Isotropic contact patterning to improve reproducibility in organic thin-film transistors

A novel approach for improving reproducibility of Organic Field-Effect Transistors electrical performances is proposed. The introduction of isotropic features in the layout of source and drain electrodes is employed to minimize the impact of randomly-distributed crystalline domains in the organic semiconductor film on the reproducibility of basic electrical parameters, such as threshold voltage and charge carrier mobility. A significant reduction of the standard deviation of these parameters is reported over a statistically-relevant set of devices with drop-casted semiconductor, if compared with results obtained in a standard, interdigitated transistor structure. A correlation between electrodes patterning and proposed result is demonstrated by deepening the analysis with the contribution of meniscus-assisted semiconductor printing, in order to precisely control the growth direction of crystals

Optimization of organic field-effect transistor-based mechanical sensors to anisotropic and isotropic deformation detection for wearable and e-skin applications

Flexible electronics represent a viable technology for the development of innovative mechanical sensors. This paper reports a detailed study of electro-mechanical performances of Organic Field-Effect Transistor-based sensor, investigating the role of source-drain electrodes layout in combination with organic semiconductor morphology obtained by different patterning methods. Two different sensor structures, with interdigitated and spiral-shaped source and drain electrodes, are employed together with solution-processed organic semiconductors deposited by drop-casting or patterned by means of meniscus-guided printing. This technique allows the orientation of crystalline domains to specific directions, and was employed to provide anisotropic or isotropic semiconductor patterns onto the transistor’s channel area. The different device configurations are tested as strain gauges and tactile sensors, by imposing anisotropic surface strain or complex deformations by means of custom-made, 3D-printed indenters. A wise choice of device structure and semiconductor patterning allows optimizing sensing performances as a response to specific deformations: interdigitated devices with crystalline domains aligned along the channel length direction are ideal strain gauges, while sensors with spiral-shaped electrodes in combination with isotropic semiconductor patterning are preferential for reproducing the sense of touch, which deals with the transduction of more complex deformation patterns. These results pave the way to the development of innovative sensors in the field of flexible bioengineering, in particular for the development of wearable and e-skin applications for joint motion monitoring and tactile sensing

Regioselective O-glucuronidation of deoxynivalenol

Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersDeoxynivalenol (DON) ist ein Mycotoxin (Pilzgift), das von verschiedenen Gattungen der Fusarienfamilie gebildet wird. Aufgrund der Stabilität des Toxins und dessen Teratogenität ist das Interesse an diesem Mycotoxin in den letzten Jahren erheblich gestiegen. Vor allem im Bereich der Agrarbiotechnologie wird versucht, durch neue Technologien die verursachten Schäden zu verringern. DON ist mittlerweile gut untersucht, und Grenzwerte sowie Messmethoden für dessen Nachweis vorhanden. Allerdings können auch die beim Stoffwechsel entstehenden Konjugate mit Glucuronsäure (zur Steigerung der Wasserlöslichkeit) eine Wirkung auf den Wirtsorganismus haben. Darüber hinaus können die gebildeten Glycokonjugate ausgeschieden und an der Oberfläche angereichert werden, wobei diese nicht durch herkömmliche Tests erfasst werden. Aus diesem Grund ist es von großem Interesse, diese Substanzen quantifizieren und deren Wirkung abschätzen zu können.Das hauptsächliche Ziel der vorliegenden Arbeit ist die Synthese der beiden in der Natur auftretenden Glucuronide von DON, DON-3-beta-D-glucuronid bzw. DON-15-beta-D-glucuronid. Anders als eine enzymatische Reaktion, die im Rahmen des Stoffwechsels auftritt, stellt eine synthetische Glucuronidierungsreaktion eine wesentlich schwierigere Aufgabe dar, da es abhängig von der Art des Zielmoleküls eine Vielzahl an verschiedenen Reaktionsmöglichkeiten gibt. Da DON kaum verfügbar ist und dessen Anschaffung üblicherweise mit immensen Kosten verbunden ist, war es notwendig die Methoden an geeigneten Modellverbindungen zu testen. Dazu wurde eine Reihe von einfachen Modellen synthetisiert und verschiedenen Glucuronidierungsmethoden unterzogen. Die dabei gewonnen Erkenntnisse wurden anschließen bei der Gucuronidierung von DON eingesetzt, wobei beide geschützten Glucuronide in guten Ausbeuten erhalten wurden. Eine Isolierung von DON-15-glucuronid gelang nach der Abspaltung der Schutzgruppen aufgrund einer Weiterreaktion des Endproduktes nicht, jedoch konnte DON-3-beta-D-glucuronid stereoselektiv und in zufriedenstellenden Ausbeuten isoliert werden.9

Stereoselective Luche Reduction of Deoxynivalenol and Three of Its Acetylated Derivatives at C8

The trichothecene mycotoxin deoxynivalenol (DON) is a well known and common contaminant in food and feed. Acetylated derivatives and other biosynthetic precursors can occur together with the main toxin. A key biosynthetic step towards DON involves an oxidation of the 8-OH group of 7,8-dihydroxycalonectrin. Since analytical standards for the intermediates are not available and these intermediates are therefore rarely studied, we aimed for a synthetic method to invert this reaction, making a series of calonectrin-derived precursors accessible. We did this by developing an efficient protocol for stereoselective Luche reduction at C8. This method was used to access 3,7,8,15-tetrahydroxyscirpene, 3-deacetyl-7,8-dihydroxycalonectrin, 15-deacetyl-7,8-dihydroxycalonectrin and 7,8-dihydroxycalonectrin, which were characterized using several NMR techniques. Beside the development of a method which could basically be used for all type B trichothecenes, we opened a synthetic route towards different acetylated calonectrins

Pentahydroxyscirpene—Producing Strains, Formation In Planta, and Natural Occurrence

Trichothecenes are a class of structurally diverse mycotoxins with more than 200 naturally occurring compounds. Previously, a new compound, pentahydroxyscirpene (PHS), was reported as a byproduct of a nivalenol producing Fusarium strain, IFA189. PHS contains a hydroxy group at C-8 instead of the keto group of type B trichothecenes. In this work, we demonstrate that IFA189 belongs to the species Fusarium kyushuense using molecular tools. Production of PHS in vitro was also observed for several isolates of other Fusarium species producing nivalenol. Furthermore, we report the formation of 4-acetyl-PHS by F. kyushuense on inoculated rice. Wheat ears of the variety Remus were infected with IFA189 and the in planta production of PHS was confirmed. Natural occurrence of PHS was verified in barley samples from the Czech Republic using a liquid chromatographic-tandem mass spectrometric method validated for this purpose. Toxicity of PHS to wheat ribosomes was evaluated with a coupled in vitro transcription and translation assay, which showed that PHS inhibits protein biosynthesis slightly less than nivalenol and deoxynivalenol

Metabolism of Deoxynivalenol and Deepoxy-Deoxynivalenol in Broiler Chickens, Pullets, Roosters and Turkeys

Recently, deoxynivalenol-3-sulfate (DON-3-sulfate) was proposed as a major DON metabolite in poultry. In the present work, the first LC-MS/MS based method for determination of DON-3-sulfate, deepoxy-DON-3-sulfate (DOM-3-sulfate), DON, DOM, DON sulfonates 1, 2, 3, and DOM sulfonate 2 in excreta samples of chickens and turkeys was developed and validated. To this end, DOM-3-sulfate was chemically synthesized and characterized by NMR and LC-HR-MS/MS measurements. Application of the method to excreta and chyme samples of four feeding trials with turkeys, chickens, pullets, and roosters confirmed DON-3-sulfate as the major DON metabolite in all poultry species studied. Analogously to DON-3-sulfate, DOM-3-sulfate was formed after oral administration of DOM both in turkeys and in chickens. In addition, pullets and roosters metabolized DON into DOM-3-sulfate. In vitro transcription/translation assays revealed DOM-3-sulfate to be 2000 times less toxic on the ribosome than DON. Biological recoveries of DON and DOM orally administered to broiler chickens, turkeys, and pullets were 74%–106% (chickens), 51%–72% (roosters), and 131%–151% (pullets). In pullets, DON-3-sulfate concentrations increased from jejunum chyme samples to excreta samples by a factor of 60. This result, put into context with earlier studies, indicates fast and efficient absorption of DON between crop and jejunum, conversion to DON-3-sulfate in intestinal mucosa, liver, and possibly kidney, and rapid elimination into excreta via bile and urine

Immunoassay and amperometric biosensor approaches for the detection of deltamethrin in seawater

The study of an enzyme-linked immunosorbent assay (ELISA) and an amperometric biosensor for the detection of the pyrethroid deltamethrin in seawater is reported. The preparation of specific polyclonal antibodies is addressed using two immunizing haptens based on deltamethrin and cypermethrin compounds, with a spacer arm placed at the cyano residue in the pyrethroid structure. Different conjugates based on bovine serum albumin and aminodextran are prepared depending on the lipophilic profile of the competitor haptens studied. A reproducible and sensitive indirect competitive ELISA is developed, reaching a limit of detection of 1.2 ± 0.04 μg L−1 and an IC50 value of 21.4 ± 0.3 μg L−1 (both n = 3). For validation of the assays described, artificial seawater samples fortified with deltamethrin are analyzed. For the ELISA assay, these accuracy studies reported a slope of 0.904. An amperometric immunosensor is developed using the same immunoreagents and achieving a comparable detectability in terms of LOD of 4.7 μg L−1, measuring seawater without any pretreatment. These results suggest that both techniques can be used as rapid and simple analytical methods for deltamethrin quantification in seawater samples, which are great candidates for initial environmental screening programs. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.Funding information This work has been funded by SEA-on-a-CHIP project (FP7-OCEAN-2013, no 614168). The Nb4D group (formerly Applied Molecular Receptors group, AMRg) is a consolidated research group (Grup de Recerca) of the Generalitat de Catalunya and has support from the Departament d’Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya (expedient: 2014 SGR 1484). CIBER-BBN is an initiative funded by the Spanish National Plan for Scientific and Technical Research and Innovation 2013–2016; Iniciativa Ingenio 2010, Consolider Program, and CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. The ICTS BNANOBIOSIS,^ and particularly the Custom Antibody Service (CAbS, IQAC-CSIC, CIBER-BBN), is acknowledged for the assistance and support related to the immunoreagents used in this work.Peer reviewe

The Metabolic Fate of Deoxynivalenol and Its Acetylated Derivatives in a Wheat Suspension Culture: Identification and Detection of DON-15-O-Glucoside, 15-Acetyl-DON-3-O-Glucoside and 15-Acetyl-DON-3-Sulfate

Deoxynivalenol (DON) is a protein synthesis inhibitor produced by the Fusarium species, which frequently contaminates grains used for human or animal consumption. We treated a wheat suspension culture with DON or one of its acetylated derivatives, 3-acetyl-DON (3-ADON), 15-acetyl-DON (15-ADON) and 3,15-diacetyl-DON (3,15-diADON), and monitored the metabolization over a course of 96 h. Supernatant and cell extract samples were analyzed using a tailored LC-MS/MS method for the quantification of DON metabolites. We report the formation of tentatively identified DON-15-O-β-D-glucoside (D15G) and of 15-acetyl-DON-3-sulfate (15-ADON3S) as novel deoxynivalenol metabolites in wheat. Furthermore, we found that the recently identified 15-acetyl-DON-3-O-β-D-glucoside (15-ADON3G) is the major metabolite produced after 15-ADON challenge. 3-ADON treatment led to a higher intracellular content of toxic metabolites after six hours compared to all other treatments. 3-ADON was exclusively metabolized into DON before phase II reactions occurred. In contrast, we found that 15-ADON was directly converted into 15-ADON3G and 15-ADON3S in addition to metabolization into deoxynivalenol-3-O-β-D-glucoside (D3G). This study highlights significant differences in the metabolization of DON and its acetylated derivatives