| 1. |
- Armada Moreira, Adam, et al.
(författare)
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Benchmarking organic electrochemical transistors for plant electrophysiology
- 2022
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Plants are able to sense and respond to a myriad of external stimuli, using different signal transduction pathways, including electrical signaling. The ability to monitor plant responses is essential not only for fundamental plant science, but also to gain knowledge on how to interface plants with technology. Still, the field of plant electrophysiology remains rather unexplored when compared to its animal counterpart. Indeed, most studies continue to rely on invasive techniques or on bulky inorganic electrodes that oftentimes are not ideal for stable integration with plant tissues. On the other hand, few studies have proposed novel approaches to monitor plant signals, based on non-invasive conformable electrodes or even organic transistors. Organic electrochemical transistors (OECTs) are particularly promising for electrophysiology as they are inherently amplification devices, they operate at low voltages, can be miniaturized, and be fabricated in flexible and conformable substrates. Thus, in this study, we characterize OECTs as viable tools to measure plant electrical signals, comparing them to the performance of the current standard, Ag/AgCl electrodes. For that, we focused on two widely studied plant signals: the Venus flytrap (VFT) action potentials elicited by mechanical stimulation of its sensitive trigger hairs, and the wound response of Arabidopsis thaliana. We found that OECTs are able to record these signals without distortion and with the same resolution as Ag/AgCl electrodes and that they offer a major advantage in terms of signal noise, which allow them to be used in field conditions. This work establishes these organic bioelectronic devices as non-invasive tools to monitor plant signaling that can provide insight into plant processes in their natural environment.
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| 2. |
- Berto, Marcello, et al.
(författare)
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EGOFET Peptide Aptasensor for Label-Free Detection of Inflammatory Cytokines in Complex Fluids
- 2018
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Ingår i: ADVANCED BIOSYSTEMS. - : WILEY-V C H VERLAG GMBH. - 2366-7478. ; 2:2
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Tidskriftsartikel (refereegranskat)abstract
- Organic electronic transistors are rapidly emerging as ultrahigh sensitive label-free biosensors suited for point-of-care or in-field deployed applications. Most organic biosensors reported to date are based on immunorecognition between the relevant biomarkers and the immobilized antibodies, whose use is hindered by large dimensions, poor control of sequence, and relative instability. Here, an electrolyte-gated organic field effect transistor (EGOFET) biosensor where the recognition units are surface immobilized peptide aptamers (Affimer proteins) instead of antibodies is reported. Peptide aptasensor for the detection of the pro-inflammatory cytokine tumor necrosis factor alpha (TNF alpha) with a 1 x 10(-12) M limit of detection is demonstrated. Ultralow sensitivity is met even in complex solutions such as cell culture media containing 10% serum, demonstrating the remarkable ligand specificity of the device. The device performances, together with the simple one-step immobilization strategy of the recognition moieties and the low operational voltages, all prompt EGOFET peptide aptasensors as candidates for early diagnostics and monitoring at the point-of-care.
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| 3. |
- Berto, Marcello, et al.
(författare)
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Label free urea biosensor based on organic electrochemical transistors
- 2018
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Ingår i: Flexible and Printed Electronics. - : IOP Publishing. - 2058-8585. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- The quantification of urea is of the utmost importance not only in medical diagnosis, where it serves as a potential indicator of kidney and liver disfunction, but also in food safety and environmental control. Here, we describe a urea biosensor based on urease entrapped in a crosslinked gelatin hydrogel, deposited onto a fully printed PEDOT:PSS-based organic electrochemical transistor (OECT). The device response is based on the modulation of the channel conductivity by the ionic species produced upon urea hydrolysis catalyzed by the entrapped urease. The biosensor shows excellent reproducibility, a limit of detection as low as 1 μM and a response time of a few minutes. The fabrication of the OECTs by screen-printing on flexible substrates ensures a significant reduction in manufacturing time and costs. The low dimensionality and operational voltages (0.5 V or below) of these devices contribute to make these enzymatic OECT-based biosensors as appealing candidates for high-throughput monitoring of urea levels at the point-of-care or in the field.
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| 4. |
- Burtscher, Bernhard, et al.
(författare)
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Sensing Inflammation Biomarkers with Electrolyte-Gated Organic Electronic Transistors
- 2021
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Ingår i: Advanced Healthcare Materials. - : Wiley. - 2192-2640 .- 2192-2659. ; 10:20
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Forskningsöversikt (refereegranskat)abstract
- An overview of cytokine biosensing is provided, with a focus on the opportunities provided by organic electronic platforms for monitoring these inflammation biomarkers which manifest at ultralow concentration levels in physiopathological conditions. Specifically, two of the fields state-of-the-art technologies-organic electrochemical transistors (OECTs) and electrolyte gated organic field effect transistors (EGOFETs)-and their use in sensing cytokines and other proteins associated with inflammation are a particular focus. The overview will include an introduction to current clinical and "gold standard" quantification techniques and their limitations in terms of cost, time, and required infrastructure. A critical review of recent progress with OECT- and EGOFET-based protein biosensors is presented, alongside a discussion onthe future of these technologies in the years and decades ahead. This is especially timely as the world grapples with limited healthcare diagnostics during the Coronavirus disease (COVID-19)pandemic where one of the worst-case scenarios for patients is the "cytokine storm." Clearly, low-cost point-of-care technologies provided by OECTs and EGOFETs can ease the global burden on healthcare systems and support professionals by providing unprecedented wealth of data that can help to monitor disease progression in real time.
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| 5. |
- Diacci, Chiara, et al.
(författare)
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Diurnal in vivo xylem sap glucose and sucrose monitoring using implantable organic electrochemical transistor sensors
- 2021
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Ingår i: iScience. - : Cell Press. - 2589-0042. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Bioelectronic devices that convert biochemical signals to electronic readout enable biosensing with high spatiotemporal resolution. These technologies have been primarily applied in biomedicine while in plants sensing is mainly based on invasive methods that require tissue sampling, hindering in-vivo detection and having poor spatiotemporal resolution. Here, we developed enzymatic biosensors based on organic electrochemical transistors (OECTs) for in-vivo and real-time monitoring of sugar fluctuations in the vascular tissue of trees. The glucose and sucrose OECT-biosensors were implanted into the vascular tissue of trees and were operated through a low-cost portable unit for 48hr. Our work consists a proof-of-concept study where implantable OECT-biosensors not only allow real-time monitoring of metabolites in plants but also reveal new insights into diurnal sugar homeostasis. We anticipate that this work will contribute to establishing bioelectronic technologies as powerful minimally invasive tools in plant science, agriculture and forestry.
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| 6. |
- Diacci, Chiara, et al.
(författare)
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Label-free detection of interleukin-6 using electrolyte gated organic field effect transistors
- 2017
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Ingår i: Biointerphases. - : AMER INST PHYSICS. - 1934-8630 .- 1559-4106. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- Cytokines are small proteins that play fundamental roles in inflammatory processes in the human body. In particular, interleukin (IL)-6 is a multifunctional cytokine, whose increased levels are associated with infection, cancer, and inflammation. The quantification of IL-6 is therefore of primary importance in early stages of inflammation and in chronic diseases, but standard techniques are expensive, time-consuming, and usually rely on fluorescent or radioactive labels. Organic electronic devices and, in particular, organic field-effect transistors (OFETs) have been proposed in the recent years as novel platforms for label-free protein detection, exploiting as sensing unit surface-immobilized antibodies or aptamers. Here, the authors report two electrolyte-gated OFETs biosensors for IL-6 detection, featuring monoclonal antibodies and peptide aptamers adsorbed at the gate. Both strategies yield biosensors that can work on a wide range of IL-6 concentrations and exhibit a remarkable limit of detection of 1 pM. Eventually, electrolyte gated OFETs responses have been used to extract and compare the binding thermodynamics between the sensing moiety, immobilized at the gate electrode, and IL-6. (C) 2017 American Vacuum Society.
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| 7. |
- Diacci, Chiara, 1992-
(författare)
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Organic Bioelectronic Devices for Selective Biomarker Sensing : Towards Integration with Living Systems
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Inorganic materials have been the main players of the semiconductor industry for the past forty years. However, there has been a continuous interest and growth in the research and in the application of organic semiconductors (OSCs) as active materials in electronic devices, due to the possibility to process these materials at low temperature on flexible substrates, fabricate them on large-area, and upscale their fabrication using cost-effective strategies such as printing. Because of these features, organic electronic devices are rapidly emerging as biosensors for biomarkers, with a high potential for becoming a high-throughput tool even deployable at the point-of-care. One of the most used and studied platforms is the organic electrochemical transistor (OECT). OECTs have been largely used as biosensors in order to transduce and amplify electrical signals or detect biological analytes upon proper functionalization with specific biorecognition units. OECTs can operate at low voltages, are easy to fabricate on different substrates, and are compatible with the aqueous environment, and can therefore be interfaced with living systems, ranging from mammals to plants. The OECT device configuration includes a gate electrode that modulates the current in the channel through an electrolyte, which can be not only a buffered solution but even a complex biological fluid. When OECTs are operated as biosensors, the sensing mechanism relies on the current variation generated from specific reactions with the analyte of interest. These devices are paving the way to the development of point-of-care technologies and portable biosensors with fast and label-free detection. Moreover, OECTs can help to reveal new biological insight and allow a better understanding of physiological processes. During my PhD, I focused on design, fabrication, and validation of different OECT-based biosensors for the detection of biomarkers that are relevant for healthcare applications, thus showing their high potential as a proper sensing platform. We developed sensors towards different analytes, ranging from small molecules to proteins, with ad hoc designed materials strategies to endow the device with selectivity towards the species of interest. Most notably, I also demonstrated the possibility of integrating OECTs in plants, as an example of interfacing these biosensors with living systems. In the first two papers, we developed screen printed OECTs, presenting PEDOT:PSS as the semiconducting material on the channel. In the first case, the device also featured a PEDOT:PSS gate electrode which was further functionalized with biocompatible gelatin and the enzyme urease to ensure selectivity toward the analyte of interest, namely urea. The biosensor was able to monitor increasing urea concentrations with a limit of detection of 1 µM. In the second paper the screen-printed carbon gate electrode was first modified with platinum and then we ensured selectivity towards the analyte uric acid, a relevant biomarker for wound infection, by entrapping urate oxidase in a dual-ionic-layer hydrogel membrane to filter out charged interfering agents. The biosensor exhibited a 4.5 µM limit of detection and selectivity even in artificial wound exudate. In the third paper we designed an interleukin-6 (IL6) OECT based biosensor able to detect the cytokine down to the pM regime in PBS buffer. The mechanism of detection relied on the specific binding between an aptamer, used as sensing unit on the gate electrode, and the IL6 in solution, allowing for detection ranging from physiological to pathological levels. In the last two papers we developed OECT based biosensors to be interfaced with the plant world. In the fourth paper we presented a glucose sensor, based on the enzyme glucose oxidase (GOx) to detect glucose export from chloroplasts. In particular, we demonstrated real-time glucose monitoring with temporal resolution of 1 minute in complex media. In the fifth paper, we developed implantable OECT-based sugar sensors for in vivo real-time monitoring of sugar transport in poplar trees. The biosensors presented a multienzyme-functionalized gate endowing the device with specificity towards glucose and sucrose. Most notably, the OECT sensors did not cause a significant wound response in the plant, allowing us to demonstrate that OECT-based sensors are attractive tools for studying transport kinetics in plants, in vivo and real-time.
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| 8. |
- Diacci, Chiara, et al.
(författare)
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Organic Electrochemical Transistor Aptasensor for Interleukin-6 Detection
- 2023
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252.
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Forskningsöversikt (refereegranskat)abstract
- We demonstrate an organic electrochemical transistor (OECT) biosensor for the detection of interleukin 6 (IL6), an important biomarker associated with various pathological processes, including chronic inflammation, inflammaging, cancer, and severe COVID-19 infection. The biosensor is functionalized with oligonucleotide aptamers engineered to bind specifically IL6. We developed an easy functionalization strategy based on gold nanoparticles deposited onto a poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonate (PEDOT:PSS) gate electrode for the subsequent electrodeposition of thiolated aptamers. During this functionalization step, the reduction of sulfide bonds allows for simultaneous deposition of a blocking agent. A detection range from picomolar to nanomolar concentrations for IL6 was achieved, and the selectivity of the device was assessed against Tumor Necrosis Factor (TNF), another cytokine involved in the inflammatory processes.
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| 9. |
- Diacci, Chiara, et al.
(författare)
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Real-Time Monitoring of Glucose Export from Isolated Chloroplasts Using an Organic Electrochemical Transistor
- 2020
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Ingår i: Advanced Materials Technologies. - : Wiley-VCH Verlagsgesellschaft. - 2365-709X. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- Biosensors based on organic electrochemical transistors (OECT) are attractive devices for real-time monitoring of biological processes. The direct coupling between the channel of the OECT and the electrolyte enables intimate interfacing with biological environments at the same time bringing signal amplification and fast sensor response times. So far, these devices are mainly applied to mammalian systems; cells or body fluids for the development of diagnostics and various health status monitoring technology. Yet, no direct detection of biomolecules from cells or organelles is reported. Here, an OECT glucose sensor applied to chloroplasts, which are the plant organelles responsible for the light-to-chemical energy conversion of the photosynthesis, is reported. Real-time monitoring of glucose export from chloroplasts in two distinct metabolic phases is demonstrated and the transfer dynamics with a time resolution of 1 min is quantified, thus reaching monitoring dynamics being an order of magnitude better than conventional methods.
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| 10. |
- Galliani, Marina, et al.
(författare)
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Flexible Printed Organic Electrochemical Transistors for the Detection of Uric Acid in Artificial Wound Exudate
- 2020
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Ingår i: Advanced Materials Interfaces. - : Wiley-VCH Verlag. - 2196-7350. ; 7:23
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Tidskriftsartikel (refereegranskat)abstract
- Low-cost, minimally invasive sensors able to provide real-time monitoring of wound infection can enable the optimization of healthcare resources in chronic wounds management. Here, a novel printed organic electrochemical transistors (OECT) biosensor for monitoring uric acid (UA), a bacterial infection biomarker in wounds, is demonstrated in artificial wound exudate. The sensor exploits the enzymatic conversion of UA to 5-hydroxyisourate, catalyzed by Uricase entrapped in a dual-ionic-layer hydrogel membrane casted onto the gate. The sensor response is based on the catalytic oxidation of the hydrogen peroxide, generated as part of the Uricase regeneration process, at the Pt modified gate. The proposed dual membrane avoids the occurrence of nonspecific faradic reactions as, for example, the direct oxidation of UA or other electroactive molecules that would introduce a potentially false negative response. The biosensor is robust and its response is reproducible both in phosphate buffer saline and in complex solutions mimicking the wound exudate. The sensor has a high sensitivity in the range encompassing the pathological levels of UA in wounds (<200 μm) exhibiting a limit of detection of 4.5 μm in artificial wound exudate. All these characteristics make this OECT-based biosensor attractive for wound monitoring interfaced to the patient.
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