INMdok (Leibniz Institute for New Materials)
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Restoring NK Cell Cytotoxicity Post‐Cryopreservation via Synthetic Cells
Full text linkNatural killer (NK) cells are critical components of the first‐line immune defense, responsible for eliminating tumorigenic cells. NK cell‐based adoptive immunotherapy has gained increasing attention; however, cryopreservation, a standard technique for NK cell storage, significantly impairs NK cell cytotoxicity, particularly in physiological 3D environments. Here, we demonstrate that short‐term co‐culture with effector T cells markedly enhances NK cell motility and killing functionality. Notably, a brief 1‐day co‐culture is sufficient to restore cryopreservation‐impaired NK cell functionality in 3D environments. This enhancement requires direct contact between T cells and NK cells, which facilitates localized high concentrations of IL‐2 at the cell contact sites. To develop a controled, donor‐independent solution, we demonstrate that synthetic T cells with surface‐bound IL‐2 exhibit superior efficiency in revitalizing cryopreserved NK cells. These findings uncover a previously unrecognized role for physical contact‐mediated local IL‐2 signaling and provide an efficient, cost‐effective, and tunable strategy to rescue NK cell functionality post‐cryopreservation, paving the way for more scalable, potent, and clinically viable NK cell‐based immunotherapies
Reflecting on another successful year of Energy Advances
Full text linkAs we turn the page to a new year, it is a fitting moment to reflect on 2024, a year marked by remarkable strides in sustainable energy research and innovation. Energy Advances has been privileged to serve as a platform for groundbreaking studies that aim to address critical global challenges in energy generation, storage, and sustainability. This editorial revisits some of the year’s highlights, celebrates key accomplishments, and looks ahead to the exciting prospects of 2025. In 2024, we were delighted to hold the Energy Advances Editorial Board meeting in person at our London office, Burlington House. The day was filled with exciting discussions about the success and future of the journal. We were also fortunate to have Editorial Board members Matthew Suss, Raymond Wong and Michael Naguib attending in person
Dry Electrode Processing for Free-Standing Supercapacitor Electrodes with Longer Life, Higher Volumetric Outputs, and Reduced Environmental Impact
Full text linkSupercapacitors are efficient and versatile energy storage devices, offering remarkable power density, fast charge/discharge rates, and exceptional cycle life. As research continues to push the boundaries of their performance, electrode fabrication techniques are critical aspects influencing the overall capabilities of supercapacitors. Herein, we aim to shed light on the advantages offered by dry electrode processing for advanced supercapacitors. Notably, our study explores the performance of these electrodes in three different types of electrolytes: organic, ionic liquids, and quasi-solid states. By examining the impact of dry electrode processing on various electrode and electrolyte systems, we show valuable insights into the versatility and efficacy of this technique. The supercapacitors employing dry electrodes demonstrated significant improvements compared with conventional wet electrodes, with a lifespan extension of +45% in organic, +192% in ionic liquids, and +84% in quasi-solid electrolytes. Moreover, the increased electrode densities achievable through the dry approach directly translate to improved volumetric outputs, enhancing energy storage capacities within compact form factors. Notably, dry electrode-prepared supercapacitors outperformed their wet electrode counterparts, exhibiting a higher energy density of 6.1 Wh cm−3 compared with 4.7 Wh cm−3 at a high power density of 195 W cm−3, marking a substantial 28% energy improvement in the quasi-solid electrolyte
Synthesis & Characterization of P3HT-functionalized silver microparticles
Full text linkBackground: An electrofluid is, in essence, a liquid composite composed of a conductive filler material dispersed in a fluid matrix. Electrofluids are a promising area of research with applications in soft electronics as a substitute for conventional solid conductors. The versatility in choice of matrix as well as the inherent properties of a liquid system allow for tuning of mechanical properties such as stiffness as well as overcoming present challenges present in solid conductors such as fatigue or cold working, opening new possibilities for electromechanical applications. It is therefore very interesting to seek ways to control & characterize their rheoelectrical properties.
To this end, the functionalization of the surface of conductive filler particles becomes a promising research topic. By adsorbing or otherwise adding conductive polymers on the surface of filler particles their interaction with the matrix is changed and stability may be improved, most likely at the cost of reduced conductivity. The synthesis and characterization of silver particles functionalized with P3HT (poly(3-hexylthiophene-2,5-diyl)), as well as their comparison to particles functionalized with PTEBS (sodium poly[2-(3-thienyl)-ethoxy-4-butylsulfonate]) has been the main focus of this internship project
Adhäsion und Reibung einzelner DNA-Moleküle
Full text linkDas Verständnis und die Kontrolle der Dynamik von Polymer-Oberflächen-Wechsel- wirkungen sind die Voraussetzung für das Design von Nanoobjekten und für das Verständnis biologischer Prozesse. Wir untersuchen dynamische Reibung und Adhäsion an einer Fest-Flüssig-Grenzfläche mit Hilfe des Rasterkraftmikroskops (AFM). Als Modellsystem wird ein einzelnes M13mp18-DNA-Molekül, mit einer Länge von 2.5 µm, mittels Biotin-Streptavidin-Wechselwirkung über einen Bead an einen Cantilever gebunden. Bei den Adhäsionsmessungen wird der Cantilever mehrfach gen Oberfläche gefahren, wobei er teilweise mehrere hundert Nanometer darüber verweilt, um eine Interaktion zwischen dem Bead und der Oberfläche zu vermeiden. Die Reibungsmessungen werden durchgeführt, indem der Cantilever seitlich parallel zur Oberfläche in einer Höhe von mehreren hundert Nanometern mit unterschiedlichen Geschwindigkeiten bewegt wird. Dies führt zur adhäsiven Wechselwirkung zwischen dem DNA-Molekül an verschiedenen Oberflächen und somit zu einer Verbiegung des Cantilevers. Die verwendeten Oberflächen sind eine mit Cellulosenitrat und Anti-Digoxigenin beschichtete Glasoberfläche, eine positiv geladene poröse Membran und eine mit Poly-L-Lysin beschichteter Glasoberfläche. Das Signal wird unter Berücksichtigung der Abrisskraft, Abrissposition und Frequenz sowie auf mögliche Hotspots bei den Reibungsmessungen analysiert, um typische Wechselwirkungen der DNA mit verschiedenen Oberflächen aufzudecken.Understanding and controlling the dynamics of polymer-surface interactions are key to design nanoscale objects and to understand biological processes. We study dynamic friction and adhesion at the solid-liquid interface by means of atomic force microscopy (AFM) with focus on entanglement dynamics. As a model system, a single M13mp18 DNA-molecule with a length of 2.5 μm is attached via a bead to a cantilever using biotin-streptavidin interaction. Adhesion measurements are performed by approaching and retracting from the surface several times. Partially stopping several hundred nanometers over the surface to avoid the interaction between the bead and the surface. Friction measurements are performed by driving the cantilever laterally in parallel to the surface at a height of several hundred nanometers with different tip velocities. During sliding, the adhesive interaction between the DNA molecule on the AFM tip and different surfaces causes a bending of the cantilever. The used surfaces are a glass surface coated with Nitrocellulose and Anti-Digoxigenin, a positively charged porous membrane and a glass slide coated with Poly-L-Lysine. The signal will be analysed in consideration of the detachment force, position and frequency and possible hotspots for the friction measurements to reveal typical interactions of DNA with different surfaces
Hexaphenyl-1,2-Diphosphonium Dication [Ph3P–PPh3]2+: Superacid, Superoxidant, or Super Reagent?
Full text linkThe oxidation of triphenylphosphine by perfluorinated phenaziniumF aluminate in difluorobenzene affords hexaaryl-1,2-diphosphonium dialuminate 1. Dication 12+ is valence isoelectronic with elusive hexaphenylethane, where instead the formation of a mixture of the trityl radical and Gomberg’s dimer is favored. Quantum-chemical calculations in combination with Raman/IR spectroscopies rationalize the stability of the P–P bonded dimer in 12+ and suggest, akin to the halogens, facile homolytic as well as heterolytic scission. Thus, 12+ serves as a surrogate of both the triphenylphosphorandiylium dication (Ph3P2+) and the triphenylphosphine radical monocation (Ph3P·+). Treating 1 with dimethylaminopyridine (DMAP) or tBu3P replaces triphenylphosphine under heterolytic P–P bond scission. Qualifying as a superoxidant (E vs Fc/Fc+ = +1.44 V), 1 oxidizes trimethylphosphine. Based on halide abstraction experiments (–BF4, –PF6, –SbCl6, –SbF6) as well as the deoxygenation of triethylphosphine oxide, triflate anions as well as toluic acid, 1 also features Lewis superacidity. The controlled hydrolysis affords Hendrickson’s reagent, which itself finds broad use as a dehydration agent. Formally, homolytic P–P bond scission occurs with diphenyldisulfide (PhSSPh) and the triple bonds in benzo- and acetonitrile. The irradiation by light cleaves the P–P bond homolytically and generates transient triphenylphosphine radical cations, which engage in H-atom abstraction as well as CH phosphoranylation
Adaptations of Gram-Negative and Gram-Positive Probiotic Bacteria in Engineered Living Materials
Full text linkEncapsulation of microbes in natural or synthetic matrices is a key aspect of engineered living materials, although the influence of such confinement on microbial behavior is poorly understood. A few recent studies have shown that the spatial confinement and mechanical properties of the encapsulating material significantly influence microbial behavior, including growth, metabolism, and gene expression. However, comparative studies within different bacterial species under identical confinement conditions are limited. In this study, Gram-negative Escherichia coli Nissle 1917 and Gram-positive Lactiplantibacillus plantarum WCFS1 were encapsulated in hydrogel matrices, and their growth, metabolic activity, and recombinant gene expression were examined under varying degrees of hydrogel stiffness, achieved by adjusting the polymer concentration and chemical cross-linking. Both bacteria grow from single cells into confined colonies, but more interestingly, in E. coli gels, mechanical properties influenced colony growth, size, and morphology, whereas this did not occur in L. plantarum gels. However, with both bacteria, increased matrix stiffness led to higher levels of recombinant protein production within the colonies. By measuring metabolic heat from the bacterial gels using the isothermal microcalorimetry technique, it was inferred that E. coli adapts to the mechanical restrictions through multiple metabolic transitions and is significantly affected by the different hydrogel properties. Contrastingly, both of these aspects were not observed with L. plantarum. These results revealed that despite both bacteria being gut-adapted probiotics with similar geometries, mechanical confinement affects them considerably differently. The weaker influence of matrix stiffness on L. plantarum is attributed to its slower growth and thicker cell wall, possibly enabling the generation of higher turgor pressures to overcome restrictive forces under confinement. By providing fundamental insights into the interplay between mechanical forces and bacterial physiology, this work advances our understanding of how matrix properties shape bacterial behavior. The implications of these findings will aid the design of engineered living materials for therapeutic applications
The importance of shape: flakes and spheres in recyclable conductive pastes for printed electronics
Full text linkSilver microflakes and -spheres are common fillers for electrically conductive screen-printing pastes. Here, we report on the effects of filler shapes and sizes on conductivity, sintering, and recyclability. We printed pastes based on flakes and spheres, treated them at 110 °C to 300 °C, and evaluated the electrical conductivity of the resulting layers. The electrical conductivity of the layers treated at 110 °C was dominated by particle–particle contact resistances; flakes yielded layers that were five times more conductive than sphere-based layers due to differences in the particle–particle contact area. Increasing temperature led to a reduction of the resistivity of all layers through sintering. At 300 °C, prints based on spheres were 4 times more conductive than those from flakes. Tomography of the sintered structures showed that the difference was caused by a lower tortuosity factor for spheres. In a final study, we showed that silver flakes and spheres could be recycled after sintering and reused for a new generation of prints without losing electrical performance. The more porous structure of sintered flakes allowed for higher recycling yields compared to spheres. At 140 °C, 91.6% of the flakes and 69.7% of the spheres were recovered as reusable dispersions
A Comparative Study between Thiol-Ene and Acrylate Photocrosslinkable Hyaluronic Acid Hydrogel Inks for Digital Light Processing
Full text linkPhotocrosslinkable formulations based on the radical thiol-ene reaction are considered better alternatives than methacrylated counterparts for light-based fabrication processes. This study quantifies differences between thiol-ene and methacrylated crosslinked hydrogels in terms of precursors stability, the control of the crosslinking process, and the resolution of printed features particularized for hyaluronic acid (HA) inks at concentrations relevant for bioprinting. First, the synthesis of HA functionalized with norbornene, allyl ether, or methacrylate groups with the same molecular weight and comparable degrees of functionalization is presented. The thiol-ene hydrogel precursors show storage stability over 15 months, 3.8 times higher than the methacrylated derivative. Photorheology experiments demonstrate up to 4.7-times faster photocrosslinking. Network formation in photoinitiated thiol-ene HA crosslinking allows higher temporal control than in methacrylated HA, which shows long post-illumination hardening. Using digital light processing, 4% w/v HA hydrogels crosslinked with a dithiol allowed printing of 13.5 × 4 × 1 mm3 layers with holes of 100 µm resolution within 2 s. This is the smallest feature size demonstrated in DLP printing with HA-based thiol-ene hydrogels. The results are important to estimate the extent to which the synthetic effort of introducing –ene functions can pay off in the printing step
Verbundvorhaben InnoLeit - Innovationen in den Markt begleiten - Teilvorhaben: Transferprozess von Materialien und Verfahren in Produktinnovationen
Full text linkZiel des Vorhabens ist es, außeruniversitäre Forschungseinrichtungen dabei zu unterstützen, neue Wege für eine wirtschaftliche Nutzung von Forschungsergebnissen zu entwickeln. Die Begleitung von Forschungsergebnissen in die wirtschaftliche Nutzung ist noch immer von rechtlich-organisatorischen Unklarheiten und Grenzen beschränkt. Das angestrebte Ergebnis ist die Entwicklung von Methoden um die gegenwärtigen rechtlichen Rahmenbedingungen besser zu nutzen und zu gestalten. Ziel ist es, die Transferhandlungsfähigkeit und -sicherheit der beteiligten außeruniversitären Forschungszentren zu erhöhen, indem sie über Wissen verfügen, wie weit sie als Forschungspartner Transfer in den Markt begleiten dürfen. Gleichzeitig soll der Kooperationspartner als Transferempfänger unterstütz werden, Innovationen leichter aufnehmen zu können und im Anschluss selbst marktreif zu machen