Publikationen

Developing thin, freestanding electrodes that work simultaneously as a current collector and electroactive material is pivotal to integrating portable and wearable chemical sensors. Herein, we have synthesized graphene/Prussian blue (PB) electrodes for hydrogen peroxide detection (H2O2) using a two-step method. First, an reduced graphene oxide/PAni/Fe2O3 freestanding film is prepared using a doctor blade technique, followed by the electrochemical deposition of PB nanoparticles over the films. The iron oxide nanoparticles work as the iron source for the heterogeneous electrochemical deposition of the nanoparticles in a ferricyanide solution. The size of the PB cubes electrodeposited over the graphene-based electrodes was controlled by the number of voltammetric cycles. For H2O2 sensing, the PB10 electrode achieved the lowest detection and quantification limits, 2.00 and 7.00 μM, respectively. The findings herein evidence the balance between the structure of the graphene/PB-based electrodes with the electrochemical performance for H2O2 detection and pave the path for developing new freestanding electrodes for chemical sensors.

The unsustainable dependence of nitrogen fertilizers (NFs) production on energy-intensive processes and its association with nitrate-laden wastewater that fuels harmful algal blooms (HABs) necessitate innovative solutions. Here, we propose a paradigm shift: repurposing HABs biomass as carbon-based catalysts (Cu1Mo1/NC) for the ambient-condition electrosynthesis of NFs from NO3− and CO2. Remarkably, Cu1Mo1/NC delivers a high NFs yield rate of 2303 μg h−1 mgcat−1 (772 μg h−1mgcat−1 for urea and 1531 μg h−1 mgcat−1 for ammonia) with a Faradaic efficiency (FE) of 68.4% (15.2% for urea and 53.2% for ammonia) at −1.05 V vs. RHE. Experimental and theoretical evidence reveal that Cu doping tunes the d-band center of Cu1Mo1/NC, bringing it closer to the Fermi level. This enhances the intermediate adsorption, thereby propelling the C-N coupling reaction. Carbon reduction potential analysis underscores the promising feasibility and sustainable value of the presented method.

Herein, we report polyphosphonate covalent organic frameworks (COFs) constructed via P-O-P linkages. The materials are synthesized via a single-step condensation reaction of the charge-assisted hydrogen-bonded organic framework, which is constructed from phenylphosphonic acid and 5,10,15,20‐tetrakis[p‐phenylphosphonic acid]porphyrin and is formed by simply heating its hydrogen-bonded precursor without using chemical reagents. Above 210 °C, it becomes an amorphous microporous polymeric structure due to the oligomerization of P-O-P bonds, which could be shown by constant-time solid-state double-quantum 31P nuclear magnetic resonance experiments. The polyphosphonate COF exhibits good water and water vapor stability during the gas sorption measurements, and electrochemical stability in 0.5 M Na2SO4 electrolyte in water. The reported family of COFs fills a significant gap in the literature by providing stable microporous COFs suitable for use in water and electrolytes. Additionally, we provide a sustainable synthesis route for the COF synthesis. The narrow pores of the COF effectively capture CO2.

Single crystals of CaAl2Pt2, Ca2Al3Pt and Ca2AlPt2 were initially observed in an attempt to synthesize Ca3Al4Pt4. Their structures were determined using single-crystal X-ray diffraction experiments. While nominal CaAl2Pt2 (CaBe2Ge2 type, P4/nmm, a=426.79(2), c=988.79(6) pm, wR2=0.0679, 246 F2 values and 18 variables) and Ca2Al3Pt (Mg2Cu3Si type, P63/mmc, a=561.46(5), c=876.94(8) pm, wR2=0.0664, 214 F2 values and 13 variables) exhibit Al/Pt mixing, for Ca2AlPt2 (Ca2Ir2Si type, C2/c, a=981.03(2) b=573.74(1), c=772.95(2) pm, β=101.862(1)° wR2=0.0307, 2246 F2 values and 25 variables) no mixing was observed. Subsequently, the nominal compositions were targeted with synthetic attempts from the elements using arc-melting and annealing techniques. For CaAl2Pt2 and Ca2Al3Pt always multi-phase mixtures were observed while Ca2AlPt2 could be obtained as almost X-ray pure material. Quantum-chemical calculations were used to investigate the charge transfer in these compounds rendering them polar intermetallics with a designated [AlxPty]δ− polyanion and Caδ+ cations in the cavities of the polyanions.

The fundamental question of how forces are generated in a motile cell, a lamellipodium, and a comet tail is the subject of this note. It is now well established that cellular motility results from the polymerization of actin, the most abundant protein in eukaryotic cells, into an interconnected set of filaments. We portray this process in a continuum mechanics framework, claiming that polymerization promotes a mechanical swelling in a narrow zone around the nucleation loci, which ultimately results in cellular or bacterial motility. To this aim, a new paradigm in continuum multi-physics has been designed, departing from the well-known theory of Larché–Cahn chemo-transport-mechanics. In this note, we set up the theory of network growth and compare the outcomes of numerical simulations with experimental evidence.

Cobaltocenium-containing polymers, an emerging class of materials, have historically been challenging to prepare due to their chemical robustness. In this work, we introduce a novel and highly efficient method for their preparation based on methacrylate-containing block copolymers (BCPs), allowing segment-selective introduction of functional moieties. The catalyst-free and quantitative hydroamination reaction we introduce has proven successful for the post-modification of amine-containing polymers with cobaltocenium. To demonstrate the versatility of this method, we successfully synthesized a series of BCPs consisting of polystyrene and a 5 to 20 wt% poly(tert-butyl aminoethyl methacrylate) (PtBAEMA) segment by living anionic polymerization. The selective functionalization with ethynyl-cobaltocenium hexafluorophosphate results in adjustable 5 to 40 wt% cobaltocenium units in the polymer as part of the PtBAEMA block segment. The success was monitored by IR spectroscopy, and the quantitative incorporation of the cobaltocenium moiety was verified by 1H NMR, UV-Vis spectroscopy, and TGA. DSC proved the block-selective cobaltocenium introduction by an additional glass transition temperature at 154 °C, and the strong microphase separation character of the amphiphilic BCPs leads to lamellar structures in the bulk state, as proven by TEM investigations. Finally, the water contact angle on polymer films is compared, showing polarity inversion and tunability upon conversion of hydrophilic amine to hydrophobic cobaltocenium hexafluorophosphate moieties. This successful synthesis and characterization of cobaltocenium-containing BCPs not only paves the way for a new class of metallopolymers but also offers functionalization possibilities for a variety of other responsive moieties, providing access to functional BCPs.

Histone deacetylases (HDACs) are enzymes that play crucial roles in cellular processes by hydrolyzing acetyl-L-lysine side chains in core histones, thereby regulating gene expression and maintaining homeostasis. Histone deacetylase inhibitors (HDACi) have emerged as promising agents, particularly in cancer treatment, due to their ability to induce cytotoxic and pro-apoptotic effects. Selective HDAC6 inhibitors, such as ITF3756, have shown low off-target toxicity and promising pharmacological activities, but their poor water solubility limits their application in nanoparticulate drug delivery systems. Here, we optimized a nanostructured lipid carrier (NLC) formulation for delivering ITF3756 using the design of experiments (DOE) and response surface methodology (RSM). An interaction between the factor surfactant and formulation volume was observed, thus demonstrating that the surfactant concentration impacts the NLC size. It can be speculated that the higher the amount of the drug in the formulation, the lower the polydispersion index (PDI), thus resulting in more stable nanostructures. The optimized ITF3756-NLC demonstrated a size of 51.1 ± 0.3 nm, 8.85 ± 4.71 mV charge, and high entrapment efficiency (EE%), maintaining stability for 60 days. Moreover, ITF3756-NLC enhanced α-tubulin acetylation in melanoma, lung, and brain cancer cell lines, indicating retained or improved bioactivity. The ITF3756-NLC formulation offers a viable approach for enhancing the bioavailability and therapeutic efficacy of HDAC6 inhibitors, demonstrating potential for clinical applications in cancer immunotherapy.

Carbon-based materials are cost-effective and eco-friendly but have limited sensitivity for detecting heavy metals. Density Functional Theory (DFT) is employed to design materials suitable for sensing, based on their interaction with analytes. Oxidized carbon black embedded with silver nanoparticles (OCB-Ag) is designed and studied via DFT, showing promising conductivity and arsenic interaction. Experimental validation confirmed its efficacy. The OCB-Ag nanocomposite was synthesized via in-situ preparation and used as an electrode material for arsenic detection. Characterization via UV–Visible spectroscopy and X-ray diffraction confirmed successful synthesis. Electrochemical interaction with arsenite was studied using square wave anodic stripping voltammetry. The OCB-Ag platform exhibited a linear current response up to 600 ppm of As3+, with a low limit of detection (0.01 ppm) and good sensitivity (5.9 µA ppm−1). The detection limit of electrode material for As3+ lies within the threshold value set by world health organization for drinking water. The experimental results validated the concept of designing electrochemical sensing platform through DFT, and its potential for detection of As3+.

Flexible and stretchable electronics require both sensing elements and stretching-insensitive electrical connections. Conductive polymer composites and liquid metals are highly deformable but change their conductivity upon elongation and/or contain rare metals. Solid conductive composites are limited in mechanoelectrical properties and are often combined with macroscopic Kirigami structures, but their use is limited by geometrical restraints. Here, we introduce “Electrofluids”, concentrated conductive particle suspensions with transient particle contacts that flow under shear that bridge the gap between classic solid composites and liquid metals. We show how Carbon Black (CB) forms large agglomerates when using incompatible solvents that reduce the electrical percolation threshold by 1 order of magnitude compared to more compatible solvents, where CB is well-dispersed. We analyze the correlation between stiffness and electrical conductivity to create a figure of merit of first electrofluids. Sealed elastomeric tubes containing different types of electrofluids were characterized under uniaxial tensile strain, and their electrical resistance was monitored. We found a dependency of the piezoresistivity with the solvent compatibility. Electrofluids enable the rational design of sustainable soft electronics components by simple solvent choice and can be used both as sensor and electrode materials, as we demonstrate.

The cobalt sulfide (CoS2) and nickel cobaltite (NiCo2O4) nanostructures are individually prepared and layered one over the other in reverse order to explore their effects on energy storage applications. The physicochemical characterization is conducted using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The water contact angle of these nanostructures is also measured to assess their affinity toward aqueous electrolytes. The electrochemical performance and the contribution from surface-limited to diffusion-limited charge storage are measured. Among all the prepared nanostructures, cobalt sulfide grown over nickel cobaltite (CS/NCO) exhibited the highest specific capacity of 508.6 mAh⸳g−1 at a specific current of 1 A⸳g−1 using three electrode system. The same electrode demonstrated the highest specific power of 115.1 W⸳kg−1 in combination with a specific energy of 226.4 Wh⸳kg−1. Moreover, asymmetric device was also fabricated that exhibited maximum specific capacity of 49.8 mAh⸳g−1 at the specific current of 1 A⸳g−1, and specific energy of 93.0 Wh⸳kg−1 at specific power of 774.8 W⸳kg−1. The specific capacity of the full cell is retained up to 78.9 % after 5000 cycles. The post-electrochemical evaluation of CS/NCO is performed and the outcomes suggested that fabricated CS/NCO‖AC has promising future in the energy storage applications. Additionally, It is proposed that reversing the growth order of nanostructures in a hybrid electrode material is a potential pathway to optimize its electrochemical performance for energy storage applications.