Reactive precursor particles as synthetic platform for the generation of functional nanoparticles, nanogels, and microgels

Precise control of the chemical functionality of polymer nanoparticles is a key requirement in tailoring their (dynamic) colloidal properties toward advanced applications. However, current synthetic techniques are still limited in the versatility of chemical design and preparation of such functional colloidal nanomaterials. Two major challenges remain: First, various particle preparation methods are restricted in their functional group tolerance, thus hindering certain combinations of polymer backbones with specific functional groups. Second, the preparation of particles with different functionalities requires the synthesis of different particle batches. But this often results in a simultaneous variation of colloidal features. As a result, the accurate determination of important structure–property relations is still hindered. To address these restrictions, postmodification of preformed reactive particles is gaining more attention. This technique has evolved from polymer synthesis, where postpolymerization functionalization enables the introduction of a plethora of functional groups without changing the degree of polymerization and the molecular weight distribution. Similarly, modifying precursor particles enables the introduction of functional groups into particles while reducing variations in colloidal features, e.g., particle size and size distribution. This powerful synthetic method complements established procedures for functionalization of particle surfaces, thereby enabling the facile preparation of (multi‐)functional particle libraries, which will allow precise investigations of structure–property relations

Nantes – Avenue de la Piaudière

Le diagnostic de l’avenue de la Piaudière a été réalisé sur un terrain d’une emprise de 9 547 m2, localisé entre la route de Vertou et la Sèvre Nantaise. Le secteur d’étude, encore partiellement bâti et soumis à plusieurs contraintes (zone boisée classée, déblais de démolition, pollution), a été diagnostiqué à hauteur de 5,17 %. Les neuf sondages ont permis de mettre au jour une carrière qui s’étage sur une longueur d’environ 170 m depuis la route de Vertou au nord-est vers la rivière en cont..

IEST: WASSA-2018 Implicit Emotions Shared Task

Past shared tasks on emotions use data with both overt expressions of emotions (I am so happy to see you!) as well as subtle expressions where the emotions have to be inferred, for instance from event descriptions. Further, most datasets do not focus on the cause or the stimulus of the emotion. Here, for the first time, we propose a shared task where systems have to predict the emotions in a large automatically labeled dataset of tweets without access to words denoting emotions. Based on this intention, we call this the Implicit Emotion Shared Task (IEST) because the systems have to infer the emotion mostly from the context. Every tweet has an occurrence of an explicit emotion word that is masked. The tweets are collected in a manner such that they are likely to include a description of the cause of the emotion - the stimulus. Altogether, 30 teams submitted results which range from macro F1 scores of 21 % to 71 %. The baseline (MaxEnt bag of words and bigrams) obtains an F1 score of 60 % which was available to the participants during the development phase. A study with human annotators suggests that automatic methods outperform human predictions, possibly by honing into subtle textual clues not used by humans. Corpora, resources, and results are available at the shared task website at http://implicitemotions.wassa2018.com.Comment: Accepted at Proceedings of the 9th Workshop on Computational Approaches to Subjectivity, Sentiment and Social Media Analysi

Dual-reactive nanogels for orthogonal functionalization of hydrophilic shell and amphiphilic network

Amphiphilic nanogels (NGs) combine a soft, water-swollen hydrogel matrix with internal hydrophobic domains. While these domains can encapsulate hydrophobic cargoes, the amphiphilic particle surface can reduce colloidal stability and/or limit biological half-life. Therefore, a functional hydrophilic shell is needed to shield the amphiphilic network and tune interactions with biological systems. To adjust core and shell properties independently, we developed a synthetic strategy that uses preformed dual-reactive nanogels. In a first step, emulsion copolymerization of pentafluorophenyl methacrylate (PFPMA) and a reduction-cleavable crosslinker produced precursor particles for subsequent network modification. Orthogonal shell reactivity was installed by using an amphiphilic block copolymer (BCP) surfactant during this particle preparation step. Here, the hydrophilic block poly(polyethylene glycol methyl ether methacrylate) (PPEGMA) contains a reactive alkyne end group for successive functionalization. The hydrophobic block (P(PFPMA-co-MAPMA) contains random methacryl-amido propyl methacrylamide (MAPMA) units to covalently attach the surfactant to the growing PPFPMA network. In the second step, orthogonal modification of the core and shell was demonstrated. Network functionalization with combinations of hydrophilic (acidic, neutral, or basic) and hydrophobic (cholesterol) groups gave a library of pH- and redox-sensitive amphiphilic NGs. Stimuli-responsive properties were demonstrated by pH-dependent swelling and reduction-induced degradation via dynamic light scattering. Subsequently, copper-catalyzed azide–alkyne cycloaddition was used to attach azide-modified rhodamine as model compound to the shell (followed by UV-Vis). Overall, this strategy provides a versatile platform to develop multi-functional amphiphilic nanogels as carriers for hydrophobic cargoes

Zur Wirkung des Seeanemonen Toxins II (ATX-II) auf spannungsgesteuerte Natriumionenkanäle neuronaler Zellen und zu den dadurch erreichten Änderungen im Schmerzempfinden

ATX-II wurde ursprünglich aus dem Gift der Seeanemone Anemonia sulcata isoliert und ist als potenter Aktivator spannungsgesteuerter Natriumionenkanäle (Navs) bekannt, da es einen persistierenden Na+-Strom induziert. Vor Kurzem wurden bestimmte Nav Subtypen mit menschlichem Schmerz in Verbindung gebracht. Somit liegt es nahe, dass detaillierte Kenntnisse über die Regulierung von Navs für die Entwicklung neuer Pharmaka im Bereich der Schmerztherapie von Vorteil sind. Auch der durch einen alternativen Inaktivierungsmechanismus entstehende resurgent current spielt nach Erkenntnissen der jüngsten Zeit eine Rolle im Schmerzgeschehen. Er kann einen Angriffspunkt für neue Analgetika darstellen, so man seine Entstehung und mögliche Modifikationen entschlüsseln kann. Das Ziel dieser Arbeit war es, zu untersuchen, ob ATX-II resurgent currents von Navs in großen und kleinen murinen DRGs verändern bzw. induzieren kann. Zudem sollte beleuchtet werden, ob und wenn ja, welche Wirkung das Toxin auf periphere A- und C Schmerzfasern hat. Die Auswirkungen von ATX-II auf Navs wurden in großen und kleinen DRGs der Maus sowie in Zelllinien mit whole-cell voltage-clamp Messungen untersucht. Gesunde humane Probanden bewerteten Empfindungsänderungen (Schmerz und Juckreiz) nach intrakutaner Injektion von ATX-II. Mit Hilfe des "Laser Doppler Imagers" wurde das mögliche Auftreten eines Axon Reflex Erythems untersucht. Die mittels des FACS Zellsortierers nach Zellgröße sortierten DRGs wurden mit RT-qPCR auf ihren Gehalt an Nav1.6, Nav1.7 und 4 mRNA untersucht. ATX-II verstärkte resurgent currents in großen DRGs, zeigte in kleinen jedoch keinen Effekt. Im heterologen Expressionssystem trat ein resurgent current erst auf, wenn 4 Peptid über die Intrazellulärflüssigkeit zur Verfügung stand. Korrelierend zu den Befunden auf Zellebene rief ATX-II bei intrakutaner Injektion im Menschen nur solange stechenden Schmerz und veränderte mechanische Empfindung hervor, wie die A-Fasern für die Schmerzleitung verfügbar waren. Nachdem ein Nervenkompressionsblock angelegt und die Leitung via A-Fasern blockiert war, waren die ATX-II vermittelten Effekte verschwunden. Zudem konnte kein Axon Reflex Erythem gefunden werden, das ein Zeichen für eine C-Schmerzfaser-Aktivierung wäre. Die Ergebnisse dieser Arbeit legen nahe, dass geringe Konzentrationen von ATX-II eine selektive Wirkung auf große DRGs haben. Erst durch Hinzufügen von 4-Peptid ist es möglich mit dem Toxin resurgent current in kleinen DRGs sowie Zelllinien mit heterolog exprimierten Nav1.6 und Nav1.7 zu induzieren. Dies lässt darauf schließen, dass es kleinen DRGs an 4 in ausreichender Menge mangelt und deshalb kein resurgent current sichtbar ist. Ebenso übt ATX-II einen Effekt auf A Fasern aus, die mit großen DRGs verbunden sind, wohingegen C-Fasern weitgehend unbeeinflusst bleiben. Die intrakutane Injektion von ATX-II führt zu stechendem Schmerz und einer Juckreiz ähnlichen Empfindung, die sich durch A-Faser-Block verhindern lässt. Daraus kann man schließen, dass ATX-II in niedrigen Konzentrationen als spezifischer A-Faser Aktivator fungiert.ATX-II was originally isolated from the venom of the sea anemone Anemonia sulcata and is characterized as a potent voltage-gated sodium channel (Nav) activator, as it induces a persistent sodium current. Recently specific sodium channel subtypes have been linked to human pain. Thus, detailed knowledge of Nav modulation may prove advantageous for the development of new pain treatments. As recently published resurgent current, as a result of an alternative inactivation, also plays a role in pain perception. It could represent a target for new analgesics, if we are able to elicit its origin and possible modifications. The aim of this work was to examine whether ATX-II can induce or change resurgent currents of Navs of large and small murine, sensory dorsal root ganglia neurons (DRGs). It was also to be determined if the toxin has an effect on peripheral A- and C pain fibers. The effects of ATX-II on Navs have been studied in large and small DRGs of mice and in cell lines with whole-cell voltage-clamp measurements. Healthy subjects rated sensation changes (pain and itch) after intracutaneous injection of ATX-II. A Laser Doppler Imager was used for analysis of the occurrence of an axon reflex erythema. Using a FACS sorter DRGs were sorted according to their cell size and were examined by RT-qPCR for their content of 1.6, 1.7 and 4 mRNA. ATX-II increased resurgent currents in large DRGs, but failed to influence small DRGs. In heterologous expression systems, resurgent currents only occurred if the 4-peptide was available intracellularly. ATX-II accordingly produced sharp pain and altered mechanical sensitivity in intracutaneously injected humans only as long as A-fibers were available for the transmission of pain. After a nerve compression block was applied and the A-fibers were blocked, this effect disappeared. In addition, no axon reflex erythema was observed, which would have been a sign for C-fiber activation. The results of this work suggest that low concentrations of ATX-II have a selective effect on large DRGs. Only by adding 4-peptide to the intracellular solution, it is possible to induce resurgent current in small DRGs and cell lines heterologously expressing Nav1.6 and Nav1.7. This suggests that small DRGs lack sufficient amounts of 4 and therefore no resurgent current is detectable. Likewise, ATX-II exerts an effect in large DRG-related A-fibers, whereas C-fibers remain largely unaffected. The intradermal injection of ATX-II causes a sharp pain and itch-like sensation, which can be prevented by selective A-fiber block. This suggests that ATX-II at low concentrations acts as a specific A-fiber activator

Funktionelle Rolle von Smad 2 in der topischen Inflammation, Granulationsgewebeformation und Konsolidierung im Rahmen kutaner Wundheilung

Diverse Studien weisen immer wieder auf die Problematik der sekundären Wundheilung und die sich daraus ergebenden Folgen hin. Ästhetische und funktionelle Einschränkungen sind häufig das Resultat frei granulierender Wunden, bei welchen die Möglichkeit der adaptierten Wundränder nicht gegeben ist. Zytokine spielen eine zentrale Rolle während der Wundheilung, vor allem TGF beta hat großen Einfluss auf die EZM Synthese und letztlich die Wundkontraktion. Sekundäre Wunden weisen hierbei häufig exzessive Kontraktionen auf, welche zu besagten Einschränkungen führen. Inwieweit der Signalweg die Wundheilung beeinflusst, soll in dieser Studie evaluiert werden. Bei 55 Versuchstieren wurden je zwei Exzisionswunden in der Leistenregion gesetzt. Eine Wunde wurde dabei der freien Granulation überlassen (sekundäre Wunde), die Zweite mit drei Einzelknopfnähten verschlossen (primäre Wunde). Nach 3, 7, 14 und 22 Tagen wurden Proben aus dem Wundgebiet entnommen. Entzündliche Infiltration und EZM Synthese wurden histomorphometrisch und die Proteinexpression mittels Westernblot ausgewertet

Amphiphilic nanogels: influence of surface hydrophobicity on protein corona, biocompatibility and cellular uptake

Background and purpose: Nanogels (NGs) are promising drug delivery tools but are typically limited to hydrophilic drugs. Many potential new drugs are hydrophobic. Our study systematically investigates amphiphilic NGs with varying hydrophobicity, but similar colloidal features to ensure comparability. The amphiphilic NGs used in this experiment consist of a hydrophilic polymer network with randomly distributed hydrophobic groups. For the synthesis we used a new synthetic platform approach. Their amphiphilic character allows the encapsulation of hydrophobic drugs. Importantly, the hydrophilic/hydrophobic balance determines drug loading and biological interactions. In particular, protein adsorption to NG surfaces is dependent on hydrophobicity and critically determines circulation time. Our study investigates how network hydrophobicity influences protein binding, biocompatibility and cellular uptake. Methods: Biocompatibility of the NGs was examined by WST-1 assay in monocytic-like THP-1 cells. Serum protein corona formation was investigated using dynamic light scattering and two-dimensional gel electrophoresis. Proteins were identified by liquid chromatography-tandem mass spectrometry. In addition, cellular uptake was analyzed via flow cytometry. Results: All NGs were highly biocompatible. The protein binding patterns for the two most hydrophobic NGs were very similar to each other but clearly different from the hydrophilic ones. Overall, protein binding was increased with increasing hydrophobicity, resulting in increased cellular uptake. Conclusion: Our study supports the establishment of structure–property relationships and contributes to the accurate balance between maximum loading capacity with low protein binding, optimal biological half-life and good biocompatibility. This is an important step to derive design principles of amphiphilic NGs to be applied as drug delivery vehicles

Thermal stability landscape for Klenow DNA polymerase as a function of pH and salt concentration

The thermal denaturation of Klenow DNA polymerase has been characterized over a wide variety of solution conditions to obtain a relative stability landscape for the protein. Measurements were conducted utilizing a miniaturized fluorescence assay that measures Tm based on the increase in the fluorescence of 1,8-anilinonaphthalene sulfonate (ANS) when the protein denatures. The melting temperature (Tm) for Klenow increases as the salt concentration is increased and as the pH is decreased. Klenow\u27s Tm spans a range of over 20 °C, from 40 to 62 °C, depending upon the solution conditions. The landscape reconciles and extends previously measured Tm values for Klenow. Salt effects on the stability of Klenow show strong cation dependence overlaid onto a more typical Hofmeister anion type dependence. Cationic stabilization of proteins has been far less frequently documented than anionic stabilization. The monovalent cations tested stabilize Klenow with the following hierarchy: NH4+ \u3e Na+ \u3e Li+ \u3e K+. Of the divalent cations tested: Mg+2 and Mn+2 significantly stabilize the protein, while Ni+2 dramatically destabilizes the protein. Stability measurements performed in combined Mg+2 plus Na+ salts suggest that the stabilizing effects of these monovalent and divalent cations are synergistic. The cationic stabilization of Klenow can be well explained by a model postulating dampening of repulsion within surface anionic patches on the protein. © 2006 Elsevier B.V. All rights reserved