INMdok (Leibniz Institute for New Materials)
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Nitrogen-Doped Graphene-Like Carbon Intercalated MXene Heterostructure Electrodes for Enhanced Sodium- and Lithium-Ion Storage
Get PDFMXene is investigated as an electrode material for different energy storage systems due to layered structures and metal-like electrical conductivity. Experimental results show MXenes possess excellent cycling performance as anode materials, especially at large current densities. However, the reversible capacity is relatively low, which is a significant barrier to meeting the demands of industrial applications. This work synthesizes N-doped graphene-like carbon (NGC) intercalated Ti3C2Tx (NGC-Ti3C2Tx) van der Waals heterostructure by an in situ method. The as-prepared NGC-Ti3C2Tx van der Waals heterostructure is employed as sodium-ion and lithium-ion battery electrodes. For sodium-ion batteries, a reversible specific capacity of 305 mAh g−1 is achieved at a specific current of 20 mA g−1, 2.3 times higher than that of Ti3C2Tx. For lithium-ion batteries, a reversible capacity of 400 mAh g−1 at a specific current of 20 mA g−1 is 1.5 times higher than that of Ti3C2Tx. Both sodium-ion and lithium-ion batteries made from NGC-Ti3C2Tx shows high cycling stability. The theoretical calculations also verify the remarkable improvement in battery capacity within the NGC-Ti3C2O2 system, attributed to the additional adsorption of working ions at the edge states of NGC. This work offers an innovative way to synthesize a new van der Waals heterostructure and provides a new route to improve the electrochemical performance significantly
Nominal CaAl2Pt2 and Ca2Al3Pt – two new Intermetallic Compounds in the Ternary System Ca−Al−Pt
Get PDFSingle 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
Activation of NF-κB signaling by optogenetic clustering of IKKα and β
Get PDFA large percentage of proteins form higher-order structures in order to fulfill their function. These structures are crucial for the precise spatial and temporal regulation of the cellular signaling network. Investigation of this network requires sophisticated research tools, such as optogenetic tools, that allow dynamic control over the signaling molecules. Cryptochrome 2 and its variations are the best-characterized oligomerizing photoreceptors the optogenetics toolbox has to offer. Therefore, we utilized this switch and combined it with an eGFP-binding nanobody, to build a toolbox of optogenetic constructs that enables the oligomerization of any eGFP-tagged protein of interest. We further introduced the higher clustering variant Cry2olig and an intrinsically disordered region to create higher-order oligomers or phase-separated assemblies to investigate the impact of different oligomerization states on eGFP-tagged signaling molecules. We apply these constructs to cluster IKKα and IKKβ, which resemble the central signaling integrator of the NF-κB pathway, thereby engineer a potent, blue-light-inducible activator of NF-κB signaling
Synthetic intracellular nanostructures enhance cytotoxic T cell function via assembly-driven chemical engineering
Get PDFNature achieves diverse biological functions through structure formation. Inspired by the controlled formation of polypeptide nanostructures in cells, synthetic methods have been developed to assemble artificial nanostructures and organelle-like compartments within living cells. While these synthetic intracellular assemblies have mostly been used to disrupt cellular processes, their potential to induce a gain of function within cells remains unexplored. Here, we introduce redox-sensitive isopeptides that transform into self-assembling linear peptides inside human cytotoxic T cells in response to intracellular levels of glutathione. The in situ formation of synthetic peptide nanostructures in cytotoxic T cells leads to cellular stiffening, establishing a direct interface between biochemically driven peptide assembly and mechanobiological effects. This change in biophysical properties, along with increased phosphorylation of signaling proteins associated with T cell activation, correlates with a significant enhancement in the efficacy of cytotoxic T cells to eliminate cancer cells. Our findings elucidate the cellular impact of synthetic peptide nanostructures assembled within living cytotoxic T cells and demonstrate their ability to modulate and enhance effector immune cell responses
Engineered bacterial therapeutics with material solutions
Get PDFRecent advances in engineered bacterial therapeutics underscore their potential in treating diseases via targeted, live interventions. Despite their promising performance in early clinical phases, no engineered therapeutic bacteria have yet received approval, primarily due to challenges in proving efficacy while ensuring biosafety. Material science innovations, particularly the encapsulation of bacteria within hydrogels, present a promising avenue to enhance bacterial survival, efficacy, and safety in therapeutic applications. This review discusses this interdisciplinary approach to develop living therapeutic materials. Hydrogels not only safeguard the bacteria from harsh physiological conditions but also enable controlled therapeutic release and prevent unintended bacterial dissemination. The strategic use of encapsulation materials could redefine the delivery and functionality of engineered bacterial therapeutics, facilitating their clinical translation
Life After Death: Re-Purposing End-of-Life Supercapacitors for Electrochemical Water Desalination
Get PDFThis study explores the potential of re-purposing end-of-life commercial supercapacitors as electrochemical desalination cells, aligning with circular economy principles. A commercial 500-Farad supercapacitor was disassembled, and its carbon electrodes underwent various degrees of modification. The most straightforward modification involved NaOH-etching of the aluminum current collector to produce free-standing carbon films. More advanced modifications included CO2 activation and binder-added wet processing of the electrodes. When evaluated as electrodes for electrochemical desalination via capacitive deionization of low-salinity (20 mM) NaCl solutions, the minimally modified NaOH-etched carbon electrodes achieved an average desalination capacity of 5.8 mg g−1 and a charge efficiency of 80 %. In contrast, the CO2-activated, wet-processed electrodes demonstrated an improved desalination capacity of 7.9 mg g−1 and a charge efficiency above 90 % with stable performance over 20 cycles. These findings highlight the feasibility and effectiveness of recycling supercapacitors for sustainable water desalination applications, offering a promising avenue for resource recovery and re-purposing in pursuing environmental sustainability
A cell-free, biomimetic hydrogel based on probiotic membrane vesicles ameliorates wound healing
Get PDFProbiotic bacteria, such as Lactobacilli, have been shown to elicit beneficial effects in various tissue regeneration applications. However, their formulation as living bacteria is challenging, and their therapeutic use as proliferating microorganisms is especially limited in immunocompromised patients. Here, we propose a new therapeutic avenue to circumvent these shortcomings by developing a bacteriomimetic hydrogel based on membrane vesicles (MVs) produced by Lactobacilli. We coupled MVs from Lactobacillus plantarum and Lactobacillus casei, respectively, to the surface of synthetic microparticles, and embedded those bacteriomimetics into a pharmaceutically applicable hydrogel matrix. The wound microenvironment changes during the wound healing process, including adaptions of the pH and changes of the oxygen supply. We thus performed proteomic characterization of the MVs harvested under different culture conditions and identified characteristic proteins related to the biological effect of the probiotics in every culture state. In addition, we highlight a number of unique proteins expressed and sorted into the MVs for every culture condition. Using different in vitro models, we demonstrated that increased cell migration and anti-inflammatory effects of the bacteriomimetic microparticles were dependent on the culture condition of the secreting bacteria. Finally, we demonstrated the bacteriomimetic hydrogel's ability to improve healing in an in vivo mouse full-thickness wound model. Our results create a solid basis for the future application of probiotic-derived vesicles in the treatment of inflammatory dispositions and stimulates the initiation of further preclinical trials
Topotaxis of active particles across long distances by sliding along obstacles
Get PDFMany biological active agents respond to gradients of environmental cues by redirecting their motion. In addition to the well-studied prominent examples such as phototaxis and chemotaxis, there has been considerable recent interest in topotaxis, i.e., the ability to sense and follow topographic environmental cues. A trivial topotaxis is achievable through a spatial gradient of obstacle density, though over limited length scales. Here, we introduce a type of topotaxis based on sliding of particles along obstacles—as observed, e.g., in bacterial dynamics near surfaces. We numerically demonstrate how imposing a gradient in the angle of sliding along pillars breaks the spatial symmetry and biases the direction of motion, resulting in an efficient topotaxis in a uniform pillar park. By repeating blocks of pillars with a strong gradient of sliding angle, we propose an efficient method for guiding particles over arbitrary long distances. We provide an explanation for this spectacular phenomenon based on effective reflection at the borders of neighboring blocks. Our results are of technological and medical importance for design of efficient taxis devices for living agents
Towards controlled and simple design of non-enzymatic amperometric sensor for glycerol determination in yeast fermentation medium
Get PDFGlycerol is a widely used signaling bioanalyte in biotechnology. Glycerol can serve as a substrate or product of many metabolic processes in cells. Therefore, quantification of glycerol in fermentation samples with inexpensive, reliable, and rapid sensing systems is of great importance. In this work, an amperometric assay based on one-step designed electroplated functional Pd layers with controlled design was proposed for a rapid and selective measurement of glycerol in yeast fermentation medium. A novel assay utilizing electroplated Pd-sensing layers allows the quantification of glycerol in yeast fermentation medium in the presence of interfering species with RSD below 3% and recoveries ranged from 99 to 103%. The assay requires minimal sample preparation, viz. adjusting of sample pH to 12. The time taken to complete the electrochemical analysis was 3 min. Remarkably, during investigations, it was revealed that sensitivity and selectivity of glycerol determination on Pd sensors were significantly affected by its adsorption and did not depend on the surface structure of sensing layers. This study is expected to contribute to both fundamental and practical research fields related to a preliminary choice of functional sensing layers for specific biotechnology and life science applications in the future
Melt electrowritten poly-lactic acid /nanodiamond scaffolds towards wound-healing patches
Get PDFMultifunctional wound dressings, enriched with biologically active agents for preventing or treating infections and promoting wound healing, along with cell delivery capability, are highly needed. To address this issue, composite scaffolds with potential in wound dressing applications were fabricated in this study. The poly-lactic acid/nanodiamonds (PLA/ND) scaffolds were first printed using melt electrowriting (MEW) and then coated with quaternized β-chitin (QβC). The NDs were well-dispersed in the printed filaments and worked as fillers and bioactive additions to PLA material. Additionally, they improved coating effectiveness due to the interaction between their negative charges (from NDs) and positive charges (from QβC). NDs not only increased the thermal stability of PLA but also benefitted cellular behavior and inhibited the growth of bacteria. Scaffolds coated with QβC increased the effect of bacteria growth inhibition and facilitated the proliferation of human dermal fibroblasts. Additionally, we have observed rapid extracellular matrix (ECM) remodeling on QβC-coated PLA/NDs scaffolds. The scaffolds provided support for cell adhesion and could serve as a valuable tool for delivering cells to chronic wound sites. The proposed PLA/ND scaffold coated with QβC holds great potential for achieving fast healing in various types of wounds