Two-dimensional (2D) TaS2 has emerged as a compelling platform for investigating collective electronic phenomena, particularly due to its intricate charge density wave (CDW) phases. To probe nanoscale CDW behavior and superconductivity, the synthesis of high-quality 1T-TaS2 nanocrystals (NCs) is required. In this work, we report for the first time the optimized synthesis of highly crystalline 1T-TaS2 NCs via a thermodynamically optimized chemical vapor transport approach. A comprehensive investigation was conducted to evaluate the influence of key growth parameters, including substrate type (SiO2/Si, c-sapphire, and mica), substrate temperature, growth duration, and transport agent concentration on the resulting crystal morphology and lateral dimensions. Various techniques have been employed to characterize the produced NCs including optical microscopy (OM), atomic force microscopy (AFM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM). Our findings highlight the critical role of the substrate in the growth dynamics and provide a versatile platform for controlled synthesis of the 1T-TaS2 phase, paving the way for its integration into next-generation electronic and quantum technologies.

A novel jacket reference electrode for planar electrochemical sensors is developed as an alternative to designs requiring complex coating techniques. The reference electrode integrates a screen-printed Ag/AgCl element, a PVC housing with an inner electrolyte chamber filled with a mixture of KCl and sodium polyacrylate hydrogel, and a porous membrane as a liquid junction. The jacket reference electrode (jRE) provides controlled ion exchange for reliable electrical contact, long-term moisture retention, and mechanical robustness. Impedance spectroscopy revealed stable junction resistances, even after rehydration following prolonged dry storage. The electrode potential remained stable across varying chloride concentrations. When combined with nitrate-selective electrodes, near-Nernstian responses in calibrations were observed. The jRE was successfully applied to nitrate detection in drinking water and soil, demonstrating a compact, robust, and reproducible platform for potentiometric measurements in complex analytical environments.

Substrate-mediated CVT growth enables highly crystalline 3R-TaSe 2 nanocrystals exhibiting charge density wave behavior at ∼100 K and superconductivity below 2.2 K.

The design of van der Waals (vdW) heterostructures by integrating distinct two-dimensional (2D) materials remains a central strategy for tailoring novel functionalities or enhancing intrinsic properties beyond those of their individual components. In this work, direct epitaxial Bi2Te3/MoS2 vdW heterostructures are synthesized via a sequential chemical vapor transport (CVT) approach. By optimizing the growth parameters, it was observed that the deposition of Bi2Te3 crystals is highly substrate-dependent, with preferential nucleation occurring on MoS2 rather than directly on the sapphire substrate. This selective nucleation may be related to the different surface diffusion characteristics of MoS2 and sapphire. Compared with sapphire, the MoS2 surface provides more favorable diffusion and nucleation conditions for Bi-Te species, promoting preferential lateral growth of Bi2Te3 on MoS2. Furthermore, the lateral size and thickness of Bi2Te3 crystals vary over a broad range as a function of the growth conditions. These findings provide practical insights into parameter-controlled growth of Bi2Te3/MoS2 vdW heterostructures using sequential CVT and highlight their potential for applications in electronic and optoelectronic devices.

DNA origami nanostructures provide programmable control over nanoscale geometry but remain challenging to image due to their low atomic number. Here, we systematically evaluate imaging strategies for both stained and unstained DNA origami deposited on carbon-coated TEM grids. Using Weber contrast as a quantitative metric, we compared different operating modes of (scanning) transmission electron microscopy, (S)TEM, in order to find optimum imaging conditions. STEM was consistently found to deliver the highest contrast, with optimal performance at a camera length of 600 mm towards the high angle annular dark field (HAADF) detector. As expected, the contrast was higher for the thicker three-dimensional nanotubes as compared to DNA 6-helix bundles (6HBs) due to the larger projected thickness of the former. The contrast was effectively enhanced by heavy metal staining with uranyl formate. Notably, 3D molds preserved their designated dimensions upon staining and also largely retained their structural integrity upon complexation with palladium, which also improved the visibility of the structures. These results establish STEM as the optimal approach for high-contrast imaging of DNA origami even of unstained samples and provide practical guidelines for sample preparation and imaging conditions that promote reliable structural visualization.

Niobium disulfide is a member of the metallic two-dimensional layered transition metal dichalcogenides (TMDs) family with a thermodynamically stable 3R-structure. Despite the difficulties involved in controlling the growth of NbS2 crystals with a well-defined structure, a rational approach of bottom-up synthesis of NbS2 nanostructures was performed to achieve this. The parameters of the synthesis by chemical vapor transport (CVT) were derived by thermodynamic simulations of the reaction pathway according to TRAGMIN. High-quality 3R NbS2 nanocrystals were successfully deposited directly on thermal-oxidized Si/SiO2 (100) and thermal-oxidized C-plane sapphire substrates. By using short time vapor transport (0.5 h) and addition of iodine in the temperature range between 600 and 800 degrees C, a thickness down to 7 nm (similar to 12 layers) was achieved. The high-crystallinity morphology of the deposited nanocrystals was confirmed by high-resolution transmission electron microscopy, selected area electron diffraction, and atomic force microscopy as well as double-polarized Raman spectroscopy. Our work explores an important synthesis route to obtain a well-determined phase structure, which is a crucial factor to be considered if practical applications should be realized in the future.

This study investigates the stability and reproducibility of a potentiometric nitrate sensor in all-solid-state configuration, consisting of a screen-printed graphite electrode, coated with electropolymerized polypyrrole as solid contact material, and covered by a TDMA-based ion-selective membrane. Special attention is given to the long-term stability, depending on storage and conditioning conditions as the most important factors for the applicability of the sensor. In particular, regression lines from calibration procedures, performed over a period of up to three months, were analyzed to evaluate the sensor performance. The sensor demonstrated superior stability, with minimal, nearly parallel shifts between regression lines. Notably, the sensor retained its ability to reproduce signals accurately even after one-month periods of dry storage, provided that the applied conditioning period was sufficiently long. The sensor was successfully applied for nitrate detection in drinking water samples, with a reproducibility of ± 3 mg/L, making it a promising candidate for real-time nitrate sensing applications. In all stages of the experiments, the sensor performance was compared with that of an all-solid-state sensor system, consisting of a gold electrode coated with poly(3-octylthiophene-2,5-diyl) and molybdenum disulfide nanocomposites as solid contact material.

Controlling the layer-by-layer chemistry and structure of nanomaterials remains a crucial focus in nanoscience and nanoengineering. Specifically, the integration of atomically thin semiconductors with antiferromagnetic two-dimensional materials holds great promise for advancing research. In this work, we successfully demonstrate a new synthesis approach for high-crystallinity CrCl3/MoS2 van der Waals heterostructures via a thermodynamically optimized chemical vapor transport (CVT) process on c-sapphire (0001) substrates. The 2H-MoS2 layers can be grown as monolayers or with varying twist angles whereas the deposition of CrCl3 layers in a second step forms the well-defined heterostructure. Of particular significance are the sharp and clean edges and faces of the crystals, indicating high-quality interfaces in the heterostructures. Raman spectroscopy, AFM and HRTEM confirm the monocrystalline character and precise structure of these layered nanomaterials, in which their intrinsic properties are preserved and unaffected by strain. This can pave the way for next-generation applications, particularly in valleytronics, opto-spintronics, and quantum information processing.

A ZnO-Graphene oxide nanocomposite (Z-G) was prepared in order to exploit the biomedical features of each component in a single anticancer material. This was achieved by means of an environmentally friendly synthesis, taking place at a low temperature and without the involvement of toxic reagents. The product was physicochemically characterized. The ZnO-to-GO ratio was determined through thermogravimetric analysis, while scanning electron microscopy and transmission electron microscopy were used to provide insight into the morphology of the nanocomposite. Using energy-dispersive X-ray spectroscopy, it was possible to confirm that the graphene flakes were homogeneously coated with ZnO. The crystallite size of the ZnO nanoparticles in the new composite was determined using X-ray powder diffraction. The capacity of Z-G to enhance the toxicity of the anticancer drug Paclitaxel towards breast cancer cells was assessed via a cell viability study, showing the remarkable anticancer activity of the obtained system. Such results support the potential use of Z-G as an anticancer agent in combination with a common chemotherapeutic like Paclitaxel, leading to new chemotherapeutic formulations.

The structural and electrical properties of thin nanocrystals of the 3D topological insulator BiSb(Te1-ySey)(3) (y = 0, 0.01, 0.02, center dot center dot center dot , 0.09) have been investigated. The nanostructures were synthesized from bulk parent BiSb(Te1-ySey)(3) polycrystalline powder on different substrate materials using the bottom-up chemical vapor transport (CVT) method without the addition of transport agents, resulting in well-faceted and thin single crystals with dimensions of similar to 20 mu m in length and similar to 20 nm in height. Thermodynamic calculations were performed to optimize the growth process. The chemical composition and morphology of the nanocrystals were analyzed by energy dispersive X-ray spectroscopy, scanning electron microscopy, and atomic force microscopy. The R (3) over barm crystal structure of individual nanocrystals and their high crystalline quality were studied by high-resolution transmission electron microscopy. Magnetotransport measurements confirm that bulk-charge compensation could be achieved by adding a small amount of Se to the ternary compound BiSbTe3, and the transport properties of thin flakes further reveal the enhanced carrier mobility of topological surface-state carriers.

The world population is continuously increasing. Smart farming is required to keep up with this development by producing more food in a sustainable way. In many new sensor solution developments, the results of the sensor itself is at the target, but the whole solution fails to meet the requirements of the agriculture sensing use cases: the developments suffer from singular approaches with a constricted view solely on the sensor, which might be exchangeable. In this article, we present a holistic approach that can help to overcome these challenges. This approach considers the whole use case, from sense, compute, and connect to power. The approach is discussed with the example of the PLANtAR project, where we develop a soil nitrate sensor and a new leaf wetness and microclimate sensor for application in a greenhouse. The resulting sensor is integrated into a sensor node and compared to a state-of-the-art system. The work shows what is needed to assess the best tradeoffs for agriculture use cases based on a horticulture application.

Zinc oxide/Curcumin (Zn(CUR)O) nanocomposites were prepared via hydrothermal treatment of Zn(NO3)2 in the presence of hexamethylenetetramine as a stabilizing agent and CUR as a bioactive element. Three ZnO : CUR ratios were investigated, namely 57 : 43 (Zn(CUR)O-A), 60 : 40 (Zn(CUR)O-B) and 81 : 19 (Zn(CUR)O-C), as assessed by thermogravimetric analyses, with an average hydrodynamic diameter of nanoaggregates in the range of 223 to 361 nm. The interaction of CUR with ZnO via hydroxyl and ketoenol groups (as proved by X-ray photoelectron spectroscopy analyses) was found to significantly modify the key properties of ZnO nanoparticles with the obtainment of a bilobed shape (as shown by scanning electron microscopy), and influenced the growth process of the composite nanoparticles as indicated by the varying particle sizes determined by powder X-ray diffraction. The efficacy of Zn(CUR)O as anticancer agents was evaluated on MCF-7 and MDA-MB-231 cancer cells, obtaining a synergistic activity with a cell viability depending on the CUR amount within the nanocomposite. Finally, the determination of reactive oxygen species production in the presence of Zn(CUR)O was used as a preliminary evaluation of the mechanism of action of the nanocomposites.

In addition to the classic functions of proteins, such as acting as a biocatalyst or binding partner, the conformational states of proteins and their remodeling upon stimulation need to be considered. A prominent example of a protein that undergoes comprehensive conformational remodeling is transglutaminase 2 (TGase 2), the distinct conformational states of which are closely related to particular functions. Its involvement in various pathophysiological processes, including fibrosis and cancer, motivates the development of theranostic agents, particularly based on inhibitors that are directed toward the transamidase activity. In this context, the ability of such inhibitors to control the conformational dynamics of TGase 2 emerges as an important parameter, and methods to assess this property are in great demand. Herein, we describe the application of the switchSENSE® principle to detect conformational changes caused by three irreversibly binding Nε-acryloyllysine piperazides, which are suitable radiotracer candidates of TGase 2. The switchSENSE® technique is based on DNA levers actuated by alternating electric fields. These levers are immobilized on gold electrodes with one end, and at the other end of the lever, the TGase 2 is covalently bound. A novel computational method is introduced for describing the resulting lever motion to quantify the extent of stimulated conformational TGase 2 changes. Moreover, as a complementary biophysical method, native polyacrylamide gel electrophoresis was performed under similar conditions to validate the results. Both methods prove the occurrence of an irreversible shift in the conformational equilibrium of TGase 2, caused by the binding of the three studied Nε-acryloyllysine piperazides.

The adsorption of heavy metal ions from surface water with ecologically safe and biodegradable biopolymers is increasingly becoming an appealing research challenge. Starch as a biopolymer is exceptionally attractive to solve this problem for its low cost and abundant availability in nature. To expel Ni2+, Fe2+/3+, and Mn2+ from water, we analyzed two native and two oxidized starches, namely potato and corn starch, as bio-adsorbers. The morphology and the surface property of the different starches were studied using SEM. To assess the effectiveness of adsorption onto the starches, we tested three realistic concentrations based on German drinking water ordinance values that were 10-fold, 100-fold, and 1000-fold the limits for Mn2+, Fe2+, and Ni2+, respectively. The concentration of the different ions was measured using the ICP-OES. Furthermore, from subsequent investigations of the adsorption isotherms, we evaluated the adsorption capacities and mechanisms. The adsorption isotherms were fitted using the Langmuir, Sips, and Dubinin–Radushkevich models, whereby Sips showed the highest correlation. Oxidized potato starch achieved viable adsorption capacities of 77 µmol Fe2+/g, 84 µmol Mn2+/g, and 118 µmol Ni2+/g. Investigating the influence of initial swelling in water on the adsorption performance, we found that especially the percentage removal with oxidized starches decreased significantly due to the formation of hydrogen bonds with water molecules at their binding sites with prior swelling.

With the aim of preparing hybrid hydrogels suitable for use as patches for the local treatment of squamous cell carcinoma (SCC)-affected areas, curcumin (CUR) was loaded onto graphene oxide (GO) nanosheets, which were then blended into an alginate hydrogel that was crosslinked by means of calcium ions. The homogeneous incorporation of GO within the polymer network, which was confirmed through morphological investigations, improved the stability of the hybrid system compared to blank hydrogels. The weight loss in the 100–170 °C temperature range was reduced from 30% to 20%, and the degradation of alginate chains shifted to higher temperatures. Moreover, GO enhanced the stability in water media by counteracting the de-crosslinking process of the polymer network. Cell viability assays showed that the loading of CUR (2.5% and 5% by weight) was able to reduce the intrinsic toxicity of GO towards healthy cells, while higher amounts were ineffective due to the antioxidant/prooxidant paradox. Interestingly, the CUR-loaded systems were found to possess a strong cytotoxic effect in SCC cancer cells, and the sustained CUR release (~50% after 96 h) allowed long-term anticancer efficiency to be hypothesized.

Schadstoffe wie Blei und Cadmium kommen in den südlichen Gebirgsregionen von Sachsen geogen in wässrigen Umweltproben stark erhöht vor. Sowohl durch natürliche Auslaugungen als auch durch zusätzliche anthropogene Freisetzungen gelangen relevante Frachten davon in das Grundwasser und in die Oberflächengewässer dieser Region. Das führt teils zu Einstufungen von Wasserkörpern in den schlechten Zustand nach EU-WRRL und zur Verfrachtung wesentlicher Stofffrachten in den Unterlauf der Elbe. Entsprechend der Trinkwasserverordnung (TWVO) betragen die zulässigen Grenzwerte für Cd(II)-Ionen 3 μg/l und für Pb(II)-Ionen 10 μg/l. Für die Erfassung dieser Prozesse und für das Ergreifen von notwendigen Maßnahmen sind systematische Messkampagnen erforderlich. Bisher basierten diese vorrangig auf Laboranalysen. Etablierte Laboranalysenmethoden für die Bestimmung von Metallionen, wie Atomabsorptionsspektrometrie (AAS), induktiv-gekoppeltes Plasma mit optischer Emissionsspektrometrie (engl.: inductively coupled plasma with optical emission spectrometry, ICP-OES) sowie Massenspektrometrie mit induktiv gekoppeltem Plasma (engl.: inductively coupled plasma mass spectrometry, ICP-MS) erfordern jedoch hoch qualifiziertes Personal, eine aufwendige Laborinfrastruktur sowie den Einsatz spezifischer Chemikalien. Sie besitzen außerdem den Nachteil, dass die Analysenergebnisse typischerweise erst mit einem erheblichen Zeitverzug vorliegen, was beispielsweise eine gezielte Reaktion auf eventuelle Sonderfälle unmöglich macht. Die Entwicklung einer kostengünstigen Vor-OrtAnalytik mit feldtauglichen Analysatoren zur In-situÜberwachung des Schadstoffaufkommens in Grundund Oberflächenwässern ist deshalb von großer Wichtigkeit. Durch Vor-Ort-Messungen kann der Aufwand verringert und gleichzeitig die Flexibilität erhöht werden. Dadurch kann ein unmittelbarer Nutzen sowohl bei der behördlichen Arbeit als auch beim Betreiben des aktiven oder des Sanierungsbergbaus gewährleistet werden. Die anodische Stripping-Voltammetrie ermöglicht aufgrund ihrer hohen Empfindlichkeit generell den elektrochemischen Nachweis von Bleiund Cadmiumionen im Spurenbereich [1,2]. Sie kann auch leicht mit kostengünstigen und einfach zu verwendenden Instrumenten gekoppelt werden. Bei der Anreicherung des Analyten an der Arbeitselektrode werden die gelösten Metallionen reduziert. Danach wird das gesamte abgeschiedene Metall wieder in Lösung gebracht, in dem es oxidiert wird, wobei die Arbeitselektrode als Anode fungiert (Abb. 1). Der gemessene Anodenspitzenstrom ist proportional zur Metallkonzentration.

Novel biosensors are incorporating aspects of nanotechnologies, such as the use of functional nanoparticles, in order to increase performance. For the integration of leading edge sensor principles based on nanoparticles, often the precise arrangement of nanostructures is an essential technology. One approach that has been pursued with great success is the template based DNA origami method [1, 2]. The DNA origami can serve as an individual inter-und intramolecular programmable nano-breadboard with a binding point resolution of ~ 5 nm. Our novel, innovative approach uses the DNA origami template to integrate a biological recognition element (DNA aptamer/antibody) centrically in a nanoparticle array to enable an optical detection by surface-enhanced Raman spectroscopy. For high sensor sensitivity despite complex probes, a sufficient signal accumulation is necessary, done by a selective surface immobilization of the biosensor platform. In this way, a high structure density could be realized without overlapping or agglomeration, which would lead to functional damage of the sensor. We introduce a topography supported thin-film system for the selective surface immobilization of the DNA origami and validate them by a parameter variation of a tablet DNA origami structure, which will be the later template of the biosensor platform.

Amyloid fibrils are highly stable and organized peptide or protein structures that on the one hand can cause partially severe diseases such as Alzheimer's disease and on the other hand play fundamental roles during a plethora of biological processes. Nevertheless, there are still plenty open questions concerning their formation. We present a thermophoretic trap which is able to confine the Brownian motion of single amyloid fibrils via temperature gradients. The time-resolved tracking of the fibrils' rotational diffusion coefficients in presence of monomers permits to extract their growth rates or to directly observe secondary growth processes as fragmentation.