Hybrid Nanosystems Research Articles

Magnetic, fluorescent and hybrid nanoparticles: From synthesis to application in biosystems.

Multifunctional nanoparticles have emerged as an outstanding candidate for a new generation of biomedical applications, mainly due to their remarkable properties and biocompatibility. Individual reports on multi-metal, semiconducting and superparamagnetic nanoparticles (SPIONs), elucidating on each's unique intrinsic properties, have demonstrated that the biological application of such materials is highly dependent of their size, shape, surface nature and core nature. However, reviews combining nanoparticles with multiple properties, as fluorescence and paramagnetism, as well as, biocompatibility, toxicology and biodegradability are yet seldom. This review highlights the highest output advances, of the last decade, on synthetic procedures for the design of multifunctional magneto-luminescent hybrid nanosystems based on quantum dots, SPIONs and mesoporous silica nanoparticles, as well as, surface modifications and their role for biological applications.

Reduction of Tetrachloroaurate(III) Ions With Bioligands: Role of the Thiol and Amine Functional Groups on the Structure and Optical Features of Gold Nanohybrid Systems.

In this review, the presentation of the synthetic routes of plasmonic gold nanoparticles (Au NPs), fluorescent gold nanoclusters (Au NCs), as well as self-assembled Au-containing thiolated coordination polymers (Au CPs) was highlighted. We exclusively emphasize the gold products that are synthesized by the spontaneous interaction of tetrachloroaurate(III) ions (AuCl4¯) with bioligands using amine and thiolate derivatives, including mainly amino acids. The dominant role of the nature of the applied reducing molecules as well as the experimental conditions (concentration of the precursor metal ion, molar ratio of the AuCl4¯ ions and biomolecules; pH, temperature, etc.) of the syntheses on the size and structure-dependent optical properties of these gold nanohybrid materials have been summarized. While using the same reducing and stabilizing biomolecules, the main differences on the preparation conditions of Au NPs, Au NCs, and Au CPs have been interpreted and the reducing capabilities of various amino acids and thiolates have been compared. Moreover, various fabrication routes of thiol-stabilized plasmonic Au NPs, as well as fluorescent Au NCs and self-assembled Au CPs have been presented via the formation of –(Au(I)-SR)n– periodic structures as intermediates.

Simultaneous paramagnetic and persistence-luminescence in GAGG:Ce,Pr nanoparticles synthesized by sol-gel for biomedical applications

Nanohybrid systems combining both persistent luminescence and magnetic property are recent breakthroughs in novel multimodal imaging and cancer therapy; however, integrating strategies at a common platform is complex. Herein, we report the synthesis of a Gd3Al5−xGaxO12:Ce3+,Pr3+ (GAGG:Ce,Pr) nanophosphor (x = 1–5) with simultaneous paramagnetic/persistence luminescence via a simple tartaric acid assisted solgel synthesis. Structural analysis revealed the formation of a pure cubic garnet crystal of GAGG:Ce,Pr, which expanded linearly upon gallium incorporation. Moreover, the novel paramagnetic/persistence luminescent material showed the formation of nanoparticles with excellent colloidal stability. Photoluminescence emission analysis showed a broad emission band in the range of λ = 500–750 nm attributed to (5d → 4f) transitions of Ce3+ and a sharp peak centered at λ = 612 nm attributed to electronic transitions (1D2 → 3H4) within Pr3+ upon blue light excitation. In particular, GAGG:Ce-Pr sample with Al:Ga ratio 1:4 yielded persistent luminescence upon blue, UV, and white light excitation at room temperature. Additionally, GAGG:Ce-Pr (x = 4) nanophosphor was paramagnetic and also showed signs of weak ferromagnetism at ambient temperature. Cellular toxicity analysis in different cell lines revealed the relatively safe nature of nanoparticles at the tested concentrations. Overall, in our preliminary analysis, GAGG:Ce-Pr (x = 4) showed the persistent optomagnetic property and low cellular toxicity for potential utilization in multimodal theranostic applications.

Nanodot-Directed Formation of Plasmonic-Fluorescent Nanohybrids toward Dual Optical Detection of Glucose and Cholesterol via Hydrogen Peroxide Sensing.

Hybrid nanoparticles (NPs) have emerged as an important class of nanomaterials owing to their integrated enhanced properties and functionality. In this study, we have developed an effective nanodot templating strategy for the in situ formation of surfactant-free nanohybrids with unique plasmonic-fluorescent properties. A bright photoluminescent biodot synthesized from serine and histamine biomolecular precursors (Ser-Hist dot) was first engineered to have rich functional groups on the nanosurface capable of anchoring Ag+ ions via electrostatic interaction. Upon UV irradiation, free electrons could transfer from the photoexcited Ser-Hist dot to the Ag+ ions, facilitating the in situ growth of AgNPs. The resulting nanohybrid system (Bio@AgNPs) exhibits distinct characteristic surface plasmon resonance absorbance and highly quenched PL intensity due to the inner filter effect. Furthermore, the Bio@AgNP nanohybrid retains its redox capability, enabling hydrogen peroxide sensing via AgNP etching, which in turn empowers a dual colorimetric and fluorescent detection of glucose and cholesterol in complex biological samples (i.e., synthetic urine and human plasma) with high selectivity and sensitivity. This finding reveals a new effective and facile method for the preparation of highly functional hybrid nanomaterials for dual-mode detection of hydrogen peroxide-producing species and/or reactions.

Porous Organic Polymer-Driven Evolution of High-Performance Cobalt Phosphide Hybrid Nanosheets as Vanillin Hydrodeoxygenation Catalyst.

Hydrodeoxygenation (HDO) is a promising route for the upgrading of bio-oils to eco-friendly biofuel produced from lignocellulose. Herein, we report the sequential synthesis of a hybrid nanocatalyst CoxP@POP, where substoichiometric CoxP nanoparticles are distributed in a porous organic polymer (POP) via solid-state phosphidation of the Co3O4@POP nanohybrid system. We also explored the catalytic activity of the above two nanohybrids toward the HDO of vanillin, a typical compound of lignin-derived bio-oil to 2-methoxy-4-methylphenol, which is a promising future biofuel. The CoxP@POP exhibited superior catalytic activity and selectivity toward desired product with improved stability compared to the Co3O4@POP. Based on advanced sample characterization results, the extraordinary selectivity of CoxP@POP is attributed to the strong interaction of the cation of the CoxP nanoparticle with the POP matrix and the consequent modifications of the electronic states. Through attenuated total reflectance-infrared spectroscopy, we have also observed different interaction strengths between vanillin and the two catalysts. The decreased catalytic activity of Co3O4@POP compared to CoxP@POP catalyst could be attributed to the stronger adsorption of vanillin over the Co3O4@POP catalyst. Also from kinetic investigation, it is clearly demonstrated that the Co3O4@POP has higher activation energy barrier than the CoxP@POP, which also reflects to the reduction of the overall efficiency of the Co3O4@POP catalyst. To the best of our knowledge, this is the first approach in POP-encapsulated cobalt phosphide catalyst synthesis and comprehensive study in establishing the structure-activity relationship in significant step-forwarding in promoting biomass refining.

Theoretical investigation on the structures, electronic and magnetic properties of new 2D/1D composite nanosystems by adsorbing superhalogen MnCl3 on the BN monolayer/nanoribbons

Hexagonal boron nitride (h-BN), an inorganic analogue of graphene, possesses the remarkable physical and chemical properties and can be viewed as the powerful building block to construct novel composite nanomaterials. In this study, based on the first-principles calculations, we design a new class of hybrid nanosystems by depositing superhalogen MnCl3 on the surface of low-dimensional BN monolayer or nanoribbons (BNML/BNNRs). The large adsorption energies indicate that the MnCl3 can be stably adsorbed on the surface of the BN materials. Regardless of dimension, chirality, ribbon width as well as the adsorption site and coverage of MnCl3, adsorbing MnCl3 can endow these hybrid BN nanomaterials with a large magnetic moment and significantly reduce the robust wide band gap of BN materials to the range of 0.098–0.948 eV. Overall, these new MnCl3–BN composite nanostructures can display the large magnetism and an appropriate band gap, which is very promising to make them an application in the field of multifunctional nanodevices and magnetic materials in the near future.

Temperature Driven Transformation in Dextran-Graft-PNIPAM/Embedded Silver Nanoparticle Hybrid System

During the last decade, stimuli-responsible polymers based on poly(N-isopropylacrylamide) having conformational transition in the range of physiological temperature have been discussed as novel drug delivery nanosystems. A star-like copolymer with a dextran core and grafted poly(N-isopropylacrylamide) arms (D-g-PNIPAM) was synthesized, characterized, and used as a matrix for silver sol preparation. The comparative study of the behavior of individual D-g-PNIPAM and the nanohybrid system D-g-PNIPAM/silver nanoparticles has been done in the temperature range near the lower critical solution temperature (LCST). The methods of Dynamic Light Scattering, small angle X-ray scattering, and UV-VIS absorption spectroscopy have been used. The existence of single nanoparticles and aggregated nanoparticles located in a limited polymer macromolecular volume was established. The increase of the temperature leads to slight aggregation of the silver nanoparticles at the LCST transition. Single nanoparticles do not aggregate with the temperature increase. The thermally induced collapse of end-grafted poly(N-isopropylacrylamide) chains above the LCST do not affect significantly the size characteristics of silver nanoparticles incorporated into the polymer matrix.

Synthesis and characterization of Zn/Al-LDH@SiO2 nanohybrid: Intercalation and release behavior of vitamin C

Layered double hydroxide (LDH) nanoparticles (NPs) have potential applications for the loading and controlled release of drugs. This study investigated the synthesis of Zn/Al-LDH using the co-precipitation and ion-exchange methods, coating with SiO2 NPs and precise control of the release of vitamin C (VC). The results showed that more VC could be loaded by ion exchange. The surface of the VC-loaded LDH NPs was coated with SiO2 using the sol-gel and physical mixing methods. The structure, surface morphology, drug loading and thermostability were characterized and the drug release profile and release kinetics of the intercalated LDHs were studied. It was found that the SiO2 NPs more uniformly coated the LDH surfaces using the sol-gel process than the physical mixing method. The release behavior of VC from the intercalated nanohybrid is well described by the Avrami-Erofe'ev and Elovich models in the slow and fast stages. The sol-gel coated LDH@SiO2 nanohybrid system showed sustained drug delivery compared to the physical mixing method. The overall VC release from LDH increased more than 3-fold after coating with SiO2 NPs. Taken together, the Zn/Al-LDH@SiO2 coated by sol-gel should be considered as a potential sustained-release drug delivery system for VC.

Förster Resonance Energy Transfer Regulated Multicolor Photopatterning from Single Quantum Dot Nanohybrid Films

Precise patterning and localization of functional nanomaterials is the key step for miniaturization and building of optoelectronic devices. Present study utilizes a robust methodology for the multicolor patterning of luminescent Indium Phosphide/Zinc Sulfide Quantum Dot (InP/ZnS QD) film, by taking the advantage of QD’s enhanced photostability over organic dyes. The photoirradiation regulates the composition of donor–acceptor pair, and thereby, the efficiency of Förster Resonance Energy Transfer (EFRET) in QD–dye nanohybrid film. The photopatterned films are reusable over multiple cycles without any compromise of the color clarity, owing to the reversible switching between FRET ON and OFF states. The highlight of the present work is the use of a single QD nanohybrid system to create multicolor luminescent patterns; as opposed to the common practice of using different-colored QDs. FRET assisted photopatterning of luminescent InP/ZnS QD films provides a fundamentally unique and cost-effective approach for the manufacturing of luminescent optoelectronic devices.

Surface modulation of single-walled carbon nanotubes for selective bacterial cell agglutination.

BackgroundBacterial resistance to antibiotics is one of the biggest challenges facing medicine today. Anti-adhesive therapy, using inhibitors of bacterial adhesion to epithelial cells, one of the first stages of infection, is a promising approximation in this area. The size, shape, number of sugar and their placement are variables that have to be taken into account in order to develop multivalent systems able to inhibit the bacterial adhesion based on sugar-lectin interaction.Materials and methodsIn the present work we report a modular approach for the synthesis of water-soluble 1D-carbon nanotube-sugar nanoconstructs, with the necessary flexibility to allow an efficient sugar-lectin interaction. The method is based on the reaction of aryl diazonium salts generated in situ from aniline-substituted mannose and lactose derivatives with single wall carbon nanotubes (SWCNTs) sidewalls.ResultsTwo hybrid nanosystems, I-II, exposing mannose or lactose and having a tetraethylene glycol spacer between the sugar and the nanotube sidewall were rapidly assembled and adequately characterized. The sweet nano-objects were then tested for their ability to agglutinate and selectively inhibit the growth of uropathogenic Escherichia coli. These studies have shown that nanosystem I, exposing mannose on the nanotube surface is able to agglutinate and to inhibit the bacterial growth unlike nano-objects II exposing lactose.ConclusionThe results reported constitute a proof of principle in using mannose-coated 1D-carbon nanotubes as antiadhesive drugs that compete for FimH binding and prevent the uropathogenic bacteria from adhering to the urothelial surface.

PH-responsive carbon nanotube-based hybrid nanogels as the smart anticancer drug carrier

Tumour drug delivery using nanocarriers is attracting ample attentions due to their high drug-loading capacity. Regarding specific tumour microenvironment properties as acidic pH, smart nanocarriers with the ability of responding to the microenvironment, can have a profound effect on the level of drug release and subsequent tumour treatment. In this study, by combining the advantages of multiwall carbon nanotube and pH-sensitive nanogels, multifunctional magneto/pH-responsive nano-hybrid system is developed to deliver the doxorubicin as a general cancer chemotherapeutic drug. The chemical and physical properties of the nanocarrier, as well as drug-loading efficiency and drug releasing characteristics were analysed. It was showed functionalized CNT has low pH-responsiveness in acidic environment, whereas chitosan-coated magnetic nanocomposite can result in greater pH-responsiveness and subsequently higher drug release over a week compared to nanocomposite system without chitosan. This behaviour was proved in Live/Dead assay of the U-87 glioblastoma cell lines exposed to DOX release supernatant at different time intervals so that significant effect of DOX supernatant on cancer cell proliferation suppression was showed.

Multifunctional Nanosystem Based on Graphene Oxide for Synergistic Multistage Tumor-Targeting and Combined Chemo-Photothermal Therapy.

Locating nanomedicines at the active sites plays a pivotal role in the nanoparticle-based cancer therapy field. Herein, a multifunctional nanotherapeutic is designed by using graphene oxide (GO) nanosheets with rich carboxyl groups as the supporter for hyaluronic acid (HA)-methotrexate (MTX) prodrug modification via an adipicdihydrazide cross-linker, achieving synergistic multistage tumor-targeting and combined chemo-photothermal therapy. As a tumor-targeting biomaterial, HA can increase affinity of the nanocarrier toward CD44 receptor for enhanced cellular uptake. MTX, a chemotherapeutic agent, can also serve as a tumor-targeting enhancer toward folate receptor based on its similar structure with folic acid. The prepared nanosystems possess a sheet shape with a dynamic size of approximately 200 nm and pH-responsive drug release. Unexpectedly, the physiological stability of HA-MTX prodrug-decorated GO nanosystems in PBS, serum, and even plasma is more excellent than that of HA-decorated GO nanosystems, while both of them exhibit an enhanced photothermal effect than GO nanosheets. More importantly, because of good blood compatibility as well as reduced undesired interactions with blood components, HA-MTX prodrug-decorated GO nanosystems exhibited remarkably superior accumulation at the tumor sites by passive and active targeting mechanisms, achieving highly effective synergistic chemo-photothermal therapeutic effect upon near-infrared laser irradiation, efficient ablation of tumors, and negligible systemic toxicity. Hence, the HA-MTX prodrug-decorated hybrid nanosystems have a promising potential for synergistic multistage tumor-targeting therapy.

Unveiling Adsorption of Boron Dipyrromethene Conjugated PbS Nanocrystals on Pt Electrode Surface: An Approach Using Electrogenerated Chemiluminescence Spooling Spectra and Multivariate Analysis.

This research focuses on the adsorption and molecular scale communication mechanism of PbS-BDY (BDY, boron dipyrromethene), a nanohybrid system of nanocrystal (NC) and a π-conjugated molecule, investigated through the electrogenerated chemiluminescence (ECL) spooling spectra and multivariate analysis. The results show that the charge transmitted from the excited state of BDY+ to the surface states of PbS NCs leads to emission quenching of BDY and emission enhancement of PbS NCs at 986 nm. Also, the essence tendency of unpassivated sulfur atoms on (100) facets of the PbS NCs acts as a force for adsorption of PbS NCs on the surface of Pt electrode. This phenomenon was proved by conjugation of BDY as an ECL active compound to the PbS NCs and multivariate analysis of augmented data at different scan rates. The obtained results from multivariate analysis reveal that adsorption of PbS-BDY and charge transfer from BDY to surface states of PbS NCs are independent of the scan rate.

Molecular Level Insight into Enhanced n‐Type Transport in Solution‐Printed Hybrid Thermoelectrics

AbstractPerylene diimide (PDI) derivatives hold great promise as stable, solution‐printable n‐type organic thermoelectric materials, but as of yet lack sufficient electrical conductivity to warrant further development. Hybrid PDI‐inorganic nanomaterials have the potential to leverage these physical advantages while simultaneously achieving higher thermoelectric performance. However, lack of molecular level insight precludes design of high performing PDI‐based hybrid thermoelectrics. Herein, the first explicit crystal structure of these materials is reported, providing previously inaccessible insight into the relationship between their structure and thermoelectric properties. Allowing this molecular level insight to drive novel methodologies, simple solution‐based techniques to prepare PDI hybrid thermoelectric inks with up to 20‐fold enhancement in thermoelectric power factor over the pristine molecule (up to 17.5 µW mK−2) is presented. This improved transport is associated with reorganization of organic molecules on the surface of inorganic nanostructures. Additionally, outstanding mechanical flexibility is demonstrated by fabricating solution‐printed thermoelectric modules with innovative folded geometries. This work provides the first direct evidence that packing/organization of organic molecules on inorganic nanosurfaces is the key to effective thermoelectric transport in nanohybrid systems.

Hybrid Nanogels: Stealth and Biocompatible Structures for Drug Delivery Applications.

Considering nanogels, we have focused our attention on hybrid nanosystems for drug delivery and biomedical purposes. The distinctive strength of these structures is the capability to join the properties of nanosystems with the polymeric structures, where versatility is strongly demanded for biomedical applications. Alongside with the therapeutic effect, a non-secondary requirement of the nanosystem is indeed its biocompatibility. The importance to fulfill this aim is not only driven by the priority to reduce, as much as possible, the inflammatory or the immune response of the organism, but also by the need to improve circulation lifetime, biodistribution, and bioavailability of the carried drugs. In this framework, we have therefore gathered the hybrid nanogels specifically designed to increase their biocompatibility, evade the recognition by the immune system, and overcome the self-defense mechanisms present in the bloodstream of the host organism. The works have been essentially organized according to the hybrid morphologies and to the strategies adopted to fulfill these aims: Nanogels combined with nanoparticles or with liposomes, and involving polyethylene glycol chains or zwitterionic polymers.

Surface-Engineered Design of Efficient Luminescent Europium(III) Complex-Based Hydroxyapatite Nanocrystals for Rapid HeLa Cancer Cell Imaging

We synthesized hydroxyapatite nanocrystals under the existence of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)europium(III) (EuTH) complex to form inorganic/organic hybrid nanocrystal (EHA). Then, the folic acid derivative (folate N-hydroxysuccinimidyl ester (FA-NHS)) as the targeting ligand for the HeLa cancer cells was immobilized on the EHA by the mediation of both 3-aminopropyltriethoxysilane and methyltriethoxysilane molecules. Here, we investigated the photofunctions based on the interfacial interactions between the FA-NHS and EHA nanohybrids for preparing the novel bioimaging nanomaterials. As a result, the photofunctions could be changed by the FA-NHS molecular occupancy on the EHA. When the molecular occupancy ratio to the EHA surfaces is at around 3-5%, the intense luminescence from the f-f transition of the Eu3+ ions as well as the charge transfer between the EuTH-FA-NHS was observed to exhibit higher quantum efficiency. Moreover, effective dispersibility in phosphate-buffered saline was confirmed with immobilizing the positively charged FA-NHS. The cytotoxicity against the HeLa cells was also evaluated to verify whether the nanohybrids can be the candidate for cell imaging. The affinity and noncytotoxicity between the FA-NHS-immobilized EHA nanohybrids and cells were monitored for 3 days. Red luminescence from the cells could be observed, and the labels with following the cellular shapes were achieved by an additional culture time of 1 h after injecting the FA-NHS-immobilized EHA nanohybrids to the spheres, indicating the rapid bioimaging process. Therefore, this is the first successful report to describe the synthesis of inorganic-organic nanohybrid systems for controlling the EuTH-FA-NHS interactions. The photofunction of the interfacial interactions was successfully designed to provide "efficient luminescent ability" as well as "rapid targeting to the cancer cells" in one particle.

Effect of the Nature of Nanoparticles and Biocompatible Polymer Stabilizers on the Sizes and Spectral Characteristics of Hybrid Nanosystems

Effect of the Nature of Nanoparticles and Biocompatible Polymer Stabilizers on the Sizes and Spectral Characteristics of Hybrid Nanosystems

Development of ionic liquid-polymer nanoparticle hybrid systems for delivery of poorly soluble drugs

The low solubility and permeability of drugs are two major challenges in the development of delivery systems, thus the aim of this work was to develop ionic liquid-nanocarrier hybrid systems for delivery of poorly soluble drugs. The ionic liquid-nanocarrier hybrid system loading a poorly soluble drug model, rutin, was obtained by a modified double-emulsion technique. The ionic liquids, (2-hydroxyethyl)-trimethylammonium-l-phenylalaninate [Cho][Phe] or (2-hydroxyethyl)-trimethylammonium-l-glutaminate [Cho][Glu] were used, to obtain the systems, at concentrations where cell viability is maintained. The formulation was optimized to obtain carriers with optimal physicochemical features. The hybrid nanosystems had a diameter less than 500 nm, with good polydispersity index and colloidal stability. The association efficiency of the drug ranged between 35 and 50%, which for a poorly soluble drug is a good achievement, and in formulations with pH 6.7 this parameter increased significantly. A robust ionic liquid-polymer nanoparticle hybrid system was obtained in the presence of polyvinyl alcohol at 2% (w/v), demonstrating their potential to incorporate higher amounts of poorly soluble drugs. The developed hybrid systems may ultimately enhance the therapy of several health problems increasing the quality of life of patients treated with this type of drugs.

Hierarchically assembled two-dimensional gold boron nitride-tungsten disulphide nanohybrid interface system for electrobiocatalytic applications

Abstract In this study, we report for the first time, the fabrication of hybrid dual 2D-nanohybrid structure as an interface system for electrochemical biosensing, bioelectronics, and electrobiocatalysis devices through self-assembly combination of gold nanoparticles (AuNPs) with hybrid 2D materials consisting of boron nitride (BN) and tungsten disulphide (WS2). Horseradish peroxidase (HRP) was immobilized on the hybrid dual 2D-nanoparticle system to form a biointerface system. Structural characterization showed high crystallinity in the fabricated structure, while morphological characterization confirmed the high surface area of the hybrid material and the presence of well-dispersed gold nanoparticles (AuNPs). Electrochemical characterization also confirmed that the fabricated HRP/BN/WS2/AuNPs/GC bioelectrode exhibited excellent electron transfer properties at the interface. The electrobiocatalytic activity of the nanohybrid interface structure was studied using hydrogen peroxide (H2O2) as a model analyte. The fabricated bioelectrode exhibited a wide linear range from 0.15 mM to 15.01 mM towards hydrogen peroxide detection with a limit of detection of 3.0 mM (S/N = 3) and a sensitivity of 19.16 μA/mM/cm2. A density functional theory (DFT) calculation was also used to validate the charge transport mobility and conductivity of BN/Au/WS2(001) nanohybrid structure as biosensing interface material. The DFT calculations combined with the experimental studies showed that the BN/Au/WS2(001) nanocomposite enhances the performance of the nanocomposite as sensor due to the introduction new electronic states emanating from the N 2p orbital. This work thus set the stage for the use BN/WS2/AuNPs nanohybrid system as interface material for bioelectronics and biosensing devices fabrications and applications.

Electrochemical Synthesis of Nanohybrid Systems Based on Copper and the Oxide Tungsten Bronzes

A feasibility of obtaining hybrid nanosystems consisting of copper, copper oxides, tetragonal or cubic oxide tungsten bronze (OTB) by means of electrodeposition from the polytungstate melts at 973 and 1023 K was studied. The formation regularities of various hybrid nanosystems were established based on a data of electrochemical techniques, X-ray diffraction phase analysis (XRD), and scanning electron microscopy (SEM). A Cu (mesh)/Cu2O/OTB hybrid system with catalase activity was obtained during electrodeposition from the K2WO4 – Na2WO4 (1: 1) – 50 mol% WO3 melt at 973 K.