| 1. |
- Bernacka Wojcik, Iwona, et al.
(författare)
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Flexible Organic Electronic Ion Pump for Flow-Free Phytohormone Delivery into Vasculature of Intact Plants
- 2023
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Ingår i: Advanced Science. - : WILEY. - 2198-3844. ; 10:14
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Tidskriftsartikel (refereegranskat)abstract
- Plant vasculature transports molecules that play a crucial role in plant signaling including systemic responses and acclimation to diverse environmental conditions. Targeted controlled delivery of molecules to the vascular tissue can be a biomimetic way to induce long distance responses, providing a new tool for the fundamental studies and engineering of stress-tolerant plants. Here, a flexible organic electronic ion pump, an electrophoretic delivery device, for controlled delivery of phytohormones directly in plant vascular tissue is developed. The c-OEIP is based on polyimide-coated glass capillaries that significantly enhance the mechanical robustness of these microscale devices while being minimally disruptive for the plant. The polyelectrolyte channel is based on low-cost and commercially available precursors that can be photocured with blue light, establishing much cheaper and safer system than the state-of-the-art. To trigger OEIP-induced plant response, the phytohormone abscisic acid (ABA) in the petiole of intact Arabidopsis plants is delivered. ABA is one of the main phytohormones involved in plant stress responses and induces stomata closure under drought conditions to reduce water loss and prevent wilting. The OEIP-mediated ABA delivery triggered fast and long-lasting stomata closure far away from the delivery point demonstrating systemic vascular transport of the delivered ABA, verified delivering deuterium-labeled ABA.
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| 2. |
- Gladisch, Johannes, et al.
(författare)
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An Electroactive Filter with Tunable Porosity Based on Glycolated Polythiophene
- 2022
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Ingår i: Small Science. - : Wiley. - 2688-4046. ; 2:4
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Tidskriftsartikel (refereegranskat)abstract
- The porosity of filters is typically fixed; thus, complex purification processes require application of multiple specialized filters. In contrast, smart filters with controllable and tunable properties enable dynamic separation in a single setup. Herein, an electroactive filter with controllable pore size is demonstrated. The electroactive filter is based on a metal mesh coated with a polythiophene polymer with ethylene glycol sidechains (p(g3T2)) that exhibit unprecedented voltage-driven volume changes. By optimizing the polymer coating on the mesh, controllable porosity during electrochemical addressing is achieved. The pores reversibly open and close, with a dynamic range of more than 95%, corresponding to over 30 mu m change of pores widths. Furthermore, the pores widths could be defined by applied potential with a 10 mu m resolution. From among hundreds of pores from different samples, about 90% of the pores could be closed completely, while only less than 1% are inactive. Finally, the electroactive filter is used to control the flow of a dye, highlighting the potential for flow control and smart filtration applications.
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| 3. |
- Oikonomou, Vasileios, 1992-
(författare)
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Cellulose-based Conducting 3D and 2D Composites for Applications in Plant Science and Responsive Systems
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polymers (Greek: poly=many, meros=part) are large molecules made up of many small parts (monomers) in a repetitive way, as a term was introduced for the first time (1833) by the Swedish chemist, Jöns Jakob Berzelius. By the combination of different monomers, the resulting polymer can exhibit various properties, such as biodegradability, photosensitivity and electrical conductivity. The latter is the main characteristic of the polymers included in this thesis. Since their commercialization, in the late 20th century soft and biocompatible conductive polymers have been substituting stiff and bio-tolerable metals in numerous cases, especially in the medical field for in vivo applications. Polymers can also be found in nature, as a product of the life cycles of animals, plants and microorganisms. The variety of natural polymers is vast, and they are categorized mainly into the groups of polysaccharides, polypeptides and polynucleotides. In these categories belong some of the most well known and investigated materials, for instance, DNA, proteins, silk and cellulose. The combination of synthetic materials with natural materials has intrigued the scientific community for many decades, as a way to form functional materials with hybrid properties. In this thesis, synthetic polymers, particularly conjugated polymers were combined with cellulose, the most abundant biopolymer on earth to form 2D and 3D conducting composites that can find application in plant science and stimuli-responsive systems. In the first part of this thesis, the widely used conjugated polymer PEDOT:PSS was combined with cellulose nanofibers to form 3D porous conducting scaffolds. The scaffolds were developed by freeze-drying method and their electrochemical, mechanical and structural properties were characterized. We investigated the effect of the freezing method on the scaffold properties and found a correlation between the mechanical properties and the pore wall thickness. Furthermore, with micro-CT, we could characterize in detail the bulk structure of the scaffolds and investigate how the incorporation of carbon fibers as addressing electrodes influences the porosity (paper 1). Next, we applied the conducting scaffolds for stimulating plant growth. The plant of our choice was barley, a very important crop, which was grown within the scaffold and the roots were integrated within the scaffold’s pores. We demonstrated that plants grow in the scaffolds under sterile conditions, as well as in agar which is the standard medium used in plant sterile culture. Taking a step ahead, we developed a non-sterile hydroponics setup, where the plants could grow without any contamination. Furthermore, we applied different protocols of electric stimulation to the scaffolds for various time periods and polarizations, achieving at the end a 40% increase in the plant biomass for the stimulated plants. We investigated the growth of the plants and concluded that the enhancement of growth was taking place after the stimulation period with growth enhancement both to roots and shoots (paper 2). In the second part of the thesis, we harnessed the unique electroswelling capabilities of the polythiophene-based polymer p(g3T2), with two different approaches. Initially, we demonstrated the ability of the p(g3T2) material to expand reversibly on a 2D mesh when electrochemically addressed. We optimized the coating on the metallic mesh with fixed pore size and developed an electroactive filter with tunable porosity that could modulate the flow of a system on demand (paper 3). Although p(g3T2) has great potential for various applications, it is processed from hazardous organic solvents, such as chloroform. Therefore, we addressed this issue and developed a protocol where p(g3T2) is solubilized in ethanol, which enables the coating of a plethora of substrates that chloroform would dissolve. From a biodegradable 3D printed mesh of cellulose and polylactide to everyday labware we demonstrated that p(g3T2) can change the substrate properties when electrochemically addressed directly on the non-conducting substrate without the need for an underlying supporting electrode. Forming a biocompatible substrate able to facilitate tissue engineering studies(paper 4). Overall, in this thesis, we demonstrated how synthetic materials can be combined with natural materials to form functional composites with hybrid properties. Firstly, by combining the mechanical characteristics of cellulose and the mixed ionic electronic conductivity of PEDOT:PSS we can obtain a 3D phytocompatible aerogel that can have desired pore size, undergo mechanical compression and act as an active hydroponic substrate for stimulating plant growth. Then we demonstrated how polymers with controllable volume change, such as the polythiophene-based conjugated polymer p(g3T2), can be combined with everyday materials paving the way for stimuli responsive systems such as electroactive filters, and when used with a green solvent can modify everyday labware used for in vitro experiments.
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| 4. |
- Oikonomou, Vasileios, et al.
(författare)
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Elucidating the Bulk Morphology of Cellulose-Based Conducting Aerogels with X-Ray Microtomography
- 2023
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Ingår i: Advanced Materials Technologies. - : WILEY. - 2365-709X. ; 8:23
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Tidskriftsartikel (refereegranskat)abstract
- Conducting cellulose composites are promising sustainable functional materials that have found application in energy devices, sensing and water purification. Herein, conducting aerogels are fabricated based on nanofibrillated cellulose and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, using the ice templating technique, and their bulk morphology is characterized with X-ray microtomography. The freezing method (−20 °C in a freezer vs liquid nitrogen) does not impact the mean porosity of the aerogels but the liquid-N2 aerogels have smaller pores. The integration of carbon fibers as addressing electrodes prior to freezing results in increased mean porosity and pore size in the liquid-N2 aerogels signifying that the carbon fibers alter the morphology of the aerogels when the freezing is fast. Spatially resolved porosity and pore size distributions also reveal that the liquid-N2 aerogels are more inhomogeneous. Independent of the freezing method, the aerogels have similar electrochemical properties. For aerogels without carbon fibers, freezer-aerogels have higher compression modulus and are less stable under cycling compression fatigue test. This can be explained by higher porosity with larger pores in the center of liquid-N2 aerogels and thinner pore walls. This work demonstrates that micro-CT is a powerful tool for characterizing the morphology of aerogels in a non-destructive and spatially resolved manner.
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| 5. |
- Oikonomou, Vasileios, et al.
(författare)
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eSoil : A low-power bioelectronic growth scaffold that enhances crop seedling growth
- 2024
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 121:2
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Tidskriftsartikel (refereegranskat)abstract
- Active hydroponic substrates that stimulate on demand the plant growth have not been demonstrated so far. Here, we developed the eSoil, a low-power bioelectronic growth scaffold that can provide electrical stimulation to the plants' root system and growth environment in hydroponics settings. eSoil's active material is an organic mixed ionic electronic conductor while its main structural component is cellulose, the most abundant biopolymer. We demonstrate that barley seedlings that are widely used for fodder grow within the eSoil with the root system integrated within its porous matrix. Simply by polarizing the eSoil, seedling growth is accelerated resulting in increase of dry weight on average by 50% after 15 d of growth. The effect is evident both on root and shoot development and occurs during the growth period after the stimulation. The stimulated plants reduce and assimilate NO-3more efficiently than controls, a finding that may have implications on minimizing fertilizer use. However, more studies are required to provide a mechanistic understanding of the physical and biological processes involved. eSoil opens the pathway for the development of active hydroponic scaffolds that may increase crop yield in a sustainable manner.
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| 6. |
- Oikonomou, Vasileios, et al.
(författare)
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The Role of Interferon-γ in Autoimmune Polyendocrine Syndrome Type 1.
- 2024
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Ingår i: The New England journal of medicine. - 1533-4406. ; 390:20, s. 1873-1884
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Tidskriftsartikel (refereegranskat)abstract
- Autoimmune polyendocrine syndrome type 1 (APS-1) is a life-threatening, autosomal recessive syndrome caused by autoimmune regulator (AIRE) deficiency. In APS-1, self-reactive T cells escape thymic negative selection, infiltrate organs, and drive autoimmune injury. The effector mechanisms governing T-cell-mediated damage in APS-1 remain poorly understood.We examined whether APS-1 could be classified as a disease mediated by interferon-γ. We first assessed patients with APS-1 who were participating in a prospective natural history study and evaluated mRNA and protein expression in blood and tissues. We then examined the pathogenic role of interferon-γ using Aire-/-Ifng-/- mice and Aire-/- mice treated with the Janus kinase (JAK) inhibitor ruxolitinib. On the basis of our findings, we used ruxolitinib to treat five patients with APS-1 and assessed clinical, immunologic, histologic, transcriptional, and autoantibody responses.Patients with APS-1 had enhanced interferon-γ responses in blood and in all examined autoimmunity-affected tissues. Aire-/- mice had selectively increased interferon-γ production by T cells and enhanced interferon-γ, phosphorylated signal transducer and activator of transcription 1 (pSTAT1), and CXCL9 signals in multiple organs. Ifng ablation or ruxolitinib-induced JAK-STAT blockade in Aire-/- mice normalized interferon-γ responses and averted T-cell infiltration and damage in organs. Ruxolitinib treatment of five patients with APS-1 led to decreased levels of T-cell-derived interferon-γ, normalized interferon-γ and CXCL9 levels, and remission of alopecia, oral candidiasis, nail dystrophy, gastritis, enteritis, arthritis, Sjögren's-like syndrome, urticaria, and thyroiditis. No serious adverse effects from ruxolitinib were identified in these patients.Our findings indicate that APS-1, which is caused by AIRE deficiency, is characterized by excessive, multiorgan interferon-γ-mediated responses. JAK inhibition with ruxolitinib in five patients showed promising results. (Funded by the National Institute of Allergy and Infectious Diseases and others.).
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