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| 2. |
- Berto, Marcello, et al.
(författare)
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Biorecognition in Organic Field Effect Transistors Biosensors: The Role of the Density of States of the Organic Semiconductor
- 2016
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Ingår i: ANALYTICAL CHEMISTRY. - : AMER CHEMICAL SOC. - 0003-2700 .- 1520-6882. ; 88:24, s. 12330-12338
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Tidskriftsartikel (refereegranskat)abstract
- Biorecognition is a central event in biological processes in the living systems that is also widely exploited in technological and health applications. We demonstrate that the Electrolyte Gated Organic Field Effect Transistor (EGOFET) is an ultrasensitive and specific device that allows us to quantitatively assess the thermodynamics of biomolecular recognition between a human antibody and its antigen, namely, the inflammatory cytokine TNF alpha at the solid/liquid interface. The EGOFET biosensor exhibits a superexponential response at TNF alpha concentration below 1 nM with a minimum detection level of 100 pM. The sensitivity of the device depends on the analyte concentration, reaching a maximum in the range of clinically relevant TNF alpha concentrations when the EGOFET is operated in the subthreshold regime. At concentrations greater than 1 nM the response scales linearly with the concentration. The sensitivity and the dynamic range are both modulated by the gate voltage. These results are explained by establishing the correlation between the sensitivity and the density of states (DOS) of the organic semiconductor. Then, the superexponential response arises from the energy-dependence of the tail of the DOS of the HOMO level. From the gate voltage-dependent response, we extract the binding constant, as well as the changes of the surface charge and the effective capacitance accompanying biorecognition at the electrode surface. Finally, we demonstrate the detection of TNF alpha in human-plasma derived samples as an example for point-of-care application.
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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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