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- Item4D Biofabrication of fibrous artificial nerve graft for neuron regeneration(Bristol : IOP Publ., 2020) Apsite, Indra; Constante, Gissela; Dulle, Martin; Vogt, Lena; Caspari, Anja; Boccaccini, Aldo R.; Synytska, Alla; Salehi, Sahar; Ionov, LeonidIn this paper, we describe the application of the 4D biofabrication approach for the fabrication of artificial nerve graft. Bilayer scaffolds consisting of uniaxially aligned polycaprolactone-poly(glycerol sebacate) (PCL-PGS) and randomly aligned methacrylated hyaluronic acid (HA-MA) fibers were fabricated using electrospinning and further used for the culture of PC-12 neuron cells. Tubular structures form instantly after immersion of fibrous bilayer in an aqueous buffer and the diameter of obtained tubes can be controlled by changing bilayer parameters such as the thickness of each layer, overall bilayer thickness, and medium counterion concentration. Designed scaffolds showed a self-folded scroll-like structure with high stability after four weeks of real-time degradation. The significance of this research is in the fabrication of tuneable tubular nerve guide conduits that can simplify the current existing clinical treatment of neural injuries. © 2020 The Author(s). Published by IOP Publishing Ltd.
- ItemImpacts of enhanced weathering on biomass production for negative emission technologies and soil hydrology(Katlenburg-Lindau [u.a.] : Copernicus, 2020) De Oliveira Garcia, Wagner; Amann, Thorben; Hartmann, Jens; Karstens, Kristine; Popp, Alexander; Boysen, Lena R.; Smith, Pete; Goll, DanielLimiting global mean temperature changes to well below 2 °C likely requires a rapid and large-scale deployment of negative emission technologies (NETs). Assessments so far have shown a high potential of biomass-based terrestrial NETs, but only a few assessments have included effects of the commonly found nutrient-deficient soils on biomass production. Here, we investigate the deployment of enhanced weathering (EW) to supply nutrients to areas of afforestation-reforestation and naturally growing forests (AR) and bioenergy grasses (BG) that are deficient in phosphorus (P), besides the impacts on soil hydrology. Using stoichiometric ratios and biomass estimates from two established vegetation models, we calculated the nutrient demand of AR and BG. Insufficient geogenic P supply limits C storage in biomass. For a mean P demand by AR and a lowgeogenic-P-supply scenario, AR would sequester 119 Gt C in biomass; for a high-geogenic-P-supply and low-AR-Pdemand scenario, 187 Gt C would be sequestered in biomass; and for a low geogenic P supply and high AR P demand, only 92 GtC would be accumulated by biomass. An average amount of ∼ 150 Gt basalt powder applied for EW would be needed to close global P gaps and completely sequester projected amounts of 190 Gt C during the years 2006-2099 for the mean AR P demand scenario (2-362 Gt basalt powder for the low-AR-P-demand and for the high-AR-P-demand scenarios would be necessary, respectively). The average potential of carbon sequestration by EW until 2099 is ∼ 12 GtC (∼ 0:2-∼ 27 Gt C) for the specified scenarios (excluding additional carbon sequestration via alkalinity production). For BG, 8 kg basaltm2 a1 might, on average, replenish the exported potassium (K) and P by harvest. Using pedotransfer functions, we show that the impacts of basalt powder application on soil hydraulic conductivity and plant-Available water, to close predicted P gaps, would depend on basalt and soil texture, but in general the impacts are marginal. We show that EW could potentially close the projected P gaps of an AR scenario and nutrients exported by BG harvest, which would decrease or replace the use of industrial fertilizers. Besides that, EW ameliorates the soil's capacity to retain nutrients and soil pH and replenish soil nutrient pools. Lastly, EW application could improve plant-Available-water capacity depending on deployed amounts of rock powder - adding a new dimension to the coupling of land-based biomass NETs with EW. © 2020 Royal Society of Chemistry. All rights reserved.
- ItemTowards CMOS integrated microfluidics using dielectrophoretic immobilization(Basel : MDPI, 2019) Ettehad, Honeyeh Matbaechi; Yadav, Rahul Kumar; Guha, Subhajit; Wenger, ChristianDielectrophoresis (DEP) is a nondestructive and noninvasive method which is favorable for point-of-care medical diagnostic tests. This technique exhibits prominent relevance in a wide range of medical applications wherein the miniaturized platform for manipulation (immobilization, separation or rotation), and detection of biological particles (cells or molecules) can be conducted. DEP can be performed using advanced planar technologies, such as complementary metal-oxide-semiconductor (CMOS) through interdigitated capacitive biosensors. The dielectrophoretically immobilization of micron and submicron size particles using interdigitated electrode (IDE) arrays is studied by finite element simulations. The CMOS compatible IDEs have been placed into the silicon microfluidic channel. A rigorous study of the DEP force actuation, the IDE’s geometrical structure, and the fluid dynamics are crucial for enabling the complete platform for CMOS integrated microfluidics and detection of micron and submicron-sized particle ranges. The design of the IDEs is performed by robust finite element analyses to avoid time-consuming and costly fabrication processes. To analyze the preliminary microfluidic test vehicle, simulations were first performed with non-biological particles. To produce DEP force, an AC field in the range of 1 to 5 V (peak-to-peak) is applied to the IDE. The impact of the effective external and internal properties, such as actuating DEP frequency and voltage, fluid flow velocity, and IDE’s geometrical parameters are investigated. The IDE based system will be used to immobilize and sense particles simultaneously while flowing through the microfluidic channel. The sensed particles will be detected using the capacitive sensing feature of the biosensor. The sensing and detecting of the particles are not in the scope of this paper and will be described in details elsewhere. However, to provide a complete overview of this system, the working principles of the sensor, the readout detection circuit, and the integration process of the silicon microfluidic channel are briefly discussed. © 2019 by the authors.
- ItemCold atmospheric plasma is a potent tool to improve chemotherapy in melanoma in vitro and in vivo(Basel : MDPI, 2020) Alimohammadi, Mina; Golpour, Monireh; Sohbatzadeh, Farshad; Hadavi, Seyedehniaz; Bekeschus, Sander; Niaki, Haleh Akhavan; Valadan, Reza; Rafiei, AlirezaMalignant melanoma is a devastating disease. Because of its aggressiveness, it also serves as a model tumor for investigating novel therapeutic avenues. In recent years, scientific evidence has shown that cold atmospheric plasma (CAP) might be a promising modality in cancer therapy. In this study, we aimed to evaluate the effect of CAP generated by an argon plasma jet alone or in combination with dacarbazine (DAC) on melanoma cells in vitro and in vivo. The effects of the CAP on inducing lipid peroxidation and nitric oxide production were higher in B16 melanoma cells in comparison to non-malignant L929 cells. Assays on cell growth, apoptosis, and expression of genes related to, e.g., autophagic processes, showed CAP to have a substantial impact in melanoma cells while there were only minoreffects in L929 cells. In vivo, both CAP monotherapy and combination with DAC significantly decreased tumor growth. These results suggest that CAP not only selectively induces cell death in melanoma but also holds promises in combination with chemotherapy that might lead to improved tumor control. © 2020 by the authors.
- ItemOn the liquid chemistry of the reactive nitrogen species peroxynitrite and nitrogen dioxide generated by physical plasmas(Basel : MDPI, 2020) Bruno, Giuliana; Wenske, Sebastian; Lackmann, Jan-Wilm; Lalk, Michael; Von Woedtke, Thomas; Wende, KristianCold physical plasmas modulate cellular redox signaling processes, leading to the evolution of a number of clinical applications in recent years. They are a source of small reactive species, including reactive nitrogen species (RNS). Wound healing is a major application and, as its physiology involves RNS signaling, a correlation between clinical effectiveness and the activity of plasma‐derived RNS seems evident. To investigate the type and reactivity of plasma‐derived RNS in aqueous systems, a model with tyrosine as a tracer was utilized. By high‐resolution mass spectrometry, 26 different tyrosine derivatives including the physiologic nitrotyrosine were identified. The product pattern was distinctive in terms of plasma parameters, especially gas phase composition. By scavenger experiments and isotopic labelling, gaseous nitric dioxide radicals and liquid phase peroxynitrite ions were determined as dominant RNS. The presence of water molecules in the active plasma favored the generation of peroxynitrite. A pilot study, identifying RNS driven post‐translational modifications of proteins in healing human wounds after the treatment with cold plasma (kINPen), demonstrated the presence of in vitro determined chemical pathways. The plasma‐driven nitration and nitrosylation of tyrosine allows the conclusion that covalent modification of biomolecules by RNS contributes to the clinically observed impact of cold plasmas. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- ItemCharacterization of immune cell migration using microfabrication(Berlin ; Heidelberg : Springer, 2021) Vesperini, Doriane; Montalvo, Galia; Qu, Bin; Lautenschläger, FranziskaThe immune system provides our defense against pathogens and aberrant cells, including tumorigenic and infected cells. Motility is one of the fundamental characteristics that enable immune cells to find invading pathogens, control tissue damage, and eliminate primary developing tumors, even in the absence of external treatments. These processes are termed “immune surveillance.” Migration disorders of immune cells are related to autoimmune diseases, chronic inflammation, and tumor evasion. It is therefore essential to characterize immune cell motility in different physiologically and pathologically relevant scenarios to understand the regulatory mechanisms of functionality of immune responses. This review is focused on immune cell migration, to define the underlying mechanisms and the corresponding investigative approaches. We highlight the challenges that immune cells encounter in vivo, and the microfabrication methods to mimic particular aspects of their microenvironment. We discuss the advantages and disadvantages of the proposed tools, and provide information on how to access them. Furthermore, we summarize the directional cues that regulate individual immune cell migration, and discuss the behavior of immune cells in a complex environment composed of multiple directional cues.
- ItemNonenzymatic post-translational modifications in peptides by cold plasma-derived reactive oxygen and nitrogen species(Melville, NY : AIP, 2020) Wenske, Sebastian; Lackmann, Jan-Wilm; Bekeschus, Sander; Weltmann, Klaus-Dieter; Von Woedtke, Thomas; Wende, KristianCold physical plasmas are emerging tools for wound care and cancer control that deliver reactive oxygen species (ROS) and nitrogen species (RNS). Alongside direct effects on cellular signaling processes, covalent modification of biomolecules may contribute to the observed physiological consequences. The potential of ROS/RNS generated by two different plasma sources (kINPen and COST-Jet) to introduce post-translational modifications (PTMs) in the peptides angiotensin and bradykinin was explored. While the peptide backbone was kept intact, a significant introduction of oxidative PTMs was observed. The modifications cluster at aromatic (tyrosine, histidine, and phenylalanine) and neutral amino acids (isoleucine and proline) with the introduction of one, two, or three oxygen atoms, ring cleavages of histidine and tryptophan, and nitration/nitrosylation predominantly observed. Alkaline and acidic amino acid (arginine and aspartic acid) residues showed a high resilience, indicating that local charges and the chemical environment at large modulate the attack of the electron-rich ROS/RNS. Previously published simulations, which include only OH radicals as ROS, do not match the experimental results in full, suggesting the contribution of other short-lived species, i.e., atomic oxygen, singlet oxygen, and peroxynitrite. The observed PTMs are relevant for the biological activity of peptides and proteins, changing polarity, folding, and function. In conclusion, it can be assumed that an introduction of covalent oxidative modifications at the amino acid chain level occurs during a plasma treatment. The introduced changes, in part, mimic naturally occurring patterns that can be interpreted by the cell, and subsequently, these PTMs allow for prolonged secondary effects on cell physiology. © 2020 Author(s).
- ItemA customizable microfluidic platform for medium-throughput modeling of neuromuscular circuits(Amsterdam [u.a.] : Elsevier Science, 2019) Bellmann, Jessica; Goswami, Ruchi Y.; Girardo, Salvatore; Rein, Nelly; Hosseinzadeh, Zohreh; Hicks, Michael R.; Busskamp, Volker; Pyle, April D.; Werner, Carsten; Sterneckert, JaredNeuromuscular circuits (NMCs) are vital for voluntary movement, and effective models of NMCs are needed to understand the pathogenesis of, as well as to identify effective treatments for, multiple diseases, including Duchenne's muscular dystrophy and amyotrophic lateral sclerosis. Microfluidics are ideal for recapitulating the central and peripheral compartments of NMCs, but myotubes often detach before functional NMCs are formed. In addition, microfluidic systems are often limited to a single experimental unit, which significantly limits their application in disease modeling and drug discovery. Here, we developed a microfluidic platform (MFP) containing over 100 experimental units, making it suitable for medium-throughput applications. To overcome detachment, we incorporated a reactive polymer surface allowing customization of the environment to culture different cell types. Using this approach, we identified conditions that enable long-term co-culture of human motor neurons and myotubes differentiated from human induced pluripotent stem cells inside our MFP. Optogenetics demonstrated the formation of functional NMCs. Furthermore, we developed a novel application of the rabies tracing assay to efficiently identify NMCs in our MFP. Therefore, our MFP enables large-scale generation and quantification of functional NMCs for disease modeling and pharmacological drug targeting. © 2019 The Authors
- ItemKaskadennutzung von Lignocellulose : LX-Verfahren trifft auf B. coagulans(Heidelberg : Spektrum, 2020) Schroedter, Linda; Streffer, Friedrich; Streffer, Katrin; Unger, Peter; Venus, JoachimInvestigating alternatives for petrobased substrates, lignocellulose is an interesting yet complex feedstock that offers various possibilities for the design of new and sustainable chemical routes. The novel energy-saving LX-pretreatment was combined with thermophilic Bacillus coagulans. By this, corn straw was used in an innovative cascade obtaining biogas, lignin as well as polymerisable L-(+)-lactic acid of over 99 percents optical purity. © 2020, Die Autoren.
- ItemStarch and Glycogen Analyses : Methods and Techniques(Basel : MDPI, 2020) Brust, Henrike; Orzechowski, Slawomir; Fettke, JoergFor complex carbohydrates, such as glycogen and starch, various analytical methods and techniques exist allowing the detailed characterization of these storage carbohydrates. In this article, we give a brief overview of the most frequently used methods, techniques, and results. Furthermore, we give insights in the isolation, purification, and fragmentation of both starch and glycogen. An overview of the different structural levels of the glucans is given and the corresponding analytical techniques are discussed. Moreover, future perspectives of the analytical needs and the challenges of the currently developing scientific questions are included.