| 1. |
- Dufil, Gwennael, et al.
(författare)
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Enzyme-assisted in vivo polymerisation of conjugated oligomer based conductors
- 2020
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Ingår i: Journal of materials chemistry. B. - : ROYAL SOC CHEMISTRY. - 2050-750X .- 2050-7518. ; 8:19, s. 4221-4227
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Tidskriftsartikel (refereegranskat)abstract
- Conjugated polymers conduct both electronic and ionic carriers and thus can stimulate and translate biological signals when used as active materials in bioelectronic devices. Self- and on-demand organization of the active material directly in the in vivo environment can result in the seamless integration of the bioelectronic interface. Along that line, we recently demonstrated spontaneous in vivo polymerization of the conjugated oligomer ETE-S in the vascular tissue of plants and the formation of conducting wires. In this work, we elucidate the mechanism of the in vivo polymerization of the ETE-S trimer and demonstrate that ETE-S polymerizes due to an enzymatic reaction where the enzyme peroxidase is the catalyst and hydrogen peroxide is the oxidant. ETE-S, therefore, represents the first example of a conducting polymer that is enzymatically polymerized in vivo. By reproducing the reaction in vitro, we gain further insight on the polymerization mechanism and show that hydrogen peroxide is the limiting factor. In plants the ETE-S triggers the catalytic cycle responsible for the lignification process, hacks this biochemical pathway and integrates within the plant cell wall, forming conductors along the plant structure.
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| 2. |
- Gerasimov, Jennifer, et al.
(författare)
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A Biologically Interfaced Evolvable Organic Pattern Classifier
- 2023
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Ingår i: Advanced Science. - : WILEY. - 2198-3844. ; 10:14
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Tidskriftsartikel (refereegranskat)abstract
- Future brain-computer interfaces will require local and highly individualized signal processing of fully integrated electronic circuits within the nervous system and other living tissue. New devices will need to be developed that can receive data from a sensor array, process these data into meaningful information, and translate that information into a format that can be interpreted by living systems. Here, the first example of interfacing a hardware-based pattern classifier with a biological nerve is reported. The classifier implements the Widrow-Hoff learning algorithm on an array of evolvable organic electrochemical transistors (EOECTs). The EOECTs channel conductance is modulated in situ by electropolymerizing the semiconductor material within the channel, allowing for low voltage operation, high reproducibility, and an improvement in state retention by two orders of magnitude over state-of-the-art OECT devices. The organic classifier is interfaced with a biological nerve using an organic electrochemical spiking neuron to translate the classifiers output to a simulated action potential. The latter is then used to stimulate muscle contraction selectively based on the input pattern, thus paving the way for the development of adaptive neural interfaces for closed-loop therapeutic systems.
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| 3. |
- Gerasimov, Jennifer, et al.
(författare)
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A Biomimetic Evolvable Organic Electrochemical Transistor
- 2021
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 7:11
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Tidskriftsartikel (refereegranskat)abstract
- Biomimicry at the hardware level is expected to overcome at least some of the challenges, including high power consumption, large footprint, two-dimensionality, and limited functionality, which arise as the field of artificial intelligence matures. One of the main attributes that allow biological systems to thrive is the successful interpretation of and response to environmental signals. Taking inspiration from these systems, the first demonstration of using multiple environmental inputs to trigger the formation and control the growth of an evolvable synaptic transistor is reported here. The resulting transistor exhibits long-term changes in the channel conductance at a fixed gate voltage. Biomimetic logic circuits are investigated based on this evolvable transistor that implement temperature and pressure inputs to achieve higher order processes like self-regulation of synaptic strength and coincidence detection.
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| 4. |
- Gerasimov, Jennifer, et al.
(författare)
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An Evolvable Organic Electrochemical Transistor for Neuromorphic Applications
- 2019
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Ingår i: Advanced Science. - : Wiley-VCH Verlagsgesellschaft. - 2198-3844. ; 6:7
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Tidskriftsartikel (refereegranskat)abstract
- An evolvable organic electrochemical transistor (OECT), operating in the hybrid accumulation-depletion mode is reported, which exhibits short-term and long-term memory functionalities. The transistor channel, formed by an electropolymerized conducting polymer, can be formed, modulated, and obliterated in situ and under operation. Enduring changes in channel conductance, analogous to long-term potentiation and depression, are attained by electropolymerization and electrochemical overoxidation of the channel material, respectively. Transient changes in channel conductance, analogous to short-term potentiation and depression, are accomplished by inducing nonequilibrium doping states within the transistor channel. By manipulating the input signal, the strength of the transistor response to a given stimulus can be modulated within a range that spans several orders of magnitude, producing behavior that is directly comparable to short- and long-term neuroplasticity. The evolvable transistor is further incorporated into a simple circuit that mimics classical conditioning. It is forecasted that OECTs that can be physically and electronically modulated under operation will bring about a new paradigm of machine learning based on evolvable organic electronics.
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| 5. |
- Gerasimov, Jennifer Yevgenia, 1985-, et al.
(författare)
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Rational Materials Design for In Operando Electropolymerization of Evolvable Organic Electrochemical Transistors
- 2022
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Ingår i: Advanced Functional Materials. - : John Wiley and Sons Inc. - 1616-301X .- 1616-3028. ; 32
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Tidskriftsartikel (refereegranskat)abstract
- Organic electrochemical transistors formed by in operando electropolymerization of the semiconducting channel are increasingly becoming recognized as a simple and effective implementation of synapses in neuromorphic hardware. However, very few studies have reported the requirements that must be met to ensure that the polymer spreads along the substrate to form a functional conducting channel. The nature of the interface between the substrate and various monomer precursors of conducting polymers through molecular dynamics simulations is investigated, showing that monomer adsorption to the substrate produces an increase in the effective monomer concentration at the surface. By evaluating combinatorial couples of monomers baring various sidechains with differently functionalized substrates, it is shown that the interactions between the substrate and the monomer precursor control the lateral growth of a polymer film along an inert substrate. This effect has implications for fabricating synaptic systems on inexpensive, flexible substrates. © 2022 The Authors.
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| 6. |
- Li, Changbai, et al.
(författare)
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Engineering Conductive Hydrogels with Tissue-like Properties: A 3D Bioprinting and Enzymatic Polymerization Approach
- 2024
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Ingår i: Small Science. - : WILEY. - 2688-4046. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogels are promising materials for medical devices interfacing with neural tissues due to their similar mechanical properties. Traditional hydrogel-based bio-interfaces lack sufficient electrical conductivity, relying on low ionic conductivity, which limits signal transduction distance. Conducting polymer hydrogels offer enhanced ionic and electronic conductivities and biocompatibility but often face challenges in processability and require aggressive polymerization methods. Herein, we demonstrate in situ enzymatic polymerization of π-conjugated monomers in a hyaluronan (HA)-based hydrogel bioink to create cell-compatible, electrically conductive hydrogel structures. These structures were fabricated using 3D bioprinting of HA-based bioinks loaded with conjugated monomers, followed by enzymatic polymerization via horseradish peroxidase. This process increased the hydrogels’ stiffness from about 0.6 to 1.5 kPa and modified their electroactivity. The components and polymerization process were well-tolerated by human primary dermal fibroblasts and PC12 cells. This work presents a novel method to fabricate cytocompatible and conductive hydrogels suitable for bioprinting. These hybrid materials combine tissue-like mechanical properties with mixed ionic and electronic conductivity, providing new ways to use electricity to influence cell behavior in a native-like microenvironment.
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| 7. |
- Padinhare, Harikesh, et al.
(författare)
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Organic electrochemical neurons and synapses with ion mediated spiking
- 2022
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Ingår i: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Future brain-machine interfaces, prosthetics, and intelligent soft robotics will require integrating artificial neuromorphic devices with biological systems. Due to their poor biocompatibility, circuit complexity, low energy efficiency, and operating principles fundamentally different from the ion signal modulation of biology, traditional Silicon-based neuromorphic implementations have limited bio-integration potential. Here, we report the first organic electrochemical neurons (OECNs) with ion-modulated spiking, based on all-printed complementary organic electrochemical transistors. We demonstrate facile bio-integration of OECNs with Venus Flytrap (Dionaea muscipula) to induce lobe closure upon input stimuli. The OECNs can also be integrated with all-printed organic electrochemical synapses (OECSs), exhibiting short-term plasticity with paired-pulse facilitation and long-term plasticity with retention >1000 s, facilitating Hebbian learning. These soft and flexible OECNs operate below 0.6 V and respond to multiple stimuli, defining a new vista for localized artificial neuronal systems possible to integrate with bio-signaling systems of plants, invertebrates, and vertebrates. The integration of artificial neuromorphic devices with biological systems plays a fundamental role for future brain-machine interfaces, prosthetics, and intelligent soft robotics. Harikesh et al. demonstrate all-printed organic electrochemical neurons on Venus flytrap that is controlled to open and close.
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| 8. |
- Priyadarshini, Diana, et al.
(författare)
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Enzymatically Polymerized Organic Conductors on Model Lipid Membranes
- 2023
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Ingår i: Langmuir. - : AMER CHEMICAL SOC. - 0743-7463 .- 1520-5827. ; 39:23, s. 8196-8204
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Tidskriftsartikel (refereegranskat)abstract
- Seamless integration between biological systems and electricalcomponents is essential for enabling a twinned biochemical-electricalrecording and therapy approach to understand and combat neurologicaldisorders. Employing bioelectronic systems made up of conjugated polymers,which have an innate ability to transport both electronic and ioniccharges, provides the possibility of such integration. In particular,translating enzymatically polymerized conductive wires, recently demonstratedin plants and simple organism systems, into mammalian models, is ofparticular interest for the development of next-generation devicesthat can monitor and modulate neural signals. As a first step towardachieving this goal, enzyme-mediated polymerization of two thiophene-basedmonomers is demonstrated on a synthetic lipid bilayer supported ona Au surface. Microgravimetric studies of conducting films polymerizedin situ provide insights into their interactions with a lipid bilayermodel that mimics the cell membrane. Moreover, the resulting electricaland viscoelastic properties of these self-organizing conducting polymerssuggest their potential as materials to form the basis for novel approachesto in vivo neural therapeutics.
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| 9. |
- Sahalianov, Ihor, et al.
(författare)
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Tuning the Emission of Bis-ethylenedioxythiophene-thiophenes upon Aggregation
- 2024
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Ingår i: JOURNAL OF PHYSICAL CHEMISTRY B. - : AMER CHEMICAL SOC. - 1520-6106 .- 1520-5207. ; 128:27, s. 6581-6588
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Tidskriftsartikel (refereegranskat)abstract
- The ability of small lipophilic molecules to penetrate the blood-brain barrier through transmembrane diffusion has enabled researchers to explore new diagnostics and therapies for brain disorders. Until now, therapies targeting the brain have mainly relied on biochemical mechanisms, while electrical treatments such as deep brain stimulation often require invasive procedures. An alternative to implanting deep brain stimulation probes could involve administering small molecule precursors intravenously, capable of crossing the blood-brain barrier, and initiating the formation of conductive polymer networks in the brain through in vivo polymerization. This study examines the aggregation behavior of five water-soluble conducting polymer precursors sharing the same conjugate core but differing in side chains, using spectroscopy and various computational chemistry tools. Our findings highlight the significant impact of side chain composition on both aggregation and spectroscopic response.
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| 10. |
- Strakosas, Xenofon, et al.
(författare)
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Metabolite-induced in vivo fabrication of substrate-free organic bioelectronics
- 2023
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Ingår i: Science. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 379:6634, s. 795-802
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Tidskriftsartikel (refereegranskat)abstract
- Interfacing electronics with neural tissue is crucial for understanding complex biological functions, but conventional bioelectronics consist of rigid electrodes fundamentally incompatible with living systems. The difference between static solid-state electronics and dynamic biological matter makes seamless integration of the two challenging. To address this incompatibility, we developed a method to dynamically create soft substrate-free conducting materials within the biological environment. We demonstrate in vivo electrode formation in zebrafish and leech models, using endogenous metabolites to trigger enzymatic polymerization of organic precursors within an injectable gel, thereby forming conducting polymer gels with long-range conductivity. This approach can be used to target specific biological substructures and is suitable for nerve stimulation, paving the way for fully integrated, in vivo-fabricated electronics within the nervous system.
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