Dniel Zmb  Anja Schlosser  Pascal Rusch  Franziska Lübkemann  Julian Koch  Herbert Pfnür  Nadja C. Bigall 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(16)

3D nanoparticle assemblies offer a unique platform to enhance and extend the functionality and optical/electrical properties of individual nanoparticles. Especially, a self‐supported, voluminous, and porous macroscopic material built up from interconnected semiconductor nanoparticles provides new possibilities in the field of sensing, optoelectronics, and photovoltaics. Herein, a method is demonstrated for assembling semiconductor nanoparticle systems containing building blocks possessing different composition, size, shape, and surface ligands. The method is based on the controlled destabilization of the particles triggered by trivalent cations (Y³⁺, Yb³⁺, and Al³⁺). The effect of the cations is investigated via X‐ray photoelectron spectroscopy. The macroscopic, self‐supported aerogels consist of the hyperbranched network of interconnected CdSe/CdS dot‐in‐rods, or CdSe/CdS as well as CdSe/CdTe core‐crown nanoplatelets is used to demonstrate the versatility of the procedure. The non‐oxidative assembly method takes place at room temperature without thermal activation in several hours and preserves the shape and the fluorescence of the building blocks. The assembled nanoparticle network provides longer exciton lifetimes with retained photoluminescence quantum yields, that make these nanostructured materials a perfect platform for novel multifunctional 3D networks in sensing. Various sets of photoelectrochemical measurements on the interconnected semiconductor nanorod structures also reveal the enhanced charge carrier separation.  相似文献   

    

Herbert Canziani  Salvatore Chiera  Thomas Schuffenhauer  Sebastian‐Paul Kopp  Florian Metzger  Andreas Bück  Michael Schmidt  Nicolas Vogel 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(30)

Additive manufacturing promises high flexibility and customized product design. Powder bed fusion processes use a laser to melt a polymer powder at predefined locations and iterate the scheme to build 3D objects. The design of flowable powders is a critical parameter for a successful fabrication process that currently limits the choice of available materials. Here, a bottom‐up process is introduced to fabricate tailored polymer‐ and composite supraparticles for powder‐based additive manufacturing processes by controlled aggregation of colloidal primary particles. These supraparticles exhibit a near‐spherical shape and tailored composition, morphology, and surface roughness. These parameters can be precisely controlled by the mixing and size ratio of the primary particles. Polystyrene/silica composite particles are chosen as a model system to establish structure–property relations connecting shape, morphology, and surface roughness to the adhesion within the powder, which is accessed by tensile strength measurements. The adhesive properties are then connected to powder flowability and it is shown that the resulting powders allow the formation of dense powder films with uniform coverage. Finally, successful powder bed fusion is demonstrated by producing macroscopic single layer specimens with uniform distribution of nanoscale silica additives.  相似文献   

    

Juncheol Lee  Chaeyeon Song  Jimin Lee  Herbert P. Miller  Hasaeam Cho  Bopil Gim  Youli Li  Stuart C. Feinstein  Leslie Wilson  Cyrus R. Safinya  Myung Chul Choi 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(37)

By virtue of their native structures, tubulin dimers are protein building blocks that are naturally preprogrammed to assemble into microtubules (MTs), which are cytoskeletal polymers. Here, polycation‐directed (i.e., electrostatically tunable) assembly of tubulins is demonstrated by conformational changes to the tubulin protofilament in longitudinal and lateral directions, creating tubulin double helices and various tubular architectures. Synchrotron small‐angle X‐ray scattering and transmission electron microscopy reveal a remarkable range of nanoscale assembly structures: single‐ and double‐layered double‐helix tubulin tubules. The phase transitions from MTs to the new assemblies are dependent on the size and concentration of polycations. Two characteristic scales that determine the number of observed phases are the size of polycation compared to the size of tubulin (≈4 nm) and to MT diameter (≈25 nm). This work suggests the feasibility of using polycations that have scissor‐ and glue‐like properties to achieve “programmable breakdown” of protein nanotubes, tearing MTs into double‐stranded tubulins and building up previously undiscovered nanostructures. Importantly, a new role of tubulins is defined as 2D shape‐controllable building blocks for supramolecular architectures. These findings provide insight into the design of protein‐based functional materials, for example, as metallization templates for nanoscale electronic devices, molecular screws, and drug delivery vehicles.  相似文献   

    

Shyam Katnagallu  Ge Wu  Shiv Prakash Singh  Sree Harsha Nandam  Wenzhen Xia  Leigh T. Stephenson  Herbert Gleiter  Ruth Schwaiger  Horst Hahn  Michael Herbig  Dierk Raabe  Baptiste Gault  Shanoob Balachandran 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(39)

The properties of a material can be engineered by manipulating its atomic and chemical architecture. Nanoglasses which have been recently invented and comprise nanosized glassy particles separated by amorphous interfaces, have shown promising properties. A potential way to exploit the structural benefits of nanoglasses and of nanocrystalline materials is to optimize the composition to obtain crystals forming within the glassy particles. Here, a metastable Fe‐10 at% Sc nanoglass is synthesized. A complex hierarchical microstructure is evidenced experimentally at the atomic scale. This bulk material comprises grains of a Fe₉₀Sc₁₀ amorphous matrix separated by an amorphous interfacial network enriched and likely stabilized by hydrogen, and property‐enhancing pure‐Fe nanocrystals self‐assembled within the matrix. This composite structure leads a yield strength above 2.5 GPa with an exceptional quasi‐homogeneous plastic flow of more than 60% in compression. This work opens new pathways to design materials with even superior properties.  相似文献   

    

Prakash Parajuli  Bipin Sharma  Herbert Behlow  Apparao M. Rao 《Advanced Materials Technologies》2020,5(8)

Triboelectric nanogenerators (TENGs) convert mechanical energy, e.g., from human motions, into electrical power. The mechanical force brings two triboelectric materials with different electron affinities into contact, resulting in a voltage that can be used to power a device. Although progress has been made in identifying high‐performance triboelectric materials (e.g., polytetrafluoroethylene, MXenes, polyethylene terephthalate (PET), graphene‐impregnated polymers, and polyimide), the search for better triboelectric materials continues in order to harvest mechanical energy efficiently. Here, it is demonstrated that the output performance of a TENG can be enhanced by coating its triboelectric material surface with an important class of carbons, viz., zero‐dimensional C₆₀ fullerene, which is known for its high electron affinity. Specifically, a C₆₀ fullerene‐based TENG (F‐TENG) is fabricated and evaluated that supports a high open‐circuit voltage of ≈1.6 kV, short‐circuit current of ≈100 µA, instantaneous peak power density of ≈38 W m⁻², and charging of a 1 µF capacitor to 180 V under 8 min. Because of the superior power output of the F‐TENG, a digital watch can be powered continuously in real‐time, a task that cannot be performed with a similar‐sized TENG comprising PET and polyimide. Notably, a novel methodology based on the analysis of the TENG output waveforms is presented for determining the triboelectric charge, which can then be used to rank the electrode material in the tribolelectric series.  相似文献   

    

Bekir Aksoy  Herbert Shea 《Advanced functional materials》2020,30(27)

Programmable soft materials exhibiting dynamically reconfigurable, reversible, fast, and latchable shape transformation are key for applications ranging from wearable tactile actuators to deployable soft robots. Multimorph soft actuator sheets with high load‐bearing capacity are reported, capable of bending on multiple axis, made by combining a single dielectric elastomer actuator (DEA) with two layers of shape memory polymers (SMPs) fibers and an array of stretchable heaters. The rigidity of the SMP fibers can be reduced by two orders of magnitude by Joule heating, thus allowing the orientation and location of soft and hard regions to be dynamically defined by addressing the heaters. When the DEA is then actuated, it bends preferentially along the soft axis, enabling the device to morph into multiple distinct configurations. Cooling down the SMPs locks these shape changes into place. A tip deflection angle of over 300° at 5 kV is achieved with a blocking force of over 27 mN. Devices using two antagonistic DEAs are also reported that attain more complex shapes. Multimorphing is demonstrated by gripping objects with different shapes. An analytical model is developed to determine the design parameters that offers the best trade‐off between large actuation and high holding forces.  相似文献   

    

Herbert De Smet 《Journal of the Society for Information Display》2016,24(2):73-73

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Nadia Abu Samra  Herbert F. Jelinek  Habiba Alsafar  Farah Asghar  Muhieddine Seoud  Shahad M. Hussein  Hisham M. Mubarak  Siddiq Anwar  Mashal Memon  Nariman Afify  Ridda Manzoor  Zahrah Al-Homedi  Wael Osman 《International journal of molecular sciences》2022,23(7)

One of the most common complications during pregnancy is gestational diabetes mellitus (GDM), hyperglycemia that occurs for the first time during pregnancy. The condition is multifactorial, caused by an interaction between genetic, epigenetic, and environmental factors. However, the underlying mechanisms responsible for its pathogenesis remain elusive. Moreover, in contrast to several common metabolic disorders, molecular research in GDM is lagging. It is important to recognize that GDM is still commonly diagnosed during the second trimester of pregnancy using the oral glucose tolerance test (OGGT), at a time when both a fetal and maternal pathophysiology is already present, demonstrating the increased blood glucose levels associated with exacerbated insulin resistance. Therefore, early detection of metabolic changes and associated epigenetic and genetic factors that can lead to an improved prediction of adverse pregnancy outcomes and future cardio-metabolic pathologies in GDM women and their children is imperative. Several genomic and epigenetic approaches have been used to identify the genes, genetic variants, metabolic pathways, and epigenetic modifications involved in GDM to determine its etiology. In this article, we explore these factors as well as how their functional effects may contribute to immediate and future pathologies in women with GDM and their offspring from birth to adulthood. We also discuss how these approaches contribute to the changes in different molecular pathways that contribute to the GDM pathogenesis, with a special focus on the development of insulin resistance.  相似文献   

    

Daniela Grimm  Herbert Schulz  Marcus Krüger  Jos Luis Corts-Snchez  Marcel Egli  Armin Kraus  Jayashree Sahana  Thomas J. Corydon  Ruth Hemmersbach  Petra M. Wise  Manfred Infanger  Markus Wehland 《International journal of molecular sciences》2022,23(6)

Cancer is a disease exhibiting uncontrollable cell growth and spreading to other parts of the organism. It is a heavy, worldwide burden for mankind with high morbidity and mortality. Therefore, groundbreaking research and innovations are necessary. Research in space under microgravity (µg) conditions is a novel approach with the potential to fight cancer and develop future cancer therapies. Space travel is accompanied by adverse effects on our health, and there is a need to counteract these health problems. On the cellular level, studies have shown that real (r-) and simulated (s-) µg impact survival, apoptosis, proliferation, migration, and adhesion as well as the cytoskeleton, the extracellular matrix, focal adhesion, and growth factors in cancer cells. Moreover, the µg-environment induces in vitro 3D tumor models (multicellular spheroids and organoids) with a high potential for preclinical drug targeting, cancer drug development, and studying the processes of cancer progression and metastasis on a molecular level. This review focuses on the effects of r- and s-µg on different types of cells deriving from thyroid, breast, lung, skin, and prostate cancer, as well as tumors of the gastrointestinal tract. In addition, we summarize the current knowledge of the impact of µg on cancerous stem cells. The information demonstrates that µg has become an important new technology for increasing current knowledge of cancer biology.  相似文献   

    

Carolin J. Curtaz  Leonie Reifschlger  Linus Strhle  Jonas Feldheim  Julia J. Feldheim  Constanze Schmitt  Matthias Kiesel  Saskia-Laureen Herbert  Achim Wckel  Patrick Meybohm  Malgorzata Burek 《International journal of molecular sciences》2022,23(7)

Brain metastases are the most severe tumorous spread during breast cancer disease. They are associated with a limited quality of life and a very poor overall survival. A subtype of extracellular vesicles, exosomes, are sequestered by all kinds of cells, including tumor cells, and play a role in cell-cell communication. Exosomes contain, among others, microRNAs (miRs). Exosomes can be taken up by other cells in the body, and their active molecules can affect the cellular process in target cells. Tumor-secreted exosomes can affect the integrity of the blood-brain barrier (BBB) and have an impact on brain metastases forming. Serum samples from healthy donors, breast cancer patients with primary tumors, or with brain, bone, or visceral metastases were used to isolate exosomes and exosomal miRs. Exosomes expressed exosomal markers CD63 and CD9, and their amount did not vary significantly between groups, as shown by Western blot and ELISA. The selected 48 miRs were detected using real-time PCR. Area under the receiver-operating characteristic curve (AUC) was used to evaluate the diagnostic accuracy. We identified two miRs with the potential to serve as prognostic markers for brain metastases. Hsa-miR-576-3p was significantly upregulated, and hsa-miR-130a-3p was significantly downregulated in exosomes from breast cancer patients with cerebral metastases with AUC: 0.705 and 0.699, respectively. Furthermore, correlation of miR levels with tumor markers revealed that hsa-miR-340-5p levels were significantly correlated with the percentage of Ki67-positive tumor cells, while hsa-miR-342-3p levels were inversely correlated with tumor staging. Analysis of the expression levels of miRs in serum exosomes from breast cancer patients has the potential to identify new, non-invasive, blood-borne prognostic molecular markers to predict the potential for brain metastasis in breast cancer. Additional functional analyzes and careful validation of the identified markers are required before their potential future diagnostic use.  相似文献