Publikationen

Neutrophils play a crucial role in the tumor microenvironment (TME) of head and neck squamous cell carcinomas (HNSCC) and significantly influence treatment outcomes. Phenotypic and functional properties of neutrophils adapt to the TME with distinct subsets modulating disease progression and therapeutic interventions. Here, we evaluated phenotypic and functional differences of neutrophils derived from HNSCC patients and healthy donors. We observed significant phenotypic differences between neutrophils from healthy donors and HNSCC patient-derived neutrophils. Gender and tumor stage influenced neutrophil phenotypes and their ability to lyse tumor cells through antibody-dependent cell-mediated cytotoxicity (ADCC). Patients with advanced HNSCC and males may benefit less from neutrophil-centered immunotherapy. An engineered IgA2 antibody specific for the epidermal growth factor receptor (EGFR) demonstrated superior efficacy in activating neutrophils for ADCC compared to Panitumumab using healthy and patient-derived neutrophils, underscoring the potential of the IgA isotype as a therapeutic alternative. The distinct behavior and antibody-isotype dependent ADCC competence of CD177+/- neutrophils of healthy but not HNSCC donors warrants further exploration. Our study emphasizes the importance of personalized immunotherapy treatments that consider the characteristics of neutrophils, patient demographics, and the type of antibody to improve ADCC and ultimately enhance treatment outcomes for HNSCC.

Silver nanowires (AgNW) find use in transparent conductive electrodes with applications in solar cells, touch screens, and wearables. Unprotected AgNW are prone to atmospheric corrosion and lose conductivity over time. Known passivation techniques either require submersion of pre-deposited AgNW in liquid compounds or the modification of AgNW inks prior to deposition, which alters viscosity and complicates deposition. Here, new possibilities for stabilization of pre-deposited AgNW networks without need for submersion are explored. It is demonstrated that AgNW networks can be stabilized either by argon or hydrogen plasma treatment or by solvent vapor annealing with ethanol, methanol, or ethyl acetate. These treatments yielded stable electrical resistance over at least nine weeks, whereas untreated or thermally annealed AgNW layers quickly lost conductivity. The potential of solvent vapor annealing is further explored by demonstrating a new processing technique for stable polymer matrix composites containing AgNW. Co-deposited layers of AgNW with polystyrene microbeads are annealed in ethyl acetate vapor to stabilize the AgNW while at the same time merging polymer beads into a closed film around the AgNW. The resulting composites maintained stable resistance and transmittance for at least seven weeks.

Recently it was predicted, on the basis of a lattice gas model, that scalar active matter in a gravitational field would rise against gravity up a confining wall or inside a thin capillary—in spite of repulsive particle-wall interactions [Phys. Rev. Lett. 124, 048001 (2020)]. In this paper we confirm this prediction with sedimenting active Brownian particles (ABPs) in a box numerically and elucidate the mechanism leading to the formation of a meniscus rising above the bulk of the sedimentation region. The height of the meniscus increases with the activity of the system, algebraically with the Péclet number. The formation of the meniscus is determined by a stationary circular particle current, a vortex, centered at the base of the meniscus, whose size and strength increase with the ABP activity. The origin of these vortices can be traced back to the confinement of the ABPs in a box: already the stationary state of ideal (noninteracting) ABPs without gravitation displays circular currents that arrange in a highly symmetric way in the eight octants of the box. Gravitation distorts this vortex configuration downward, leaving two major vortices at the two side walls, with a strong downward flow along the walls. Repulsive interactions between the ABPs change this situation only as soon as motility induced phase separation (MIPS) sets in and forms a dense, sedimented liquid region at the bottom, which pushes the center of the vortex upwards towards the liquid-gas interface. Self-propelled particles therefore represent an impressive realization of scalar active matter that forms stationary particle currents being able to perform visible work against gravity or any other external field, which we predict to be observable experimentally in active colloids under gravitation.

Many 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.

Hybrid hydrogels are hydrogels that exhibit heterogeneity in the network architecture by means of chemical composition and/or microstructure. The different types of interactions, together with structural heterogeneity, which can be created on different length scales, determine the mechanical properties of the final material to a large extent. In this work, the microstructure–mechanical property relationships for a hybrid hydrogel that contains both electrostatic and covalent interactions are investigated. The hybrid hydrogel is composed of a microphase-separated polyelectrolyte complex network (PEC) made of poly(4-styrenesulfonate) and poly(diallyldimethylammonium chloride) within a soft and elastic polyacrylamide hydrogel network. The system exhibits a granular structure, which is attributed to the liquid–liquid phase separation into complex coacervate droplets induced by the polymerization and the subsequent crowding effect of the polyacrylamide chains. The coacervate droplets are further hardened into PEC granules upon desalting the hydrogel. The structure formation is confirmed by a combination of electron microscopic imaging and molecular dynamics simulations. The interpenetration of both networks is shown to enhance the toughness of the resulting hydrogels due to the dissipative behavior of the PEC through the rupture of electrostatic interactions. Upon cyclic loading–unloading, the hydrogels show recovery of up to 80% of their original dissipative behavior in less than 300 s of rest with limited plasticity. The granular architecture and the tough and self-recoverable properties of the designed hybrid networks make them good candidates for applications, such as shape-memory materials, actuators, biological tissue mimics, and elastic substrates for soft sensors.

We study the effect of additives on the colloidal stability of alkanethiol-coated gold nanoparticles. Cyclic amines and sulfides of different sizes were added to dispersions in decane at additive concentrations below 128 mM. Small-angle X-ray scattering (SAXS) indicated that tetrahydrothiophene reduced the agglomeration temperature, Tagglo, by up to 29 °C, a considerable increase in colloidal stability. Amines had a much weaker stabilizing effect of up to 2.5 °C. We found an unexpected maximum of stabilization for low additive concentrations, where Tagglo increased at concentrations above 64 mM. Molecular dynamics simulations were used to correlate these observations with the ligand shell structure. They excluded the physisorption of additives as a stabilization mechanism and suggested that sulfides replace hexadecanethiol on the AuNP surfaces by chemisorption. This hinders ligand ordering, thereby reducing Tagglo, which explains the stabilizing effect. Clustering of chemisorbed additive molecules at high concentration restabilized the ligand ordered state, explaining the detrimental effect of higher additive concentrations. The predictions of the simulations were confirmed by using thermogravimetric analyses and SAXS measurements of washed samples that indicated that the structure of the ligand shell itself, not the presence of physisorbed additives, changes Tagglo. Finally, we calculated potentials of mean force, which show that larger sulfide-based additives have a weaker affinity for the gold surface than smaller ones due to stronger steric hindrance. This explains why smaller cyclic sulfides were the most efficient stabilizers.

Pulmonary fibrosis, a disabling lung disease, results from the fibrotic transformation of lung tissue. This fibrotic transformation leads to a deterioration of lung capacity, resulting in significant respiratory distress and a reduction in overall quality of life. Currently, the frontline treatment of pulmonary fibrosis remains limited, focusing primarily on symptom relief and slowing disease progression. Bacterial infections with Pseudomonas aeruginosa are contributing to a severe progression of idiopathic pulmonary fibrosis. Phytic acid, a natural chelator of zinc, which is essential for the activation of metalloproteinase enzymes involved in pulmonary fibrosis, shows potential inhibition of LasB, a virulence factor in P. aeruginosa, and mammalian metalloproteases (MMPs). In addition, phytic acid has anti-inflammatory properties believed to result from its ability to capture free radicals, inhibit certain inflammatory enzymes and proteins, and reduce the production of inflammatory cytokines, key signaling molecules that promote inflammation. To achieve higher local concentrations in the deep lung, phytic acid was spray dried into an inhalable powder. Challenges due to its hygroscopic and low melting (25 °C) nature were mitigated by converting it to sodium phytate to improve crystallinity and powder characteristics. The addition of leucine improved aerodynamic properties and reduced agglomeration, while mannitol served as carrier matrix. Size variation was achieved by modifying process parameters and were evaluated by tools such as the Next Generation Impactor (NGI), light diffraction methods, and scanning electron microscopy (SEM). An inhibition assay for human MMP-1 (collagenase-1) and MMP-2 (gelatinase A) allowed estimation of the biological effect on tissue remodeling enzymes. The activity was also assessed with respect to inhibition of bacterial LasB. The formulated phytic acid demonstrated an IC50 of 109.7 µg/mL for LasB with viabilities > 80 % up to 188 µg/mL on A549 cells. Therefore, inhalation therapy with phytic acid-based powder shows promise as a treatment for early-stage Pseudomonas-induced pulmonary fibrosis.

The expansion of T cells ex vivo is crucial for effective immunotherapy but currently limited by a lack of expansion approaches that closely mimic in vivo T cell activation. Taking inspiration from bottom-up synthetic biology, a new synthetic cell technology is introduced based on dispersed liquid-liquid phase-separated droplet-supported lipid bilayers (dsLBs) with tunable biochemical and biophysical characteristics, as artificial antigen presenting cells (aAPCs) for ex vivo T cell expansion. These findings obtained with the dsLB technology reveal three key insights: first, introducing laterally mobile stimulatory ligands on soft aAPCs promotes expansion of IL-4/IL-10 secreting regulatory CD8+ T cells, with a PD-1 negative phenotype, less prone to immune suppression. Second, it is demonstrated that lateral ligand mobility can mask differential T cell activation observed on substrates of varying stiffness. Third, dsLBs are applied to reveal a mechanosensitive component in bispecific Her2/CD3 T cell engager-mediated T cell activation. Based on these three insights, lateral ligand mobility, alongside receptor- and mechanosignaling, is proposed to be considered as a third crucial dimension for the design of ex vivo T cell expansion technologies.

Zhu et al. introduce MELG (materials engineered by living grafting), combining engineered microbes with non-living scaffolds for functional protein regeneration within. These MELGs can be used for long-term controlled release, enzyme-mediated biocatalysis, and DNA purification. This approach offers enhanced functionality and durability in bioactive materials compared to traditional non-living counterparts.

Background: Tumor cells release extracellular vesicles (EVs) that contribute to the polarization of macrophages towards tumor-associated macrophages (TAMs). High expression levels of the RNA binding protein IGF2BP2/IMP2 are correlated with increased tumor cell proliferation, invasion, and poor prognosis in the clinic. However, there is a lack of understanding of whether IMP2 affects the cargo of cancer cell-derived EVs, thereby modulating macrophage polarization.
Methods: EVs were isolated from IMP2-expressing HCT116 parental cells (WT) and CRISPR/Cas9 IMP2 knockout (KO) cells. EVs were characterized according to MISEV guidelines, microRNA cargo was assessed by microRNA-Seq, and the protein cargo was analyzed by proteomics. Primary human monocyte-derived macrophages (HMDMs) were polarized by EVs, and the expression of genes and surface markers was assessed using qPCR and flow cytometry, respectively. Morphological changes of macrophages, as well as the migratory potential of cancer cells, were assessed by the Incucyte® system and macrophage matrix degradation potential by zymography. Changes in the metabolic activity of macrophages were quantified using a Seahorse® analyzer. For in vivo studies, EVs were injected into the yolk sac of zebrafish larvae, and macrophages were isolated by fluorescence-activated cell sorting.
Results: EVs from WT and KO cells had a similar size and concentration and were positive for 25 vesicle markers. The expression of tumor-promoting genes was higher in macrophages polarized with WT EVs than KO EVs, while the expression of TNF and IL6 was reduced. A similar pattern was observed in macrophages from zebrafish larvae treated in vivo. WT EV-polarized macrophages showed a higher abundance of TAM-like surface markers, higher matrix degrading activity, as well as a higher promotion of cancer cell migration. MicroRNA-Seq revealed a significant difference in the microRNA composition of WT and KO EVs, particularly a high abundance of miR-181a-5p in WT EVs, which was absent in KO EVs. Inhibitors of macropinocytosis and phagocytosis antagonized the delivery of miR-181a-5p into macrophages and the downregulation of the miR-181a-5p target DUSP6. Proteomics data showed differences in protein cargo in KO vs. WT EVs, with the differentially abundant proteins mainly involved in metabolic pathways. WT EV-treated macrophages exhibited a higher basal oxygen consumption rate and a lower extracellular acidification rate than KO EV-treated cells.
Conclusion: Our results show that IMP2 determines the cargo of EVs released by cancer cells, thereby modulating the EVs' actions on macrophages. Expression of IMP2 is linked to the secretion of EVs that polarize macrophages towards a tumor-promoting phenotype.