150°) to superhydrophilicity (contact angle < 10°) can be precisely adjusted in-situ. During the wetting transitions, the surface transforms from a low adhesive rolling state (lotus effect) to high adhesive pinning state (petal effect), and eventually to superhydrophilic state with a water-absorbing ability (fish scale wetting). The wetting alteration is reversible via air-drying at room temperature or mild heat drying at 100°C. The reversibly redox-driven wettability switching is demonstrated for controllable oil-water separation with efficiency higher than 98 percent.

Tunable plasmonic resonances across the visible and near infrared spectra have provided novel ways to develop next-generation nanophotonic devices. Here, by utilizing optothermally controllable phase-changing material (PCM), we studied highly tunable charge transfer plasmon (CTP) resonance modes. To this end, we have designed a two-member dimer assembly including gold cores and Ge2Sb2Te5 (GST) shells in distant, touching, and overlapping conditions. We successfully demonstrated that toggling between amorphous (dielectric) and crystalline (conductive) phases of GST allows for achieving tunable dipolar and CTP resonances along the near-infrared spectrum. The proposed dimer structures can help forming optothermally controlled devices without further morphological variations in the geometry of the design, and having strong potential for advanced plasmon modulation and fast data routing.

This study reports a high-performance tin (Sn)-coated vertically aligned carbon nanofiber array anode for lithium-ion batteries. The array electrodes have been prepared by coaxial sputter-coating of tin (Sn) shells on vertically aligned carbon nanofiber (VACNF) cores. The robust brush-like highly conductive VACNFs effectively connect high-capacity Sn shells for lithium-ion storage. A high specific capacity of 815 mAh g-1 of Sn was obtained at C/20 rate, reaching toward the maximum value of Sn. However, the electrode shows poor cycling performance with conventional LiPF6 based organic electrolyte. The addition of fluoroethylene carbonate (FEC) improve the performance significantly and the Sn-coated VACNFs anode shows stable cycling performance. The Sn-coated VACNF array anodes exhibit outstanding capacity retention in the half-cell tests with electrolyte containing 10 wt.% FEC and could deliver a reversible capacity of 480 mAh g-1 after 50 cycles at C/3 rate.

Ce3+ ions in ceria nanoparticles (NPs) play a role as reactive sites in the adsorption of silicate anions. However, the limited concentration of Ce3+ ions in ceria NPs remains a major challenge in this regard. Herein, we report a simple strategy to synthesize Ce3+-enriched core–shell ceria NPs for enhanced adsorption of silicate anions. To increase the overall Ce3+ concentration, a shell layer is composed of Ce3+-rich ultrasmall ceria NPs approximately 5 nm in size. The Ce3+ concentration of such core–shell ceria NPs is increased by 12.7–17.1% relative to that of the pristine ceria NPs, resulting in increased adsorption of silicate anions. The Freundlich model fits the observed adsorption isotherm well and the constants of adsorption capacity (KF) and adsorption intensity (1/n) indicate higher adsorption affinity of the core–shell ceria NPs for silicate anions. We attribute these improvements to the increased Ce3+ concentration contributed by the ultrasmall ceria coating. This strategy can be used for enhancing the reactivity of ceria materials.

Magnetic core–shell nanoparticles (CSNs) have potential applications in spintronic devices, drug delivery systems, and magnetic random access memory. By use of our hydrothermal nano-phase epitaxy method, we have accomplished synthesis of novel, well-ordered α-Cr2O3@α-Mn0.35Cr1.65O2.94 inverted CSNs. XRD and TEM analyses show a core–shell structure with corundum phase throughout the core and shell with a minimal amount of interface defects. TEM-EDX and XPS data show Mn having the +2 oxidation state in the shell of the CSNs. Magnetization measurements at 5 K show a weak coercivity (H C) value of 8 Oe and an exchange bias field (H E) of 293 Oe. Ab initio calculations show that Mn incorporation in α-Cr2O3 results in narrowing of the energy band gap, substantiated by UV–Vis measurements, and half metallic behavior in case of Mn(III) substitution. Our calculations substantiate that Mn substitution in α-Cr2O3 results in a combination of antiferromagnetic and weak ferrimagnetic character of our CSNs.

Emissive PbS/CdS core/shell nanosheets are synthesized using a cation-exchange method. A significant blue-shift of the photoluminescence is observed, indicating a stronger quantum confinement in the PbS core as its thickness is reduced to eight atomic layers. High resolution transmission-electron-microscopy images of the cross-sections of the core/shell nanosheets show atomically sharp interfaces between PbS and CdS. Accurate analysis of the thickness of each layer reveals the relationship between the energy-gap and the thickness in the extremely one-dimensionally confined nanostructure.