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15 pages, 3355 KiB

Open AccessArticle

Portable Measurement System for the Characterization of Capacitive Field-Effect Sensors

by Tobias Karschuck, Stefan Schmidt, Stefan Achtsnicht, Joey Ser, Ismail Bouarich, Georges Aboutass, Arshak Poghossian, Patrick H. Wagner and Michael J. Schöning

Sensors 2025, 25(9), 2681; https://doi.org/10.3390/s25092681 - 24 Apr 2025

Viewed by 670

Abstract

A user-friendly, portable, low-cost readout system for the on-site or point-of-care characterization of chemo- and biosensors based on an electrolyte–insulator–semiconductor capacitor (EISCAP) has been developed using a thumb-drive-sized commercial impedance analyzer. The system is controlled by a custom Python script and allows to [...] Read more.

A user-friendly, portable, low-cost readout system for the on-site or point-of-care characterization of chemo- and biosensors based on an electrolyte–insulator–semiconductor capacitor (EISCAP) has been developed using a thumb-drive-sized commercial impedance analyzer. The system is controlled by a custom Python script and allows to characterize EISCAP sensors with different methods (impedance spectra, capacitance-voltage, and constant-capacitance modes), which are selected in a user interface. The performance of the portable readout system was evaluated by pH measurements and the detection of the antibiotic penicillin, hereby using EISCAPs consisting of Al/p-Si/SiO₂/Ta₂O₅ structures and compared to the results obtained with a stationary commercial impedance analyzer. Both the portable and the commercial systems provide very similar results with almost perfectly overlapping recorded EISCAP signals. The new portable system can accelerate the transition of EISCAP sensors from research laboratories to commercial end-user devices. Full article

(This article belongs to the Special Issue Sensors from Miniaturization of Analytical Instruments (2nd Edition))

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32 pages, 4362 KiB

Open AccessArticle

Facile Purification and Use of Tobamoviral Nanocarriers for Antibody-Mediated Display of a Two-Enzyme System

by Tim Wendlandt, Claudia Koch, Beate Britz, Anke Liedek, Nora Schmidt, Stefan Werner, Yuri Gleba, Farnoosh Vahidpour, Melanie Welden, Arshak Poghossian, Michael J. Schöning, Fabian J. Eber, Holger Jeske and Christina Wege

Viruses 2023, 15(9), 1951; https://doi.org/10.3390/v15091951 - 19 Sep 2023

Cited by 3 | Viewed by 2717

Abstract

Immunosorbent turnip vein clearing virus (TVCV) particles displaying the IgG-binding domains D and E of Staphylococcus aureus protein A (PA) on every coat protein (CP) subunit (TVCV_PA) were purified from plants via optimized and new protocols. The latter used polyethylene glycol [...] Read more.

Immunosorbent turnip vein clearing virus (TVCV) particles displaying the IgG-binding domains D and E of Staphylococcus aureus protein A (PA) on every coat protein (CP) subunit (TVCV_PA) were purified from plants via optimized and new protocols. The latter used polyethylene glycol (PEG) raw precipitates, from which virions were selectively re-solubilized in reverse PEG concentration gradients. This procedure improved the integrity of both TVCV_PA and the wild-type subgroup 3 tobamovirus. TVCV_PA could be loaded with more than 500 IgGs per virion, which mediated the immunocapture of fluorescent dyes, GFP, and active enzymes. Bi-enzyme ensembles of cooperating glucose oxidase and horseradish peroxidase were tethered together on the TVCV_PA carriers via a single antibody type, with one enzyme conjugated chemically to its Fc region, and the other one bound as a target, yielding synthetic multi-enzyme complexes. In microtiter plates, the TVCV_PA-displayed sugar-sensing system possessed a considerably increased reusability upon repeated testing, compared to the IgG-bound enzyme pair in the absence of the virus. A high coverage of the viral adapters was also achieved on Ta₂O₅ sensor chip surfaces coated with a polyelectrolyte interlayer, as a prerequisite for durable TVCV_PA-assisted electrochemical biosensing via modularly IgG-assembled sensor enzymes. Full article

(This article belongs to the Special Issue Tobamoviruses 2023)

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17 pages, 3056 KiB

Open AccessArticle

Detection of Acetoin and Diacetyl by a Tobacco Mosaic Virus-Assisted Field-Effect Biosensor

by Melanie Welden, Robin Severins, Arshak Poghossian, Christina Wege, Johannes Bongaerts, Petra Siegert, Michael Keusgen and Michael J. Schöning

Chemosensors 2022, 10(6), 218; https://doi.org/10.3390/chemosensors10060218 - 8 Jun 2022

Cited by 8 | Viewed by 3274

Abstract

Acetoin and diacetyl have a major impact on the flavor of alcoholic beverages such as wine or beer. Therefore, their measurement is important during the fermentation process. Until now, gas chromatographic techniques have typically been applied; however, these require expensive laboratory equipment and [...] Read more.

Acetoin and diacetyl have a major impact on the flavor of alcoholic beverages such as wine or beer. Therefore, their measurement is important during the fermentation process. Until now, gas chromatographic techniques have typically been applied; however, these require expensive laboratory equipment and trained staff, and do not allow for online monitoring. In this work, a capacitive electrolyte–insulator–semiconductor sensor modified with tobacco mosaic virus (TMV) particles as enzyme nanocarriers for the detection of acetoin and diacetyl is presented. The enzyme acetoin reductase from Alkalihalobacillus clausii DSM 8716^T is immobilized via biotin–streptavidin affinity, binding to the surface of the TMV particles. The TMV-assisted biosensor is electrochemically characterized by means of leakage–current, capacitance–voltage, and constant capacitance measurements. In this paper, the novel biosensor is studied regarding its sensitivity and long-term stability in buffer solution. Moreover, the TMV-assisted capacitive field-effect sensor is applied for the detection of diacetyl for the first time. The measurement of acetoin and diacetyl with the same sensor setup is demonstrated. Finally, the successive detection of acetoin and diacetyl in buffer and in diluted beer is studied by tuning the sensitivity of the biosensor using the pH value of the measurement solution. Full article

(This article belongs to the Special Issue Nanostructured Devices for Biochemical Sensing)

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14 pages, 2825 KiB

Open AccessEditor’s ChoiceArticle

Field-Effect Capacitors Decorated with Ligand-Stabilized Gold Nanoparticles: Modeling and Experiments

by Arshak Poghossian, Tobias Karschuck, Patrick Wagner and Michael J. Schöning

Biosensors 2022, 12(5), 334; https://doi.org/10.3390/bios12050334 - 13 May 2022

Cited by 6 | Viewed by 2946

Abstract

Nanoparticles are recognized as highly attractive tunable materials for designing field-effect biosensors with enhanced performance. In this work, we present a theoretical model for electrolyte-insulator-semiconductor capacitors (EISCAP) decorated with ligand-stabilized charged gold nanoparticles. The charged AuNPs are taken into account as additional, nanometer-sized [...] Read more.

Nanoparticles are recognized as highly attractive tunable materials for designing field-effect biosensors with enhanced performance. In this work, we present a theoretical model for electrolyte-insulator-semiconductor capacitors (EISCAP) decorated with ligand-stabilized charged gold nanoparticles. The charged AuNPs are taken into account as additional, nanometer-sized local gates. The capacitance-voltage (C–V) curves and constant-capacitance (ConCap) signals of the AuNP-decorated EISCAPs have been simulated. The impact of the AuNP coverage on the shift of the C–V curves and the ConCap signals was also studied experimentally on Al–p-Si–SiO₂ EISCAPs decorated with positively charged aminooctanethiol-capped AuNPs. In addition, the surface of the EISCAPs, modified with AuNPs, was characterized by scanning electron microscopy for different immobilization times of the nanoparticles. Full article

(This article belongs to the Special Issue Biosensors in Nanotechnology)

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16 pages, 3825 KiB

Open AccessArticle

Towards Multi-Analyte Detection with Field-Effect Capacitors Modified with Tobacco Mosaic Virus Bioparticles as Enzyme Nanocarriers

by Melanie Welden, Arshak Poghossian, Farnoosh Vahidpour, Tim Wendlandt, Michael Keusgen, Christina Wege and Michael J. Schöning

Biosensors 2022, 12(1), 43; https://doi.org/10.3390/bios12010043 - 14 Jan 2022

Cited by 16 | Viewed by 4137

Abstract

Utilizing an appropriate enzyme immobilization strategy is crucial for designing enzyme-based biosensors. Plant virus-like particles represent ideal nanoscaffolds for an extremely dense and precise immobilization of enzymes, due to their regular shape, high surface-to-volume ratio and high density of surface binding sites. In [...] Read more.

Utilizing an appropriate enzyme immobilization strategy is crucial for designing enzyme-based biosensors. Plant virus-like particles represent ideal nanoscaffolds for an extremely dense and precise immobilization of enzymes, due to their regular shape, high surface-to-volume ratio and high density of surface binding sites. In the present work, tobacco mosaic virus (TMV) particles were applied for the co-immobilization of penicillinase and urease onto the gate surface of a field-effect electrolyte-insulator-semiconductor capacitor (EISCAP) with a p-Si-SiO₂-Ta₂O₅ layer structure for the sequential detection of penicillin and urea. The TMV-assisted bi-enzyme EISCAP biosensor exhibited a high urea and penicillin sensitivity of 54 and 85 mV/dec, respectively, in the concentration range of 0.1–3 mM. For comparison, the characteristics of single-enzyme EISCAP biosensors modified with TMV particles immobilized with either penicillinase or urease were also investigated. The surface morphology of the TMV-modified Ta₂O₅-gate was analyzed by scanning electron microscopy. Additionally, the bi-enzyme EISCAP was applied to mimic an XOR (Exclusive OR) enzyme logic gate. Full article

(This article belongs to the Special Issue Biosensors: 10th Anniversary Feature Papers)

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17 pages, 3241 KiB

Open AccessArticle

An Array of On-Chip Integrated, Individually Addressable Capacitive Field-Effect Sensors with Control Gate: Design and Modelling

by Arshak Poghossian, Rene Welden, Vahe V. Buniatyan and Michael J. Schöning

Sensors 2021, 21(18), 6161; https://doi.org/10.3390/s21186161 - 14 Sep 2021

Cited by 6 | Viewed by 2289

Abstract

The on-chip integration of multiple biochemical sensors based on field-effect electrolyte-insulator-semiconductor capacitors (EISCAP) is challenging due to technological difficulties in realization of electrically isolated EISCAPs on the same Si chip. In this work, we present a new simple design for an array of [...] Read more.

The on-chip integration of multiple biochemical sensors based on field-effect electrolyte-insulator-semiconductor capacitors (EISCAP) is challenging due to technological difficulties in realization of electrically isolated EISCAPs on the same Si chip. In this work, we present a new simple design for an array of on-chip integrated, individually electrically addressable EISCAPs with an additional control gate (CG-EISCAP). The existence of the CG enables an addressable activation or deactivation of on-chip integrated individual CG-EISCAPs by simple electrical switching the CG of each sensor in various setups, and makes the new design capable for multianalyte detection without cross-talk effects between the sensors in the array. The new designed CG-EISCAP chip was modelled in so-called floating/short-circuited and floating/capacitively-coupled setups, and the corresponding electrical equivalent circuits were developed. In addition, the capacitance-voltage curves of the CG-EISCAP chip in different setups were simulated and compared with that of a single EISCAP sensor. Moreover, the sensitivity of the CG-EISCAP chip to surface potential changes induced by biochemical reactions was simulated and an impact of different parameters, such as gate voltage, insulator thickness and doping concentration in Si, on the sensitivity has been discussed. Full article

(This article belongs to the Special Issue Field-Effect Sensors: From pH Sensing to Biosensing)

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16 pages, 3790 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Capacitive Field-Effect Biosensor Studying Adsorption of Tobacco Mosaic Virus Particles

by Melanie Jablonski, Arshak Poghossian, Robin Severins, Michael Keusgen, Christina Wege and Michael J. Schöning

Micromachines 2021, 12(1), 57; https://doi.org/10.3390/mi12010057 - 6 Jan 2021

Cited by 24 | Viewed by 4299

Abstract

Plant virus-like particles, and in particular, tobacco mosaic virus (TMV) particles, are increasingly being used in nano- and biotechnology as well as for biochemical sensing purposes as nanoscaffolds for the high-density immobilization of receptor molecules. The sensitive parameters of TMV-assisted biosensors depend, among [...] Read more.

Plant virus-like particles, and in particular, tobacco mosaic virus (TMV) particles, are increasingly being used in nano- and biotechnology as well as for biochemical sensing purposes as nanoscaffolds for the high-density immobilization of receptor molecules. The sensitive parameters of TMV-assisted biosensors depend, among others, on the density of adsorbed TMV particles on the sensor surface, which is affected by both the adsorption conditions and surface properties of the sensor. In this work, Ta₂O₅-gate field-effect capacitive sensors have been applied for the label-free electrical detection of TMV adsorption. The impact of the TMV concentration on both the sensor signal and the density of TMV particles adsorbed onto the Ta₂O₅-gate surface has been studied systematically by means of field-effect and scanning electron microscopy methods. In addition, the surface density of TMV particles loaded under different incubation times has been investigated. Finally, the field-effect sensor also demonstrates the label-free detection of penicillinase immobilization as model bioreceptor on TMV particles. Full article

(This article belongs to the Special Issue FET and Field Effect-Based Sensors)

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32 pages, 4086 KiB

Open AccessReview

Capacitive Field-Effect EIS Chemical Sensors and Biosensors: A Status Report

by Arshak Poghossian and Michael J. Schöning

Sensors 2020, 20(19), 5639; https://doi.org/10.3390/s20195639 - 2 Oct 2020

Cited by 63 | Viewed by 9147

Abstract

Electrolyte-insulator-semiconductor (EIS) field-effect sensors belong to a new generation of electronic chips for biochemical sensing, enabling a direct electronic readout. The review gives an overview on recent advances and current trends in the research and development of chemical sensors and biosensors based on [...] Read more.

Electrolyte-insulator-semiconductor (EIS) field-effect sensors belong to a new generation of electronic chips for biochemical sensing, enabling a direct electronic readout. The review gives an overview on recent advances and current trends in the research and development of chemical sensors and biosensors based on the capacitive field-effect EIS structure—the simplest field-effect device, which represents a biochemically sensitive capacitor. Fundamental concepts, physicochemical phenomena underlying the transduction mechanism and application of capacitive EIS sensors for the detection of pH, ion concentrations, and enzymatic reactions, as well as the label-free detection of charged molecules (nucleic acids, proteins, and polyelectrolytes) and nanoparticles, are presented and discussed. Full article

(This article belongs to the Special Issue Biosensors – Recent Advances and Future Challenges)

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1 pages, 122 KiB

Open AccessAbstract

Adrenaline Bi-Enzyme Sensor Using Signal Amplification Principle to Support Adrenal Venous Sampling

by Denise Molinnus, Gabriel Hardt, Petra Siegert, Holger S. Willenberg, Fred Lisdat, Arshak Poghossian, Michael Keusgen and Michael J. Schöning

Proceedings 2017, 1(8), 717; https://doi.org/10.3390/proceedings1080717 - 18 Dec 2017

Viewed by 1790

Abstract

Primary aldosteronsim (PA) is the most frequent cause of secondary hypertension. [...] Full article

(This article belongs to the Proceedings of Proceedings of the 5th International Symposium on Sensor Science (I3S 2017))

1 pages, 124 KiB

Open AccessAbstract

Label-Free DNA Detection with Capacitive Field-Effect Devices—Challenges and Opportunities

by Michael J. Schöning, Thomas S. Bronder, Chunsheng Wu, Sabrina Scheja, Max Jessing, Christoph Metzger-Boddien, Michael Keusgen and Arshak Poghossian

Proceedings 2017, 1(8), 719; https://doi.org/10.3390/proceedings1080719 - 24 Nov 2017

Viewed by 1825

Abstract

Field-effect EIS (electrolyte-insulator-semiconductor) sensors modified with a positively charged weak polyelectrolyte layer have been applied for the electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge. [...] Full article

(This article belongs to the Proceedings of Proceedings of the 5th International Symposium on Sensor Science (I3S 2017))

4 pages, 739 KiB

Open AccessProceeding Paper

Field-Effect Biosensors Modified with Tobacco Mosaic Virus Nanotubes as Enzyme Nanocarrier

by Melanie Jablonski, Claudia Koch, Thomas S. Bronder, Arshak Poghossian, Christina Wege and Michael J. Schöning

Proceedings 2017, 1(4), 505; https://doi.org/10.3390/proceedings1040505 - 8 Aug 2017

Cited by 3 | Viewed by 2963

Abstract

A new concept for the development of semiconductor field-effect biosensors by modification of a gate surface with tobacco mosaic virus (TMV) nanotubes, serving as enzyme nanocarrier, is presented. TMV nanotubes enable an immobilization of a high amount of enzymes without substantial loss of [...] Read more.

A new concept for the development of semiconductor field-effect biosensors by modification of a gate surface with tobacco mosaic virus (TMV) nanotubes, serving as enzyme nanocarrier, is presented. TMV nanotubes enable an immobilization of a high amount of enzymes without substantial loss of their activity, resulting in an enhanced biosensor performance. This approach has been experimentally demonstrated by realizing a capacitive field-effect penicillin biosensor using TMV nanotubes functionalized with the enzyme penicillinase as model system. Full article

(This article belongs to the Proceedings of Proceedings of Eurosensors 2017, Paris, France, 3–6 September 2017)

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3 pages, 385 KiB

Open AccessProceeding Paper

Detection of Adrenaline Based on Bioelectrocatalytical System to Support Tumor Diagnostic Technology

by Denise Molinnus, Gabriel Hardt, Larissa Käver, Holger S. Willenberg, Arshak Poghossian, Michael Keusgen and Michael J. Schöning

Proceedings 2017, 1(4), 506; https://doi.org/10.3390/proceedings1040506 - 7 Aug 2017

Cited by 3 | Viewed by 2400

Abstract

An amperometric biosensor based on the bioelectrocatalytic measurement principle for the detection of adrenaline has been developed. The adrenaline sensor has been prepared by modification of a platinum thin-film electrode with a pyrroloquinoline quinone-dependent glucose dehydrogenase. The enzyme was immobilized via cross-linking method. [...] Read more.

An amperometric biosensor based on the bioelectrocatalytic measurement principle for the detection of adrenaline has been developed. The adrenaline sensor has been prepared by modification of a platinum thin-film electrode with a pyrroloquinoline quinone-dependent glucose dehydrogenase. The enzyme was immobilized via cross-linking method. Lower detection limit of 1 nM of adrenaline has been achieved by measuring at physiological level at pH 7.4. Full article

(This article belongs to the Proceedings of Proceedings of Eurosensors 2017, Paris, France, 3–6 September 2017)

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8 pages, 302 KiB

Open AccessArticle

Functional Testing and Characterisation of ISFETs on Wafer Level by Means of a Micro-droplet Cell

by Arshak Poghossian, Kerstin Schumacher, Joachim P. Kloock, Christian Rosenkranz, Joachim W. Schultze, Mattea Müller-Veggian and Michael J. Schöning

Sensors 2006, 6(4), 397-404; https://doi.org/10.3390/s6040397 - 7 Apr 2006

Cited by 4 | Viewed by 11186

Abstract

A wafer-level functionality testing and characterisation system for ISFETs (ion-sensitive field-effect transistor) is realised by means of integration of a specifically designedcapillary electrochemical micro-droplet cell into a commercial wafer prober-station. Thedeveloped system allows the identification and selection of “good” ISFETs at the earlieststage [...] Read more.

A wafer-level functionality testing and characterisation system for ISFETs (ion-sensitive field-effect transistor) is realised by means of integration of a specifically designedcapillary electrochemical micro-droplet cell into a commercial wafer prober-station. Thedeveloped system allows the identification and selection of “good” ISFETs at the earlieststage and to avoid expensive bonding, encapsulation and packaging processes for non-functioning ISFETs and thus, to decrease costs, which are wasted for bad dies. Thedeveloped system is also feasible for wafer-level characterisation of ISFETs in terms ofsensitivity, hysteresis and response time. Additionally, the system might be also utilised forwafer-level testing of further electrochemical sensors. Full article

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9 pages, 251 KiB

Open AccessArticle

“Microstructured Nanostructures” – Nanostructuring by Means of Conventional Photolithography and Layer-expansion Technique

by Johannes Platen, Arshak Poghossian and Michael J. Schöning

Sensors 2006, 6(4), 361-369; https://doi.org/10.3390/S6040361 - 4 Apr 2006

Cited by 10 | Viewed by 8530

Abstract

A new and simple method for nanostructuring using conventionalphotolithography and layer expansion or pattern-size reduction technique is presented, whichcan further be applied for the fabrication of different nanostructures and nano-devices. Themethod is based on the conversion of a photolithographically patterned metal layer to [...] Read more.

A new and simple method for nanostructuring using conventionalphotolithography and layer expansion or pattern-size reduction technique is presented, whichcan further be applied for the fabrication of different nanostructures and nano-devices. Themethod is based on the conversion of a photolithographically patterned metal layer to ametal-oxide mask with improved pattern-size resolution using thermal oxidation. With thistechnique, the pattern size can be scaled down to several nanometer dimensions. Theproposed method is experimentally demonstrated by preparing nanostructures with differentconfigurations and layouts, like circles, rectangles, trapezoids, “fluidic-channel”-,“cantilever”- and meander-type structures. Full article

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11 pages, 536 KiB

Open AccessArticle

Integration of a Capacitive EIS Sensor into a FIA System for pH and Penicillin Determination

by David Rolka, Arshak Poghossian and Michael J. Schöning

Sensors 2004, 4(6), 84-94; https://doi.org/10.3390/s40670084 - 30 Aug 2004

Cited by 23 | Viewed by 10406

Abstract

A field-effect based capacitive EIS (electrolyte-insulator-semiconductor) sensor with a p-Si-SiO2-Ta2O5 structure has been successfully integrated into a commercial FIA (flow-injection analysis) system and system performances have been proven and optimised for pH and penicillin detection. A flow-through cell was designed taking into account [...] Read more.

A field-effect based capacitive EIS (electrolyte-insulator-semiconductor) sensor with a p-Si-SiO2-Ta2O5 structure has been successfully integrated into a commercial FIA (flow-injection analysis) system and system performances have been proven and optimised for pH and penicillin detection. A flow-through cell was designed taking into account the requirement of a variable internal volume (from 12 μl up to 48 μl) as well as an easy replacement of the EIS sensor. FIA parameters (sample volume, flow rate, distance between the injection valve and the EIS sensor) have been optimised in terms of high sensitivity and reproducibility as well as a minimum dispersion of the injected sample zone. An acceptable compromise between different FIA parameters has been found. For the cell design used in this study, best results have been achieved with a flow rate of 1.4 ml/min, distance between the injection valve and the EIS sensor of 6.5 cm, probe volume of 0.75 ml, cell internal volume of 12 μl. A sample throughput of at least 15 samples/h was typically obtained. Full article

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