| 1. |
- Oikonomou, Vasileios, et al.
(author)
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eSoil : A low-power bioelectronic growth scaffold that enhances crop seedling growth
- 2024
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In: 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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Journal article (peer-reviewed)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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| 2. |
- Abdel Aziz, Ilaria, et al.
(author)
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Drug delivery via a 3D electro-swellable conjugated polymer hydrogel
- 2024
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In: Journal of materials chemistry. B. - : ROYAL SOC CHEMISTRY. - 2050-750X .- 2050-7518.
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Journal article (peer-reviewed)abstract
- Spatiotemporal controlled drug delivery minimizes side-effects and enables therapies that require specific dosing patterns. Conjugated polymers (CP) can be used for electrically controlled drug delivery; however so far, most demonstrations were limited to molecules up to 500 Da. Larger molecules could be incorporated only during the CP polymerization and thus limited to a single delivery. This work harnesses the record volume changes of a glycolated polythiophene p(g3T2) for controlled drug delivery. p(g3T2) undergoes reversible volumetric changes of up to 300% during electrochemical doping, forming pores in the nm-size range, resulting in a conducting hydrogel. p(g3T2)-coated 3D carbon sponges enable controlled loading and release of molecules spanning molecular weights of 800-6000 Da, from simple dyes up to the hormone insulin. Molecules are loaded as a combination of electrostatic interactions with the charged polymer backbone and physical entrapment in the porous matrix. Smaller molecules leak out of the polymer while larger ones could not be loaded effectively. Finally, this work shows the temporally patterned release of molecules with molecular weight of 1300 Da and multiple reloading and release cycles without affecting the on/off ratio.
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| 3. |
- Abdel Aziz, Ilaria, et al.
(author)
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Electrochemical modulation of mechanical properties of glycolated polythiophenes
- 2024
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In: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355.
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Journal article (peer-reviewed)abstract
- Electrochemical doping of organic mixed ionic-electronic conductors is key for modulating their conductivity, charge storage and volume enabling high performing bioelectronic devices such as recording and stimulating electrodes, transistors-based sensors and actuators. However, electrochemical doping has not been explored to the same extent for modulating the mechanical properties of OMIECs on demand. Here, we report a qualitative and quantitative study on how the mechanical properties of a glycolated polythiophene, p(g3T2), change in situ during electrochemical doping and de-doping. The Young's modulus of p(g3T2) changes from 69 MPa in the dry state to less than 10 MPa in the hydrated state and then further decreases down to 0.4 MPa when electrochemically doped. With electrochemical doping-dedoping the Young's modulus of p(g3T2) changes by more than one order of magnitude reversibly, representing the largest modulation reported for an OMIEC. Furthermore, we show that the electrolyte concentration affects the magnitude of the change, demonstrating that in less concentrated electrolytes more water is driven into the film due to osmosis and therefore the film becomes softer. Finally, we find that the oligo ethylene glycol side chain functionality, specifically the length and asymmetry, affects the extent of modulation. Our findings show that glycolated polythiophenes are promising materials for mechanical actuators with a tunable modulus similar to the range of biological tissues, thus opening a pathway for new mechanostimulation devices. This work investigates the changes in the mechanical properties of glycolated polythiophenes induced by electrochemical addressing and by electrolyte concentration, due to its ability to stabilize water.
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| 4. |
- Cowan-Turner, Daniel, et al.
(author)
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Sequencing complex plants on a budget: The development of Kalanchoë blossfeldiana as a C3, CAM comparative tool
- 2024
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In: Plants, People, Planet. - : WILEY. - 2572-2611.
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Journal article (peer-reviewed)abstract
- Despite the increasing number of well-studied plant species with well-annotated genomes across plant life, there are few densely sampled genera with more than a couple of genome sequences representing the diversity of whole genera. Here, we develop an economic approach to full-genome sequencing that could be used to sequence many species within a genus. We made use of the Nanopore rapid sequencing kit to assist in plant genome assembly, dramatically reducing the cost. Here we applied this method to cost-effectively develop genomic resources for Kalancho & euml; blossfeldiana, a commercially important ornamental, in which Crassulacean Acid Metabolism (CAM), a water-conserving mode of photosynthesis can be induced. We present a physiological and biochemical characterisation of Kalanchoe blossfeldiana with its nuclear and chloroplastic genome and a comparative C3, CAM dusk transcriptome. We apply this approach to a complex tetraploid genome, making use of a relative species for chromosomal scaffolding to reduce assembly ploidy, we provide a resource for future gene expression studies. We highlight its limitations, e.g. the need for deeper sequencing to accurately resolve genome structure and haplotypes without using a relative species for scaffolding. T he study demonstrates the merits of K. blossfeldiana as a comparative system for studying C3 and CAM within a plant and has identified substantial changes in the dusk transcriptome between young C3 and mature CAM K. blossfeldiana leaves in response to age-induced CAM, and shows that in the absence of abiotic stress, CAM induction still involves the engagement of drought and abscisic acid (ABA) response pathways.
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| 5. |
- Parker, Daniela, et al.
(author)
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Biohybrid Energy Storage Circuits Based on Electronically Functionalized Plant Roots
- 2024
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In: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252.
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Research review (peer-reviewed)abstract
- Biohybrid systems based on plants integrate plant structures and processes into technological components targeting more sustainable solutions. Plants' biocatalytic machinery, for example, has been leveraged for the organization of electronic materials directly in the vasculature and roots of living plants, resulting in biohybrid electrochemical devices. Among other applications, energy storage devices were demonstrated where the charge storage electrodes were seamlessly integrated into the plant tissue. However, the capacitance and the voltage output of a single biohybrid supercapacitor are limited. Here, we developed biohybrid circuits based on functionalized conducting roots, extending the performance of plant based biohybrid energy storage systems. We show that root-supercapacitors can be combined in series and in parallel configuration, achieving up to 1.5 V voltage output or up to 11 mF capacitance, respectively. We further demonstrate that the supercapacitors circuit can be charged with an organic photovoltaic cell, and that the stored charge can be used to power an electrochromic display or a bioelectronic device. Furthermore, the functionalized roots degrade in composting similarly to native roots. The proof-of-concept demonstrations illustrate the potential of this technology to achieve more sustainable solutions for powering low consumption devices such as bioelectronics for agriculture or IoT applications.
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| 6. |
- Routier, Cyril, 1996-
(author)
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Plant Nanobionics : From Localized Carbon Capture to Precision Molecular Delivery
- 2024
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Doctoral thesis (other academic/artistic)abstract
- Photosynthesis is an evolutionary marvel that not only sustains plant life but also profoundly shaped the climatic conditions necessary for the development of other advanced forms of life and the ecosystems we know today. During photosynthesis, plants harness the energy of light to convert carbon dioxide (CO2), one of the main greenhouse gases, into sugars for the growth of both themselves and organisms that consume plants, and oxygen that sustains life on Earth. As we face the challenges of a rapidly changing climate and growing global population, understanding and enhancing the functions of plants such as photosynthesis and drought tolerance is of major importance.With advances in materials science over the years, an increasing number of nanotechnologies harnessing the unique properties of materials with sizes in the nanometer range (<100 nm) are emerging, holding promise to revolutionize various sectors, including agriculture and plant biology. At the intersection of materials science and plant biology, the field of plant nanobionics emerges as a transformative discipline pioneering a novel approach to integrating nanomaterials directly into plant systems. Departing from traditional genetic modification, this interdisciplinary field seeks to create bio-hybrid systems to enhance plants’ natural functions such as photosynthesis or introduce entirely new capabilities such as environmental sensing, monitoring, or even light emission.Various strategies exist in plant nanobionics, including the use of carbon nanotubes, silica nanoparticles, liposomes, or even quantum dots. The use of polymers, which consist of long chains of molecules with repeating units, has also been particularly intriguing for nanotechnological and nanobionic approaches due to their versatile and tunable properties.The primary focus of this thesis was to increase the diffusion rate of atmospheric CO2 in the leaves of tobacco plants using polymeric nanoparticles. The nanoparticles are engineered to directly capture CO2 from the atmosphere and are able to cross various plant cell membranes to deliver it to the photosynthetic reaction centers. The initial carboxylation reaction of photosynthesis, where atmospheric CO2 is converted into sugar precursors (3-phosphoglyceric acid or 3-PGA) with the help of the enzyme RuBisCO, is often considered the limiting step of the photosynthetic process. The poor affinity of RuBisCO to CO2 coupled with the limited diffusion of CO2 to the reaction sites is responsible for a considerable reduction in the potential photosynthetic efficiency of plants.With that in mind, we designed nanoparticles based on polyethyleneimine, a polymer able to capture atmospheric CO2 and cross cellular membranes, and modified it with chitosan, a biocompatible polymer, to design nanoparticles that we further labeled with fluorescein isothiocyanate (FITC) for fluorescent observation purposes. We studied their ability to self-integrate into plant cells and the plant chloroplasts, where the photosynthetic reaction occurs, without causing harm to the cells or the plants in general. We further evaluated the capacity of the nanoparticles to integrate into plant cells in culture and demonstrated that the nanoparticles have a natural affinity for the cells and self-integrate in the cells, crossing the cell wall, after 3 days. The nanoparticles also had no negative impact on the capacity of the cells to keep growing and dividing. We also demonstrated the nanoparticles' ability to still capture atmospheric CO2 when integrated into plant leaves and, in vitro, to redistribute it to RuBisCO enhancing the production of 3-PGA by 20%. Since the entry of the nanoparticles into plant leaves requires forced infiltration using a syringe infiltration method, we also studied the impact of the method itself on the plants' natural capacity to uptake CO2 and perform photosynthesis. We found there was a temporary impact of the infiltration process on the leaves’ natural CO2 uptake that also resulted in a reduction of their natural photosynthetic abilities. This will enable future studies to reliably quantify the impact of the nanoparticles on plant processes. We also used an organic electronic ion pump as a precision delivery method to study the impact of various biomolecules, such as malic and abscisic acid, on the plants' natural regulation of carbon dioxide uptake through the leaf pores known as stomata.Our work elucidates the various mechanisms at play when infiltrating nanoparticles or delivering biomolecules into plant leaves and plant cells in culture. We demonstrated a proof-of-concept use of phytocompatible nanoparticles in vivo, paving the way for a nanomaterials-based CO2-concentrating mechanism in plants that can potentially increase plants’ photosynthetic efficiency and overall CO2 storage.
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