Core-shell Nanostructures Research Articles

Lipid-Polymer Hybrid Nanoparticles for Topical Drug Delivery System

Human skin not only functions as a permeation barrier (mainly due to the stratum corneum layer), but also provides a unique delivery pathway for therapeutic and other active agents. These compounds penetrate via intercellular, intracellular and transappendageal routes, resulting in topical delivery (into skin strata) and transdermal delivery (to subcutaneous tissues and into the systemic circulation). Lipid–polymer hybrid nanoparticles (LPHNPs) are next-generation core–shell nanostructures, conceptually derived from both liposome and polymeric nanoparticles (NPs), where a polymer core remains enveloped by a lipid layer. Although they have garnered significant interest, they remain not yet widely exploited or ubiquitous. Recently, a fundamental transformation has occurred in the preparation of LPHNPs, characterized by a transition from a two-step to a one-step strategy, involving synchronous self-assembly of polymers and lipids. Owing to its two-in-one structure, this approach is of particular interest as a combinatorial drug delivery platform in oncology. In particular, the outer surface can be decorated in multifarious ways for active targeting of anticancer therapy, delivery of DNA or RNA materials, and use as a diagnostic imaging agent.
 Keywords: Lipid–polymer hybrid nanoparticle, Topical delivery, Drug delivery, Gene delivery.

Tailoring porous three-dimensional (Co,Mn)(Co,Mn)2O4/PPy architecture towards high-performance cathode for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have gained extensive interest due to their cost-effective and safe nature. Nonetheless, the long-term performance of AZIBs is restricted by the conductivity and structural stability of cathode materials. Herein, the porous (Co,Mn)(Co,Mn)2O4/PPy (CMO@PPy) core–shell microspheres have been favorably synthesized using a facile solvothermal method followed by a self-polymerization process. The porous structure endows CMO@PPy with more active sites which can facilitate ion and electrolyte diffusion. And PPy as coating layers not only improve the conductivity but also buffer the structural strain of cathode material, as well as inhibit the dissolution of Mn2+. Additionally, the core–shell nanostructure can effectively release the volume expansion of cathode during the cycling process. Benefitting from the unique structure, the CMO@PPy cathode delivers a high capacity of 305.2 mAh g−1 at 0.1 A g−1 and superior long-term cycling stability (90.8 mAh g−1 at 1 A g−1 after 1000 cycles with a decay of only 0.037% per cycle). Also, the enhanced electrochemical kinetic of CMO@PPy is evaluated by Galvanostatic intermittent titration technique. Additionally, the assembled flexible ZIBs demonstrate stable electrochemical properties at different bending states, indicating their potential practical applications.

Designing a novel microfluidic sensor based on Cu(OH)2/Ni(OH)2 core–shell nanostructural arrays on the surface of SPCE as a flow injection amperometric sensor for regular insulin measurement

Herein, a novel microfluidic sensor with a small size and low dialysis fluid consumption is designed for continuous insulin measurement. The sensor is based on core–shell nanostructures consisting of Ni(OH)2 layers shelled on Cu(OH)2 nanowires which grow on screen-printed carbon electrode (Ni(OH)2/Cu(OH)2@SPCE), which is created through a simple three-step in situ technique. As a result, the sensor illustrated good electron transfer, suitable active surface area, and acceptable electrocatalytic performances. The proposed microfluidic system, including a fluid channel with a depth of about 60 μm, a modified SPCE underneath, and the experiments were carried out pumping the dialysis fluid at the flow rate of 0.3 ml min−1. It resulted in satisfactory reproducibility and acceptable repeatability with a good concentration range of 10–110 pM, considered as an appropriate candidate for practical application due to its little fluid consumption and small channel size.

Enhancing energy storage property of polymer nanocomposites by rationally regulating shell thickness of core–shell structured nanoparticles

AbstractDesign of core–shell structure for ceramic filler is an effective way to improve the electric insulation property of polymer matrix. However, it still faces the disadvantage of a low dielectric constant, inhibiting the increase in energy storage density. Herein, we propose an effective strategy for regulating shell thickness to induce dielectric polarization, which simultaneously improves dielectric constant and breakdown strength of polyvinylidene difluoride (PVDF)‐based nanocomposite incorporated by core–shell structured BaTiO3@SiO2 (BT@SO) nanoparticles. The results show that BT@SO fillers with a moderate SiO2 shell thickness of 15 nm and a low content of 1.0 vol% enhances dielectric constant and breakdown strength of PVDF‐based nanocomposite to 14.7 and 500.5 MV/m, respectively. Compared with pure PVDF, the dielectric constant and breakdown strength of PVDF/BT@SO are increased by 82.2% and 61.3%, respectively. Comprehensively, its discharge energy density is enhanced by 352%, up to 12.2 J/cm3, which is attributed to the high induced polarization of charge confinement and the multi‐function combined effects of SiO2 shell as a deep trap, barrier and adsorption layer. This study provides more insight into the interface control mechanism of core–shell nanostructure, and offers a theoretical basis for designing polymer nanocomposites with high energy storage density.

Fast and convenient delivery of fluidextracts liquorice through electrospun core-shell nanohybrids.

Introduction: As an interdisciplinary field, drug delivery relies on the developments of modern science and technology. Correspondingly, how to upgrade the traditional dosage forms for a more efficacious, safer, and convenient drug delivery poses a continuous challenge to researchers. Methods, results and discussion: In this study, a proof-of-concept demonstration was conducted to convert a popular traditional liquid dosage form (a commercial oral compound solution prepared from an intermediate licorice fluidextract) into a solid dosage form. The oral commercial solution was successfully encapsulated into the core-shell nanohybrids, and the ethanol in the oral solution was removed. The SEM and TEM evaluations showed that the prepared nanofibers had linear morphologies without any discerned spindles or beads and an obvious core-shell nanostructure. The FTIR and XRD results verified that the active ingredients in the commercial solution were compatible with the polymeric matrices and were presented in the core section in an amorphous state. Three different types of methods were developed, and the fast dissolution of the electrospun core-shell nanofibers was verified. Conclusion: Coaxial electrospinning can act as a nano pharmaceutical technique to upgrade the traditional oral solution into fast-dissolving solid drug delivery films to retain the advantages of the liquid dosage forms and the solid dosage forms.

Facile three-step strategy to design CdS@Bi2Se3 core-shell nanostructure: An efficient electrode for supercapacitor application

In this study, we utilized a successive ionic layer adsorption and reaction (SILAR) route to attach bismuth selenide (Bi2Se3) nanoparticles on one dimensional (1D) cadmium sulfide nanowires (CdS NWs) at ambient temperature (27 °C) to design CdS@Bi2Se3 core-shell nanostructure towards active electrode for supercapacitor application. To verify and explore the retrieved surface configuration, structural, elemental, compositional, and surface morphological investigations were performed. The designed CdS@Bi2Se3 core-shell nanostructure not only offers the tremendous number of active areas, but also a continuous and quick one directional electron transport channels, demonstrating noticeable electrochemical performance with specific capacitance of 198 F g−1 (aerial capacitance 59.5 mF/cm2) with 80% cyclic retention @ 2000 cycles. Superior electrochemical activity was enhanced through the mutualistic involvement of Na+ ion insertion/extraction via non-stoichiometric bismuth selenide, which was well supported through electrochemical impedance (EIS) studies.

Unraveling the Growth Process of Core–Shell Structured Upconversion Nanoparticles: Implications for Color Tuning of Upconversion Luminescence

The core–shell strategy has been routinely employed to improve emissive properties of upconversion nanoparticles (UCNPs). However, the underlying process of forming the core–shell structure still remains largely unexplored. In this work, we have performed a time-course study on the growth process of NaErF4@NaYF4 core–shell UCNPs to track time-dependent variations in size, phase, elemental distribution, and luminescence properties throughout the whole synthesis process. Our results show that the formation of core–shell UCNPs includes three major stages: formation of α-phase shell precursors, transition of the α-phase to β-phase, and seed-mediated growth. Among these stages, the first two mainly occur in the early stage of the growth process, while the last one dominates the subsequent process. During the seed-mediated growth process, the elemental distribution of the core–shell nanostructure is observed to change after a short time of reaching the reaction temperature and it continues throughout the rest of the growth process. Most importantly, the emissive properties also showed time-dependent variations, which were attributed to the activation of different optical pathways due to different shell thicknesses over time. This study is believed to provide fundamental insights into the growth mechanism of core–shell UCNPs, which can also be potentially applied for tuning the luminescence of other core–shell luminescent nanostructures.

Core-shell Fe/Fe3C heterostructure@carbon layers anchored on N-doped porous carbon for boosting oxygen reduction reaction

It is still challenging but crucial to plumb non-noble metal-based oxygen reduction reaction (ORR) catalysts with comparable or better performance than benchmark Pt/C catalysts. Herein, we proffer an unconventional core-shell-structured iron-based heterostructure electrocatalyst constructed by a Fe/Fe3C heterostructure nanoparticle core wrapped by a graphitic shell embedded on a conductive N-doped mesoporous graphite skeleton (Fe/Fe3C@NC) via facile pyrolysis of MIL-53(Fe) (MIL = Matérial Institute Lavoisier) and melamine. The Fe/Fe3C@NC catalyst delivers more positive half-wave potential (E1/2) of 0.86 V and a low Tafel slope of 56 mV dec−1 for ORR, outpacing the benchmark Pt/C catalyst, and it also shows remarkable long-term durability and excellent methanol tolerance. The marvelous ORR behaviors can be attributed to its distinctive morphologic structure: the heterostructure can enhance intrinsic ORR activity; the core-shell nanostructure can enhance ORR activities through unique electron transfer between iron species and their conductive carbon shells, which can also act as protective barriers to ensure long-term stability; the high-content pyridinic-N doping can be used as additional active centers; and the abundant mesopores facilitate the diffusion of electrolyte, which can further upgrade ORR activities. This study proffers a strategy to design and fabricate non-noble catalysts with well-designed nanoarchitecture and high catalytic activity.

Influences of Metal Core and Carbon Shell on the Microwave Absorption Performance of Cu-C Core-Shell Nanoparticles.

Metal-C core-shell nanoparticles have been recently demonstrated to be promising candidates for microwave absorption applications. However, the underlying absorption mechanism, such as the contributions of the metal cores and C shells on their absorption performance, remains far from clear due to the complicated interfaces and synergetic effects between metal cores and C shells, as well as the significant challenges in the preparation of samples with well-defined comparability. In this study, Cu-C core-shell nanoparticles and their derivatives, i.e., bare Cu and hollow C nanoparticles, were synthesized for a comparative study on their microwave absorption properties. Electric energy loss models of the three samples were established, and based on these models, the comparative study suggested that the polarization loss could be significantly improved by C shells, and Cu cores had negligible influences on the conduction loss of Cu-C core-shell nanoparticles. The interface between C shells and Cu cores tuned the conduction loss and polarization loss to establish improved impedance matching and achieve optimal microwave absorption performances. A wide effective bandwidth of 5.4 GHz and a low reflection loss of -42.6 dB were achieved for Cu-C core-shell nanoparticles. This work provides new insights into how metal nanocores and C nanoshells affect the microwave absorption of core-shell nanostructures from experimental and theoretical points of view, which has reference values for the construction of highly efficient metal-C-based absorbers.

Triple-Mode upconversion emission for dynamic multicolor luminescent anti-Counterfeiting

Lanthanide (Ln3+) luminescent materials play a crucial role in information security and data storage owing to their excellent and unique optical properties. The advances in dynamic colorful luminescent anti-counterfeiting nanomaterials enable the generation of a high-level information encryption. In this work, a superior thermal, optical wavelength and excitation power triple-mode stimuli-responsive emission color modulation is demonstrated in a lanthanide-doped nanostructured luminescent material. The plentiful emission colors are manipulated by modulating the composition of a fluoride core–shell nanostructure with different Ln3+ at different doping concentrations. The nanomaterials display remarkable excitation wavelength/power-dependent color change, along with temperature-dependent color variation in the range from 298 K to 437 K, with a good relative sensitivity Sr of 1.1387% K−1 at 398 K. The universal optical modulation, combined with the excellent optical and structural stability of the luminescent nanoparticles, renders many advantages for the anti-counterfeiting application. This work explores a universal strategy for the manipulation of triple-mode stimuli-responsive dynamic luminescence and demonstrates its good potential for anti-counterfeiting application.

Synthesis, structural, and optical properties of (Ag/ZnS) core–shell nanostructures and their applications to polycrystalline silicon solar cells

The present work focuses on the two-step chemical synthesis of Ag/ZnS nanoparticles as core–shell nanoparticles. Various techniques were used to characterize nanoparticles, including UV–Vis spectroscopy, Dynamic Light Scattering, Transmission Electron Microscopy, Fourier Transform Infrared Spectroscopy, and a Solar Simulator. UV–Vis spectral analysis of Ag/ZnS core–shell nanoparticles at 450, 469, and 498 nm reveals broad plasmon resonance bands. The solution of silver nanoparticles was redshifted by increasing its concentration. Core and shell images obtained from each nanoparticle show different contrasts, indicating that the core and shell materials differ. Infrared spectroscopy confirmed the presence of ZnS NPs around AgNPs. Incorporating Ag/ZnS into polycrystalline silicon solar cells has improved efficiency from 13.02 to 14.29%.

Development of Highly Stable and Sensitive SAW UV Sensor Based on Ta2O5 Coated 1D ZnO/SnO2 Core–Shell Nanostructures

AbstractDespite extensive research on ultraviolet (UV) sensors based on core–shell heterostructures, most of them exhibit low sensitivities, slow response/recovery times, and unsatisfactory long‐term stabilities, thereby limiting their use in real‐time applications. To solve these problems, a highly sensitive and stable surface acoustic wave (SAW) UV sensor based on novel tantalum pentoxide (Ta2O5) coated 1D zinc oxide (ZnO)/tin dioxide (SnO2) core–shell nanostructures is introduced. The fabricated SAW‐based UV sensor system, including sensor interface electronics, exhibits a high UV response, fast response/recovery time, and long‐term stability. Prior to device fabrication, coupling of mode (COM) modeling is performed to calculate the optimal parameters for the SAW device. Photoluminescence and X‐ray photoelectron spectroscopy measurements reveal that the Ta2O5 layer coating effectively suppresses the recombination of photogenerated carriers, leading to an increase in the carrier density and improvement in the UV sensing properties. The evaluated sensitivity and linearity of the proposed sensor are 120.36 ppm (mW cm−2)−1 and 0.988, respectively, in the range of 1–60 µW cm−2. The sensing mechanism of the proposed UV sensor is discussed in detail. Using COMSOL simulations and photo‐corrosion experiments, it is found that the Ta2O5 coated ZnO/SnO2 core–shell heterostructure minimizes the effects of humidity and improves stability.

The effects of temperature, contact time, and molar ratio of HCl:KMnO4 on the morphology of FeNi3/MnO2 core-shell nanostructure and its application in microwave absorption

In this study, we aimed to fabricate FeNi3@MnO2 core-shell structures using the hydrothermal method for the first time and investigated the effect of temperature, time, and molar ratio of HCl: KMnO4 on the structure, morphology, and absorption of electromagnetic waves. X-ray diffraction analysis showed that the FeNi3@MnO2 structure was formed, which was increased by increasing the reaction temperature and time. However, the intensity of FeNi3 peaks was decreased though the intensity and number of MnO2 peaks were increased. The morphology was studied using field emission scanning electron microscopy and transmission electron microscopy, which showed that a core-shell structure was formed at 100 °C for 3 h with a molar ratio of 1:1. The hysteresis loops of the samples showed that the value of saturation magnetization is decreased by increasing the temperature, time, and molar ratio. Microwave absorption was investigated in the 2–18 GHz frequency range, which indicated a better reflection loss of −34 dB in GHz with a thickness of 1.5 mm.

Quenching effect in luminescent and magnetic properties of Fe3O4/α-Fe2O3/Y2O3:Eu3+ nanocomposites

In this paper, Fe3O4/α-Fe2O3/Y2O3:Eu3+ multifunctional nanocomposites were synthesized using a hydrothermal method. Fe3O4/α-Fe2O3/Y2O3:Eu3+ nanocomposites are core-shell nanostructures consisting of a superparamagnetic nanomagnetite core, which is converted to hematite during the synthesis. As a theranostic material, hematite could be used in drug-release processes, while nanomagnetite generates heat in a hyperthermia cancer treatment. An outer shell of Y2O3:Eu3+ nanophosphor is added to give nanocomposites photoluminescent properties and to render them visible in bioimaging. Structural, optical, and magnetic features of nanocompositesare studied using X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), Raman, photoluminescence (PL), vibrating-sample magnetometer (VSM), and high-resolution transmission electron microscope (HRTEM) techniques. Photoluminescence properties of nanocomposites show a quenching effect related to the proportion of magnetite and Y2O3:Eu3+. A luminescence quenching mechanism is proposed based on the optical effects of a core-shell structure. Magnetic saturation grows proportionally with the amount of magnetite present, which indicates that Fe3O4 magnetic structure is not altered, even by the hematite that forms around it. The synthesized nanocomposites possess a core-shell morphology modified by the different proportions of their components. The optical, structural, and magnetic nanocomposite properties found will be of interest in theranostic materials research in the biomedical field.

Template-Directed Polymerization of Binary Acrylate Monomers on Surface-Activated Lignin Nanoparticles in Toughening of Bio-Latex Films.

Fabricating bio-latex colloids with core-shell nanostructure is an effective method for obtaining films with enhanced mechanical characteristics. Nano-sized lignin is rising as a class of sustainable nanomaterials that can be incorporated into latex colloids. Fundamental knowledge of the correlation between surface chemistry of lignin nanoparticles (LNPs) and integration efficiency in latex colloids and from it thermally processed latex films are scarce. Here, an approach to integrate self-assembled nanospheres of allylated lignin as the surface-activated cores in a seeded free-radical emulsion copolymerization of butyl acrylate and methyl methacrylate is proposed. The interfacial-modulating function on allylated LNPs regulates the emulsion polymerization and it successfully produces a multi-energy dissipative latex film structure containing a lignin-dominated core (16% dry weight basis). At an optimized allyl-terminated surface functionality of 1.04mmol g-1 , the LNPs-integrated latex film exhibits extremely high toughness value above 57.7MJ m-3 . With multiple morphological and microstructural characterizations, the well-ordered packing of latex colloids under the nanoconfinement of LNPs in the latex films is revealed. It is concluded that the surface chemistry metrics of colloidal cores in terms of the abundance of polymerization-modulating anchors and their accessibility have a delicate control over the structural evolution of core-shell latex colloids.

In situ fabrication of recyclable CuO@MoS2 nanosheet arrays-coated copper mesh for enhanced visible light photocatalytic degradation of tetracycline and microbial inactivation

The recycling technology of the photocatalyst powdery has hardly matured in the photocatalytic water treatment so far. In this study, a novel CuO@MoS2 core–shell nanostructure grown on the copper mesh was quickly fabricated through in situ engraving and hydrothermal deposition methods. The metallic Cu mesh is employed as the Cu source, substrate, and conductor. Also, the tight contact of CuO nanosheet arrays and MoS2 nanosheet results in a shorter migration distance of photogenerated carriers to the surface of the Cu@CuO@MoS2 mesh (CCM). Benefiting from this rational design of CCM and effective charge separation by Z-scheme charge transfer, the readily recyclable CCM exhibits superior photodegradation efficiency with 79% removal of tetracycline (10 mg/L) in 120 min, which was better than that of Cu@CuO (42%) and Cu@MoS2 (44.3%) under identical conditions. Furthermore, CCM mesh can be used for microbial inactivation, and the antibacterial efficiency reaches about 100% for Escherichia coli within 60 min visible light irradiation. Additionally, the CCM mesh photocatalyst indicates high reusability and stability without significant reduction in efficiency with nearly 69% degradation and 100% microbial inactivation after 5 cycles, respectively. This study provides a simple strategy to prepare a recyclable free-standing mesh photocatalyst for the treatment of pollutants and bacteria in wastewater.

Functional nanoparticles from chemically coupled precipitation processes

Coupled chemical reactions are known to produce ordered patterns under certain conditions far from thermodynamic equilibrium. Such phenomena can be exploited to obtain complex mineral structures, as reported for self-assembled composites of crystalline carbonates and amorphous silica. In the present work, we show that the dynamic pH-based coupling underlying the formation of these inorganic composites can be extended to produce core-shell nanostructures of functional materials. Specifically, the concept was applied to synthesize fluorescent silica-coated quantum dots in a simple one-pot procedure at ambient conditions based on the coupled co-precipitation of metal chalcogenides and silicate. This straightforward approach can likely be generalized to produce a broad variety of functional nanoparticles with possible applications in the areas of optics, energy storage, catalysis, and beyond.

High–performance water electrolyzer with minimum platinum group metal usage: Iron nitride–iridium oxide core–shell nanostructures for stable and efficient oxygen evolution reaction

To reduce the usage of rare-earth metals in a proton-exchange-membrane water electrolyzer (PEMWE), a highly active water-oxidizing anode based on a core–shell catalyst structure was developed. Earth-abundant metal-based iron-nitride nanostructure was adopted to support thin, electrodeposited iridium-oxide films. PEMWEs with core–shell nanostructure has substantially low ohmic and mass-transfer resistances, suggesting that the introduction of Fe2N nanostructure on Ti PTL enhances the transfer of protons, water, and oxygen on the catalyst layer. Furthermore, a high Ir mass activity of 103 A/mgIr was achieved with reduced Ir loading of 0.036 mg/cm2 on the Ti PTL. The well-known weakness of transition-metal nitrides (TMNs) for use in PEMWEs, that is, their chemical instability in corrosive acidic environments, was overcome by carefully passivating the surfaces of the TMNs with chemically stable Ir catalyst layers. As a result, the prepared core–shell-structured catalysts were stable under the PEMWE operating condition.

Biocompatible gliadin-sericin complex colloidal particles used for topical delivery of the antioxidant phloretin

Oxidative stress caused by environmental exposures results in numerous skin diseases. Phloretin (PHL) is often used to relieve various skin symptoms, however, precipitation or crystallization of PHL in aqueous systems limits its ability to diffuse through the stratum corneum, making it difficult to exert effect at the target. To address this challenge, we herein report a method for the generation of core–shell nanostructure (G-LSS) via the growth of sericin crust around gliadin nanoparticle as a topical nanocarrier of PHL to improve its cutaneous bioavailability. Physicochemical performance, morphology, stability, and antioxidant activity of the nanoparticles were characterized. G-LSS-PHL exhibited uniformed spherical nanostructures with the robust encapsulation on PHL (∼90 %). This strategy protected PHL from UV-induced degradation, facilitating to inhibit erythrocyte hemolysis and quench free radicals in a dose-dependent manner. Transdermal delivery experiments and porcine skin fluorescence imaging indicated that G-LSS facilitated the penetration of PHL across the epidermis layer of skin to reach deep-seated sites, and promoted cumulative turnover of PHL with a 2.0-fold increase. Cell cytotoxicity and uptake assay confirmed that as-prepared nanostructure was nontoxic to HSFs, and promoted cellular absorption of PHL. Therefore, this work opened up new promising avenues for developing robust antioxidant nanostructure for topical applications.

Engineering of plasmonic metal-semiconductor yolk-shell nanostructures for multi-intensified photodynamic- and immuno- therapy against drug resistant bacteria

Photodynamic therapy (PDT) as well as immunotherapy are effective therapies to combat the systemic infection. Nevertheless, the development of the treatments are restrained by the lack of efficient photosensitizers (PS) and the genetic diversity of the bacteria. Here, we report Ag doped Au-CdS1−ySey yolk-shell nanostructures (AYSs) which exhibit excellent near-infrared (NIR) light induced PDT and immunotherapy performance. The tailored plasmonic Au nanorods (NRs) are able to gather the NIR light, offering the basis for PDT. Moreover, high yield of reactive oxygen species (ROS) is achieved through the following creativity: i) enhanced light trapping ability by the microcavity, ii) smooth injection process of hot electrons (HEs) by the suitable band gap alignment, iii) inhibiting the combination of electric charges by the doped Ag with appropriate concentration. Therefore, the AYSs exhibit more 30 times of ROS production as well as lower 64 times of MIC than the conventional core-shell nanostructures. Notably, repeated enhanced antibacterial PDT are carried out to obtain versatile antigens from various dead bacteria to awaken the immune cells adequately and boost immune response with the help of Selenium (Se) which is distributed in the shell. As a result, the systemic drug resistant bacterial infection is cured successfully.