@article{PoghossianKarschuckWagneretal.2022,
  author    = {Poghossian, Arshak and Karschuck, Tobias and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Field-Effect Capacitors Decorated with Ligand-Stabilized Gold Nanoparticles: Modeling and Experiments},
  series = {Biosensors},
  volume    = {12},
  journal   = {Biosensors},
  number    = {5},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-6374},
  doi       = {10.3390/bios12050334},
  pages     = {Artikel 334},
  year      = {2022},
  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 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.},
  language  = {en}
}
@article{KarschuckKaulenPoghossianetal.2021,
  author    = {Karschuck, Tobias and Kaulen, Corinna and Poghossian, Arshak and Wagner, Patrick H. and Sch{\"o}ning, Michael Josef},
  title     = {Gold nanoparticle-modified capacitive field-effect sensors: Studying the surface density of nanoparticles and coupling of charged polyelectrolyte macromolecules},
  series = {Electrochemical Science Advances},
  volume    = {2},
  journal   = {Electrochemical Science Advances},
  number    = {5},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0938-5193},
  doi       = {10.1002/elsa.202100179},
  pages     = {10 Seiten},
  year      = {2021},
  abstract  = {The coupling of ligand-stabilized gold nanoparticles with field-effect devices offers new possibilities for label-free biosensing. In this work, we study the immobilization of aminooctanethiol-stabilized gold nanoparticles (AuAOTs) on the silicon dioxide surface of a capacitive field-effect sensor. The terminal amino group of the AuAOT is well suited for the functionalization with biomolecules. The attachment of the positively-charged AuAOTs on a capacitive field-effect sensor was detected by direct electrical readout using capacitance-voltage and constant capacitance measurements. With a higher particle density on the sensor surface, the measured signal change was correspondingly more pronounced. The results demonstrate the ability of capacitive field-effect sensors for the non-destructive quantitative validation of nanoparticle immobilization. In addition, the electrostatic binding of the polyanion polystyrene sulfonate to the AuAOT-modified sensor surface was studied as a model system for the label-free detection of charged macromolecules. Most likely, this approach can be transferred to the label-free detection of other charged molecules such as enzymes or antibodies.},
  language  = {en}
}
@article{KarschuckSchmidtAchtsnichtetal.2023,
  author    = {Karschuck, Tobias and Schmidt, Stefan and Achtsnicht, Stefan and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Multiplexing system for automated characterization of a capacitive field-effect sensor array},
  series = {Physica Status Solidi A},
  volume    = {220},
  journal   = {Physica Status Solidi A},
  number    = {22},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6300 (Print)},
  doi       = {10.1002/pssa.202300265},
  pages     = {7 Seiten},
  year      = {2023},
  abstract  = {In comparison to single-analyte devices, multiplexed systems for a multianalyte detection offer a reduced assay time and sample volume, low cost, and high throughput. Herein, a multiplexing platform for an automated quasi-simultaneous characterization of multiple (up to 16) capacitive field-effect sensors by the capacitive-voltage (C-V) and the constant-capacitance (ConCap) mode is presented. The sensors are mounted in a newly designed multicell arrangement with one common reference electrode and are electrically connected to the impedance analyzer via the base station. A Python script for the automated characterization of the sensors executes the user-defined measurement protocol. The developed multiplexing system is tested for pH measurements and the label-free detection of ligand-stabilized, charged gold nanoparticles.},
  language  = {en}
}
@article{KarschuckPoghossianSeretal.2024,
  author    = {Karschuck, Tobias and Poghossian, Arshak and Ser, Joey and Tsokolakyan, Astghik and Achtsnicht, Stefan and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Capacitive model of enzyme-modified field-effect biosensors: Impact of enzyme coverage},
  series = {Sensors and Actuators B: Chemical},
  volume    = {408},
  journal   = {Sensors and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005 (Print)},
  doi       = {10.1016/j.snb.2024.135530},
  pages     = {12 Seiten},
  year      = {2024},
  abstract  = {Electrolyte-insulator-semiconductor capacitors (EISCAP) belong to field-effect sensors having an attractive transducer architecture for constructing various biochemical sensors. In this study, a capacitive model of enzyme-modified EISCAPs has been developed and the impact of the surface coverage of immobilized enzymes on its capacitance-voltage and constant-capacitance characteristics was studied theoretically and experimentally. The used multicell arrangement enables a multiplexed electrochemical characterization of up to sixteen EISCAPs. Different enzyme coverages have been achieved by means of parallel electrical connection of bare and enzyme-covered single EISCAPs in diverse combinations. As predicted by the model, with increasing the enzyme coverage, both the shift of capacitance-voltage curves and the amplitude of the constant-capacitance signal increase, resulting in an enhancement of analyte sensitivity of the EISCAP biosensor. In addition, the capability of the multicell arrangement with multi-enzyme covered EISCAPs for sequentially detecting multianalytes (penicillin and urea) utilizing the enzymes penicillinase and urease has been experimentally demonstrated and discussed.},
  language  = {en}
}