Ultrasmall Cu2‐xS Nanodots for Highly Efficient Photoacoustic Imaging‐Guided Photothermal Therapy

Monodisperse, ultrasmall (<5 nm) Cu_2?xS nanodots (u‐Cu_2?xS NDs) with significantly strong near‐infrared absorption and conversion are successfully demonstrated for effective deep‐tissue photoacoustic imaging‐guided photothermal therapy both in vitro and in vivo. Owing to ultrasmall nanoparticle size and high water dispersibility as well as long stability, such nanodots possess a prolonged circulation in blood and good passive accumulation within tumors through the enhanced permeability and retention effect. These u‐Cu_2?xS NDs have negligible side effects to both blood and normal tissues according to in vivo toxicity evaluations for up to 3 months, showing excellent hemo/histocompatibility. Furthermore, these u‐Cu_2?xS NDs can be thoroughly cleared through feces and urine within 5 days, showing high biosafety for further potential clinical translation. This novel photoacoustic imaging‐guided photothermal therapy based on u‐Cu_2?xS NDs composed of a single component shows great prospects as a multifunctional nanoplatform with integration and multifunction for cancer diagnosis and therapy.     

Cactus‐Like Hollow Cu2‐xS@Ru Nanoplates as Excellent and Robust Electrocatalysts for the Alkaline Hydrogen Evolution Reaction

The development of Pt‐free electrocatalysts for the hydrogen evolution reaction (HER) recently is a focus of great interest. While several strategies are developed to control the structural properties of non‐Pt catalysts and boost their electrocatalytic activities for the HER, the generation of highly reactive defects or interfaces by combining a metal with other metals, or with metal oxides/sulfides, can lead to notably enhanced catalytic performance. Herein, the preparation of cactus‐like hollow Cu_2‐x S@Ru nanoplates (NPs) that contain metal/metal sulfide heterojunctions and show excellent catalytic activity and durability for the HER in alkaline media is reported. The initial formation of Ru islands on presynthesized Cu_1.94S NPs, via cation exchange between three Cu⁺ ions and one Ru³⁺, induces the growth of the Ru phase, which is concomitant with the dissolution of the Cu_1.94S nanotemplate, culminating in the formation of a hollow nanostructure with numerous thin Ru pillars. Hollow Cu_2‐x S@Ru NPs exhibit a small overpotential of 82 mV at a current density of ?10 mA cm^?2 and a low Tafel slope of 48 mV dec^?1 under alkaline conditions; this catalyst is among state‐of‐the‐art HER electrocatalysts in alkaline media. The excellent performance of hollow Cu_2‐x S@Ru NPs originates from the facile dissociation of water in the Volmer step.     

Bioinspired Multivalent Peptide Nanotubes for Sialic Acid Targeting and Imaging‐Guided Treatment of Metastatic Melanoma

Tumor metastasis is considered a major cause of cancer‐related human mortalities. However, it still remains a formidable challenge in clinics. Herein, a bioinspired multivalent nanoplatform for the highly effective treatment of the metastatic melanoma is reported. The versatile nanoplatform is designed by integrating indocyanine green and a chemotherapeutic drug (7‐ethyl‐10‐hydroxycamptothecin) into phenylboronic acid (PBA)‐functionalized peptide nanotubes (termed as I/S‐PPNTs). I/S‐PPNTs precisely target tumor cells through multivalent interaction between PBA and overexpressed sialic acid on the tumor surface in order to achieve imaging‐guided combination therapy. It is demonstrated that I/S‐PPNTs are efficiently internalized by the B16‐F10 melanoma cells in vitro in a PBA grafting density–dependent manner. It is further shown that I/S‐PPNTs specifically accumulate and deeply penetrate into both the subcutaneous and lung metastatic B16‐F10 melanoma tumors. More importantly, I/S‐PPNT‐mediated combination chemo‐ and photodynamic therapy efficiently eradicates tumor and suppresses the lung metastasis of B16‐F10 melanoma in an immunocompetent C57BL/6 mouse model. The results highlight the promising potential of the multivalent peptide nanotubes for active tumor targeting and imaging‐guided cancer therapy.     

Nitrogen‐Doped Carbon Nanotube Confined Co–Nx Sites for Selective Hydrogenation of Biomass‐Derived Compounds

Biomass is the most abundant renewable resource on earth and developing high‐performance nonprecious selective hydrogenation (SH) catalysts will enable the use of biomass to replace rapidly diminishing fossil resources. This work utilizes ZIF‐67‐derived nitrogen‐doped carbon nanotubes to confine Co nanoparticles (NPs) with Co–N_x active sites as a high‐performance SH catalyst. The confined Co NPs with Co–N_x exhibit excellent catalytic activity, selectivity, and stability toward a wide range of biomass‐derived compounds. Such active sites can selectively hydrogenate aldehyde, ketone, carboxyl, and nitro groups of biomass‐derived compounds into value‐added fine chemicals with 100% selectivity. The reported approach could be adopted to create other forms of catalytically active sites from other nonprecious metals.     

Amorphous Ruthenium‐Sulfide with Isolated Catalytic Sites for Pt‐Like Electrocatalytic Hydrogen Production Over Whole pH Range

Electrocatalytic hydrogen evolution reaction (HER) is an efficient way to generate hydrogen fuel for the storage of renewable energy. Currently, the widely used Pt‐based catalysts suffer from high costs and limited electrochemical stability; therefore, developing an efficient alternative catalyst is very urgent. Herein, one pot hydrothermal synthesis is reported of amorphous ruthenium‐sulfide (RuS_x) nanoparticles (NPs) supported on sulfur‐doped graphene oxide (GO). The as‐obtained composite serves as a Pt‐like HER electrocatalyst. Achieving a current density of ?10 mA cm^?2 only requires a small overpotential (?31, ?46, and ?58 mV in acidic, neutral, and alkaline electrolyte, respectively) with high durability. The isolated Ru active site inducing Volmer–Heyrovsky mechanism in the RuS_x NPs is demonstrated by the Tafel analysis and X‐ray absorption spectroscopy characterization. Theoretical simulation indicates the isolated Ru site exhibits Pt‐like Gibbs free energy of hydrogen adsorption (?0.21 eV) therefore generating high intrinsic HER activity. Moreover, the strong bonding between the RuS_x and S–GO, as well as pH tolerance of RuS_x are believed to contribute to the high stability. This work shows a new insight for amorphous materials and provides alternative opportunities in designing advanced electrocatalysts with low‐cost for HER in the hydrogen economy.     

A Simple and Scalable Route to Synthesize CoxCu1−xCo2O4@CoyCu1−yCo2O4 Yolk–Shell Microspheres,A High‐Performance Catalyst to Hydrolyze Ammonia Borane for Hydrogen Production

Yolk–shell structured micro/nano‐sized materials have broad and important applications in different areas due to their unique spatial configurations. In this study, yolk–shell structured Co₃O₄@Co₃O₄ is prepared using a simple and scalable hydrothermal reaction, followed by a calcination process. Then, Co_xCu_1?xCo₂O₄@Co_yCu_1?yCo₂O₄ microspheres are synthesized via adsorption and calcination processes using the as‐prepared Co₃O₄@Co₃O₄ as the precursor. A possible formation mechanism of the yolk–shell structures is proposed based on the characterization results, which is different from those of yolk–shell structures in previous study. For the first time, the catalytic activity of yolk–shell structured catalysts in ammonia borane (AB) hydrolysis is studied. It is discovered that the yolk–shell structured Co_xCu_1?xCo₂O₄@Co_yCu_1?yCo₂O₄ microspheres exhibit high performance with a turnover frequency (TOF) of 81.8 mol_hydrogen min^?1 mol_cat^?1. This is one of the highest TOF values reported for a noble‐metal‐free catalyst in the literature. Additionally, the yolk–shell structured Co_xCu_1?xCo₂O₄@Co_yCu_1?yCo₂O₄ microspheres are highly stable and reusable. These yolk–shell structured Co_xCu_1?xCo₂O₄@Co_yCu_1?yCo₂O₄ microsphere is a promising catalyst candidate in AB hydrolysis considering the excellent catalytic behavior and low cost.     

Au Nanoclusters Sensitized Black TiO2−x Nanotubes for Enhanced Photodynamic Therapy Driven by Near‐Infrared Light

The low reactive oxygen species production capability and the shallow tissue penetration of excited light (UV) are still two barriers in photodynamic therapy (PDT). Here, Au cluster anchored black anatase TiO_2?x nanotubes (abbreviated as Au₂₅/B‐TiO_2?x NTs) are synthesized by gaseous reduction of anatase TiO₂ NTs and subsequent deposition of noble metal. The Au₂₅/B‐TiO_2?x NTs with thickness of about 2 nm exhibit excellent PDT performance. The reduction process increased the density of Ti³⁺ on the surface of TiO₂, which effectively depresses the recombination of electron and hole. Furthermore, after modification of Au₂₅ nanoclusters, the PDT efficiency is further enhanced owing to the changed electrical distribution in the composite, which forms a shallow potential well on the metal–TiO₂ interface to further hamper the recombination of electron and hole. Especially, the reduction of anatase TiO₂ can expend the light response range (UV) of TiO₂ to the visible and even near infrared (NIR) light region with high tissue penetration depth. When excited by NIR light, the nanoplatform shows markedly improved therapeutic efficacy attributed to the photocatalytic synergistic effect, and promotes separation or restrained recombination of electron and hole, which is verified by experimental results in vitro and in vivo.     

Flexible Broadband Graphene Photodetectors Enhanced by Plasmonic Cu3−xP Colloidal Nanocrystals

The integration of graphene with colloidal quantum dots (QDs) that have tunable light absorption affords new opportunities for optoelectronic applications as such a hybrid system solves the problem of both quantity and mobility of photocarriers. In this work, a hybrid system comprising of monolayer graphene and self‐doped colloidal copper phosphide (Cu_3?x P) QDs is developed for efficient broadband photodetection. Unlike conventional PbS QDs that are toxic, Cu_3?x P QDs are environmental friendly and have plasmonic resonant absorption in near‐infrared (NIR) wavelength. The half‐covered graphene with Cu_3?x P nanocrystals (NCs) behaves as a self‐driven p–n junction and shows durable photoresponse in NIR range. A comparison experiment reveals that the surface ligand attached to Cu_3?x P NCs plays a key role in determining the charge transfer efficiency from Cu_3?x P to graphene. The most efficient three‐terminal photodetectors based on graphene‐Cu_3?x P exhibit broadband photoresponse from 400 to 1550 nm with an ultrahigh responsivity (1.59 × 10⁵ A W^?1) and high photoconductive gain (6.66 × 10⁵) at visible wavelength (405 nm), and a good responsivity of 9.34 A W^?1 at 1550 nm. The demonstration of flexible graphene‐Cu_3?x P photodetectors operated at NIR wavelengths may find potential applications in optical sensing, biological imaging, and wearable devices.     

Boost antimicrobial effect of CTAB-capped NixCu1−xO (0.0 ≤ x ≤ 0.05) nanoparticles by reformed optical and dielectric characters

Chemical doping and coating have been considered as efficient semiconductor physics strategies to modulate the physical, chemical, and biological properties of materials for the required applications. In this study, cetyltrimethylammonium bromide (CTAB) stabilizer-capped nickel-doped cupric oxide (Ni_xCu_1?xO) nanoparticles (NPs) with different doping concentrations (0.0?≤?x?≤?0.05) were synthesized via a one-step rapid and low-cost solvothermal synthesis route. The as-synthesized CTAB-capped Ni_xCu_1?xO NPs have been sightseen for their structural/morphological, optical/dielectric, and antimicrobial properties using XRD/SEM/TEM, FT-IR/UV–visible/Impedance spectroscopies, and Agar well diffusion method, respectively. Relevant results show enhanced optical, dielectric and antimicrobial properties with Ni doping due to the smaller size effect. Importantly, in vitro examination, the antimicrobial activity of the grown NPs was evaluated against four microbial species, exhibits that the CTAB-capped Ni-doped CuO NPs possess a command antimicrobial toxicity to Staphylococcus aureus (25923-ATCC), Klebsiella pneumoniae (700603-ATCC), and Escherichia coli (25922-ATCC) and an intermediate performance towards Candida albicans (24433-ATCC). The minimum inhibitory concentration (MIC) assay for the obtained CTAB-Ni_0.05Cu_0.95O sample upon S. aureus or K. pneumoniae pathogens reaches extremely as low as 5 μg ml^?1 for all reported CuO NPs. The improved dose-dependent antimicrobial effect has been found to be strongly dependent on the particle size, surface morphology, elemental compositions, and surface bio-functionality of the catalytic nanomaterials. Additionally, Ni-dopant, CTAB-stabilizer, and binding of Cu⁺/Cu²⁺ ions with respiratory enzymes collectively produce an excess amount of reactive oxygen species (ROS) in the bacterial culture medium, which determines a predominant antibacterial mechanism for bacterial cells damage. Overall, these inorganic (Ni_xCu_1?xO) NPs with antimicrobial cationic surfactant (CTAB) have advantages to use as a functionalized disinfection nanoagent to control the microbial infections in the healthcare sector together with various electronic and photonic medical diagnoses.

Graphical abstract

     

Chiral CuxOS@ZIF-8 Nanostructures for Ultrasensitive Quantification of Hydrogen Sulfide In Vivo

In this study, a Cu_xOS@ZIF-8 nanostructure is fabricated to quantify the levels of hydrogen sulfide (H₂S) in living cells and in vivo. Zeolitic lmidazolate framework-8 (ZIF-8) is chosen as an encapsulation shell to improve the selectivity of this probe. Using this unique nanostructure, ultrasensitive quantification and bioimaging of H₂S in living cells are successfully achieved. The lower limit of detection is 0.8 and 5.3 nmol per 10⁶ cells for circular dichroism and fluorescence modes, respectively. It is found that the chiral Cu_xOS NPs transformed into achiral Cu_xS NPs contribute to the ultrasensitive detection. Notably, this probe can also be carried out to detect and track H₂S levels in tumor-bearing animals. The discoveries put forward for the creation of a detection platform for quantitative tracking and analysis in clinic.     

Chemical solution deposition of YBa2Cu3O7−x coated conductors

At present, the development of superconducting YBa₂Cu₃O_7−x coated conductors attracts much attention due to their enormous application potential in electric power systems. Worldwide research is focused on the investigation and improvement of buffer materials and YBa₂Cu₃O_7−x superconducting properties as well as low-cost manufacturing processes in cooperation with industrial companies. Accordingly, chemical solution deposition has emerged as a highly competitive, versatile, and cost-effective technique for fabricating coated conductors of high performance. New chemical solution approaches are under development for buffer layer deposition. In order to achieve high critical current carrying YBa₂Cu₃O_7−x layers, the established trifluoroacetate route is favored. This paper reviews the most recent work on chemical solution deposition within the IFW Dresden while also considering achievements on this specific research topic worldwide.     

Engineering Bimetallic Ag–Cu Nanoalloys for Highly Efficient Oxygen Reduction Catalysts: A Guideline for Designing Ag‐Based Electrocatalysts with Activity Comparable to Pt/C‐20%

Development of highly active and stable Pt‐free oxygen reduction reaction catalysts from earth‐abundant elements remains a grand challenge for highly demanded metal–air batteries. Ag‐based alloys have many advantages over platinum group catalysts due to their low cost, high stability, and acceptable oxygen reduction reaction (ORR) performance in alkaline solutions. Nevertheless, compared to commercial Pt/C‐20%, their catalytic activity still cannot meet the demand of commercialization. In this study, a kind of catalysts screening strategy on Ag_x Cu_100?x nanoalloys is reported, containing the surface modification method, studies of activity enhancement mechanism, and applied research on zinc–air batteries. The results exhibit that the role of selective dealloying (DE) or galvanic displacement (GD) is limited by the “parting limitation”, and this “parting limitation” determines the surface topography, position of d‐band center, and ORR performance of Ag_x Cu_100?x alloys. The GD‐Ag₅₅Cu₄₅ and DE‐Ag₂₅Cu₇₅ catalysts alloys present excellent ORR performance that is comparable to Pt/C‐20%. The relationship between electronic perturbation and specific activity demonstrates that positive shift of the d‐band center (≈0.12 eV, relative to Ag) for GD‐Ag₅₅Cu₄₅ is beneficial for ORR, which is contrary to Pt‐based alloys (negative shift, ≈0.1 eV). Meanwhile, extensive electrochemical and electronic structure characterization indicates that the high work function of GD‐Ag₅₅Cu₄₅ (4.8 eV) is the reason behind their excellent durability for zinc–air batteries.     

All in one theranostic nanoplatform enables efficient anti-tumor peptide delivery for triple-modal imaging guided cancer therapy

Developing a reliable system to efficiently and safely deliver peptide drugs into tumor tissues still remains a great challenge since the instability of peptide drugs and low ability to traverse the cell membrane. Herein, we constructed a multifunctional nanoplatform based on porous europium/gadolinium (Eu/Gd)-doped NaLa(MoO₄)₂ nanoparticles (NLM NPs) to deliver antitumor peptide of B-cell lymphoma/leukemia-2-like protein 11 (BIM) for cancer therapy. The porous NLM NPs exhibited inherent photoluminescent, magnetic and X-ray absorbable properties, which enable them for triple-modal bioimaging, including fluorescence, magnetic resonance imaging (MRI) and computed tomography (CT). This triple-modal bioimaging can contribute to monitoring NLM NPs biodistribution and guiding therapy in vitro and in vivo. Furthermore, the NLM NPs showed negligible cytotoxicity in vitro and tissue toxicity in vivo. Importantly, NLM NPs could load the antitumor peptide of BIM and efficiently improve the resistance of peptide drugs to proteolysis. The BIM peptide was efficiently delivered into the tumor cells by NLM NPs, which can inhibit the growth and promote the apoptosis of cancer cells in vitro, significantly inhibit the tumor growth in vivo. Notably, NLM-BIM theranostic nanoplatform exhibits low systemic toxicity and fewer side effects in vivo. The NLM NPs can serve as a promising multifunctional peptide delivery nanoplatform for multi-modal bioimaging and cancer therapy.

     

pH‐Dependent Galvanic Replacement of Supported and Colloidal Cu2O Nanocrystals with Gold and Palladium

Galvanic replacement reactions (GRRs) on nanoparticles (NPs) are typically performed between two metals, i.e., a solid metal NP and a replacing salt solution of a more noble metal. The solution pH in GRRs is commonly considered an irrelevant parameter. Yet, the solution pH plays a major role in GRRs involving metal oxide NPs. Here, Cu₂O nanocrystals (NCs) are studied as galvanic replacement (GR) precursors, undergoing replacement by gold and palladium, with the resulting nanostructures showing a strong dependence on the pH of the replacing metal salt solution. GRRs are reported for the first time on supported (chemically deposited) oxide NCs and the results are compared with those obtained with corresponding colloidal systems. Control of the pH enables production of different nanostructures, from metal‐decorated Cu₂O NCs to uniformly coated Cu₂O‐in‐metal (Cu₂O@Me) core–shell nanoarchitectures. Improved metal nucleation efficiencies at low pHs are attributed to changes in the Cu₂O surface charge resulting from protonation of the oxide surface. GR followed by etching of the Cu₂O cores provides metal nanocages that collapse upon drying; the latter is prevented using a sol–gel silica overlayer stabilizing the metal nanocages. Metal‐replaced Cu₂O NCs and their corresponding stabilized nanostructures may be useful as photocatalysts, electrocatalysts, and nanosensors.     

High‐Performance Li–SeSx All‐Solid‐State Lithium Batteries

All‐solid‐state Li–S batteries are promising candidates for next‐generation energy‐storage systems considering their high energy density and high safety. However, their development is hindered by the sluggish electrochemical kinetics and low S utilization due to high interfacial resistance and the electronic insulating nature of S. Herein, Se is introduced into S cathodes by forming SeS_x solid solutions to modify the electronic and ionic conductivities and ultimately enhance cathode utilization in all‐solid‐state lithium batteries (ASSLBs). Theoretical calculations confirm the redistribution of electron densities after introducing Se. The interfacial ionic conductivities of all achieved SeS_x–Li₃PS₄ (x = 3, 2, 1, and 0.33) composites are 10^?6 S cm^?1. Stable and highly reversible SeS_x cathodes for sulfide‐based ASSLBs can be developed. Surprisingly, the SeS₂/Li₁₀GeP₂S₁₂–Li₃PS₄/Li solid‐state cells exhibit excellent performance and deliver a high capacity over 1100 mAh g^?1 (98.5% of its theoretical capacity) at 50 mA g^?1 and remained highly stable for 100 cycles. Moreover, high loading cells can achieve high areal capacities up to 12.6 mAh cm^?2. This research deepens the understanding of Se–S solid solution chemistry in ASSLB systems and offers a new strategy to achieve high‐performance S‐based cathodes for application in ASSLBs.     

Earth‐Abundant Chalcogenide Photovoltaic Devices with over 5% Efficiency Based on a Cu2BaSn(S,Se)4 Absorber

In recent years, Cu₂ZnSn(S,Se)₄ (CZTSSe) materials have enabled important progress in associated thin‐film photovoltaic (PV) technology, while avoiding scarce and/or toxic metals; however, cationic disorder and associated band tailing fundamentally limit device performance. Cu₂BaSnS₄ (CBTS) has recently been proposed as a prospective alternative large bandgap (~2 eV), environmentally friendly PV material, with ~2% power conversion efficiency (PCE) already demonstrated in corresponding devices. In this study, a two‐step process (i.e., precursor sputter deposition followed by successive sulfurization/selenization) yields high‐quality nominally pinhole‐free films with large (>1 µm) grains of selenium‐incorporated (x = 3) Cu₂BaSnS_4?x Se_x (CBTSSe) for high‐efficiency PV devices. By incorporating Se in the sulfide film, absorber layers with 1.55 eV bandgap, ideal for single‐junction PV, have been achieved within the CBTSSe trigonal structural family. The abrupt transition in quantum efficiency data for wavelengths above the absorption edge, coupled with a strong sharp photoluminescence feature, confirms the relative absence of band tailing in CBTSSe compared to CZTSSe. For the first time, by combining bandgap tuning with an air‐annealing step, a CBTSSe‐based PV device with 5.2% PCE (total area 0.425 cm²) is reported, >2.5× better than the previous champion pure sulfide device. These results suggest substantial promise for the emerging Se‐rich Cu₂BaSnS_4–x Se_x family for high‐efficiency and earth‐abundant PV.     

Detection of β‐Amyloid by Sialic Acid Coated Bovine Serum Albumin Magnetic Nanoparticles in a Mouse Model of Alzheimer's Disease

The accumulation and formation of β‐amyloid (Aβ) plaques in the brain are distinctive pathological hallmarks of Alzheimer's disease (AD). Designing nanoparticle (NP) contrast agents capable of binding with Aβ highly selectively can potentially facilitate early detection of AD. However, a significant obstacle is the blood brain barrier (BBB), which can preclude the entrance of NPs into the brain for Aβ binding. In this work, bovine serum albumin (BSA) coated NPs are decorated with sialic acid (NP‐BSA_x‐Sia) to overcome the challenges in Aβ imaging in vivo. The NP‐BSA_x‐Sia is biocompatible with high magnetic relaxivities, suggesting that they are suitable contrast agents for magnetic resonance imaging (MRI). The NP‐BSA_x‐Sia binds with Aβ in a sialic acid dependent manner with high selectivities toward Aβ deposited on brains and cross the BBB in an in vitro model. The abilities of these NPs to detect Aβ in vivo in human AD transgenic mice by MRI are evaluated without the need to coinject mannitol to increase BBB permeability. T₂*‐weighted MRI shows that Aβ plaques in mouse brains can be detected as aided by NP‐BSA_x‐Sia, which is confirmed by histological analysis. Thus, NP‐BSA_x‐Sia is a promising new tool for noninvasive in vivo detection of Aβ plaques.     

Intelligent Nanocomposites with Intrinsic Blood–Brain‐Barrier Crossing Ability Designed for Highly Specific MR Imaging and Sonodynamic Therapy of Glioblastoma

The blood–brain barrier (BBB) is the most important obstacle to improving the clinical outcomes of diagnosis and therapy of glioblastoma. Thus, the development of a novel nanoplatform that can efficiently traverse the BBB and achieve both precise diagnosis and therapy is of great importance. Herein, an intelligent nanoplatform based on holo‐transferrin (holo‐Tf) with in situ growth of MnO₂ nanocrystals is constructed via a reformative mild biomineralization process. Furthermore, protoporphyrin (ppIX), acting as a sonosensitizer, is then conjugated into holo‐Tf to obtain MnO₂@Tf‐ppIX nanoparticles (TMP). Because of the functional inheritance of holo‐Tf during fabrication, TMP can effectively traverse the BBB for highly specific magnetic resonance (MR) imaging of orthotopic glioblastoma. Clear suppression of tumor growth in a C6 tumor xenograft model is achieved via sonodynamic therapy. Importantly, the experiments also indicate that the TMP nanoplatform has satisfactory biocompatibility and biosafety, which favors potential clinical translation.     

Electron diffraction study of the ordering process in Cu2−xS

The formation of the ordered phase of Cu_2?xS (x=0.2) and its structural transformations were investigated. It is shown that the ordered Cu_2?xS phase is formed from face-centred cubic (f.c.c.)Cu_2?xS as a result of a phase transition which is caused by copper enrichment during heat treatment at temperatures in the range 100–300°C. The ordered phase exists in the temperature range from room temperature to 300°C. This phase transforms reversibly to the f.c.c. phase at about 300°C. Compositional changes occur on further heat treatment of the ordered phase and lead to the irreversible transformation of Cu_2?xS to the hexagonal modification of Cu₂S.     

Resistive Switching of Individual,Chemically Synthesized TiO2 Nanoparticles

Resistively switching devices are considered promising for next‐generation nonvolatile random‐access memories. Today, such memories are fabricated by means of “top–down approaches” applying thin films sandwiched between nanoscaled electrodes. In contrast, this work presents a “bottom–up approach” disclosing for the first time the resistive switching (RS) of individual TiO₂ nanoparticles (NPs). The NPs, which have sizes of 80 and 350 nm, respectively, are obtained by wet chemical synthesis and thermally treated under oxidizing or vacuum conditions for crystallization, respectively. These NPs are deposited on a Pt/Ir bottom electrode and individual NPs are electrically characterized by means of a nanomanipulator system in situ, in a scanning electron microscope. While amorphous NPs and calcined NPs reveal no switching hysteresis, a very interesting behavior is found for the vacuum‐annealed, crystalline TiO_2–x NPs. These NPs reveal forming‐free RS behavior, dominantly complementary switching (CS) and, to a small degree, bipolar switching (BS) characteristics. In contrast, similarly vacuum‐annealed TiO₂ thin films grown by atomic layer deposition show standard BS behavior under the same conditions. The interesting CS behavior of the TiO_2–x NPs is attributed to the formation of a core–shell‐like structure by re‐oxidation of the reduced NPs as a unique feature.