TY  - JOUR
A1  - Rabehi, Amine
A1  - Garlan, Benjamin
A1  - Achtsnicht, Stefan
A1  - Krause, Hans-Joachim
A1  - Offenhäusser, Andreas
A1  - Ngo, Kieu
A1  - Neveu, Sophie
A1  - Graff-Dubois, Stephanie
A1  - Kokabi, Hamid
T1  - Magnetic detection structure for Lab-on-Chip applications based on the frequency mixing technique
JF  - Sensors
N2  - A magnetic frequency mixing technique with a set of miniaturized planar coils was investigated for use with a completely integrated Lab-on-Chip (LoC) pathogen sensing system. The system allows the detection and quantification of superparamagnetic beads. Additionally, in terms of magnetic nanoparticle characterization ability, the system can be used for immunoassays using the beads as markers. Analytical calculations and simulations for both excitation and pick-up coils are presented; the goal was to investigate the miniaturization of simple and cost-effective planar spiral coils. Following these calculations, a Printed Circuit Board (PCB) prototype was designed, manufactured, and tested for limit of detection, linear response, and validation of theoretical concepts. Using the magnetic frequency mixing technique, a limit of detection of 15 µg/mL of 20 nm core-sized nanoparticles was achieved without any shielding.
KW  - Lab-on-Chip
KW  - magnetic sensing
KW  - frequency mixing
KW  - superparamagnetic nanoparticles
KW  - magnetic beads
Y1  - 2018
U6  - http://dx.doi.org/10.3390/s18061747
SN  - 1424-8220
VL  - 18
IS  - 6
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Pourshahidi, Ali Mohammad
A1  - Engelmann, Ulrich M.
A1  - Offenhäusser, Andreas
A1  - Krause, Hans-Joachim
T1  - Resolving ambiguities in core size determination of magnetic nanoparticles from magnetic frequency mixing data
JF  - Journal of Magnetism and Magnetic Materials
N2  - Frequency mixing magnetic detection (FMMD) has been widely utilized as a measurement technique in magnetic immunoassays. It can also be used for the characterization and distinction (also known as “colourization”) of different types of magnetic nanoparticles (MNPs) based on their core sizes. In a previous work, it was shown that the large particles contribute most of the FMMD signal. This leads to ambiguities in core size determination from fitting since the contribution of the small-sized particles is almost undetectable among the strong responses from the large ones. In this work, we report on how this ambiguity can be overcome by modelling the signal intensity using the Langevin model in thermodynamic equilibrium including a lognormal core size distribution fL(dc,d0,σ) fitted to experimentally measured FMMD data of immobilized MNPs. For each given median diameter d0, an ambiguous amount of best-fitting pairs of parameters distribution width σ and number of particles Np with R2 > 0.99 are extracted. By determining the samples’ total iron mass, mFe, with inductively coupled plasma optical emission spectrometry (ICP-OES), we are then able to identify the one specific best-fitting pair (σ, Np) one uniquely. With this additional externally measured parameter, we resolved the ambiguity in core size distribution and determined the parameters (d0, σ, Np) directly from FMMD measurements, allowing precise MNPs sample characterization.
Y1  - 2022
U6  - http://dx.doi.org/10.1016/j.jmmm.2022.169969
SN  - 0304-8853
VL  - 563
IS  - In progress, Art. No. 169969
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Pourshahidi, Ali Mohammad
A1  - Achtsnicht, Stefan
A1  - Offenhäusser, Andreas
A1  - Krause, Hans-Joachim
ED  - Offenhäusser, Andreas
T1  - Frequency Mixing Magnetic Detection Setup Employing Permanent Ring Magnets as a Static Offset Field Source
JF  - Sensors
N2  - Frequency mixing magnetic detection (FMMD) has been explored for its applications in fields of magnetic biosensing, multiplex detection of magnetic nanoparticles (MNP) and the determination of core size distribution of MNP samples. Such applications rely on the application of a static offset magnetic field, which is generated traditionally with an electromagnet. Such a setup requires a current source, as well as passive or active cooling strategies, which directly sets a limitation based on the portability aspect that is desired for point of care (POC) monitoring applications. In this work, a measurement head is introduced that involves the utilization of two ring-shaped permanent magnets to generate a static offset magnetic field. A steel cylinder in the ring bores homogenizes the field. By variation of the distance between the ring magnets and of the thickness of the steel cylinder, the magnitude of the magnetic field at the sample position can be adjusted. Furthermore, the measurement setup is compared to the electromagnet offset module based on measured signals and temperature behavior.
KW  - magnetic sensors
KW  - biosensors
KW  - frequency mixing magnetic detection
KW  - magnetic nanoparticles
Y1  - 2022
U6  - http://dx.doi.org/10.3390/s22228776
SN  - 1424-8220
VL  - 22
IS  - 22
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Pourshahidi, Ali Mohammad
A1  - Achtsnicht, Stefan
A1  - Nambipareechee, Mrinal Murali
A1  - Offenhäusser, Andreas
A1  - Krause, Hans-Joachim
T1  - Multiplex detection of magnetic beads using offset field dependent frequency mixing magnetic detection
JF  - Sensors
N2  - Magnetic immunoassays employing Frequency Mixing Magnetic Detection (FMMD) have recently become increasingly popular for quantitative detection of various analytes. Simultaneous analysis of a sample for two or more targets is desirable in order to reduce the sample amount, save consumables, and save time. We show that different types of magnetic beads can be distinguished according to their frequency mixing response to a two-frequency magnetic excitation at different static magnetic offset fields. We recorded the offset field dependent FMMD response of two different particle types at frequencies ƒ₁ + n⋅ƒ₂, n = 1, 2, 3, 4 with ƒ₁ = 30.8 kHz and ƒ₂ = 63 Hz. Their signals were clearly distinguishable by the locations of the extremes and zeros of their responses. Binary mixtures of the two particle types were prepared with different mixing ratios. The mixture samples were analyzed by determining the best linear combination of the two pure constituents that best resembled the measured signals of the mixtures. Using a quadratic programming algorithm, the mixing ratios could be determined with an accuracy of greater than 14%. If each particle type is functionalized with a different antibody, multiplex detection of two different analytes becomes feasible.
KW  - colorization
KW  - multiplex detection
KW  - frequency mixing magnetic detection
KW  - magnetic nanoparticles
Y1  - 2021
U6  - http://dx.doi.org/10.3390/s21175859
SN  - 1424-8220
N1  - This article belongs to the Special Issue "Advanced Nanomaterial-Based Sensors for Biomedical Applications"
VL  - 21
IS  - 17
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Polen, T.
A1  - Krämer, Marco
A1  - Bongaerts, Johannes
A1  - Wubbolts, Marcel
A1  - Wendisch, V. F.
T1  - The global gene expression response of Escherichia coli to L-phenylalanine
JF  - Journal of biotechnology
Y1  - 2005
SN  - 1873-4863 (E-Journal); 0168-1656 (Print)
VL  - Vol. 115
IS  - Iss. 3
SP  - 221
EP  - 237
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Yoshinobu, Tatsuo
A1  - Simonis, A.
A1  - Ecken, H.
A1  - Lüth, Hans
A1  - Schöning, Michael Josef
T1  - Penicillin detection by means of field-effect based sensors: EnFET, capacitive EIS sensor or LAPS?
JF  - Sensors and Actuators B. 78 (2001), H. 1-3
Y1  - 2001
SN  - 0925-4005
SP  - 237
EP  - 242
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Yoshinobu, Tatsuo
A1  - Schöning, Michael Josef
T1  - Flow-velocity microsensors based on semiconductor field-effect structures
JF  - Sensors. 3 (2003), H. 7
Y1  - 2003
SN  - 1424-8220
SP  - 202
EP  - 212
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Yoshinobu, T.
A1  - Simonis, A.
A1  - Ecken, H.
A1  - Lüth, H.
A1  - Schöning, Michael Josef
T1  - Penicillin detection by means of field-effect based sensors: EnFET, capacitive EIS sensor or LAPS?
JF  - Proceedings : Copenhagen, Denmark, 27 - 30 August 2000 / [ed.: R. de Reus ...]
Y1  - 2000
SN  - 87-89935-50-0
N1  - Eurosensors ; (14, 2000, København) ; Eurosensors ; (14 : ; 2000.08.27-30 : ; Copenhagen) ; European Conference on Solid-State Transducers ; (14 : ; 2000.08.27-30 : ; Copenhagen)
SP  - 27
EP  - 30
PB  - MIC, Mikroelektronik Centret
CY  - Lyngby, Denmark
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Werner, Frederik
A1  - Buniatyan, V. V.
A1  - Wagner, Torsten
A1  - Miamoto, K.
A1  - Yoshinobu, T.
A1  - Schöning, Michael Josef
T1  - Towards addressability of light-addressable potentiometric sensors: Shunting effect of non-illuminated region and cross-talk
JF  - Sensor and Actuators B: Chemical
N2  - The LAPS (light-addressable potentiometric sensor) platform is one of the most attractive approaches for chemical and biological sensing with many applications ranging from pH and ion/analyte concentration measurements up to cell metabolism detection and chemical imaging. However, although it is generally accepted that LAPS measurements are spatially resolved, the light-addressability feature of LAPS devices has not been discussed in detail so far. In this work, an extended electrical equivalent-circuit model of the LAPS has been presented, which takes into account possible cross-talk effects due to the capacitive coupling of the non-illuminated region. A shunting effect of the non-illuminated area on the measured photocurrent and addressability of LAPS devices has been studied. It has been shown, that the measured photocurrent will be determined not only by the local interfacial potential in the illuminated region but also by possible interfacial potential changes in the non-illuminated region, yielding cross-talk effects. These findings were supported by the experimental investigations of a penicillin-sensitive multi-spot LAPS and a metal-insulator-semiconductor LAPS as model systems.
Y1  - 2017
U6  - http://dx.doi.org/10.1016/j.snb.2017.01.047
SN  - 0925-4005
IS  - 244
SP  - 1071
EP  - 1079
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Welden, Rene
A1  - Buniatyan, Vahe V.
A1  - Schöning, Michael Josef
T1  - An Array of On-Chip Integrated, Individually Addressable Capacitive Field-Effect Sensors with Control Gate: Design and Modelling
JF  - Sensors
N2  - 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.
KW  - equivalent circuit
KW  - multianalyte detection
KW  - control gate
KW  - on-chip integrated addressable EISCAP sensors
KW  - capacitive field-effect sensor
Y1  - 2021
U6  - http://dx.doi.org/10.3390/s21186161
SN  - 1424-8220
N1  - This article belongs to the Special Issue "Field-Effect Sensors: From pH Sensing to Biosensing"
VL  - 21
IS  - 18
SP  - 17
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Weil, M. H.
A1  - Bäcker, Matthias
A1  - Mayer, D.
A1  - Schöning, Michael Josef
T1  - Field-effect Devices Functionalised with Gold-Nanoparticle/Macromolecule Hybrids: New Opportunities for a Label-Free Biosensing
JF  - Procedia Engineering
N2  - Field-effect capacitive electrolyte-insulator-semiconductor (EIS) sensors functionalised with citrate-capped gold nanoparticles (AuNP) have been used for the electrostatic detection of macromolecules by their intrinsic molecular charge. The EIS sensor detects the charge changes in the AuNP/macromolecule hybrids induced by the adsorption or binding events. A feasibility of the proposed detection scheme has been exemplary demonstrated by realising EIS sensors for the detection of poly-D-lysine molecules.
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.proeng.2012.09.136
SN  - 1877-7058
N1  - Part of special issue "26th European Conference on Solid-State Transducers, EUROSENSOR 2012"
IS  - 47
SP  - 273
EP  - 276
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Weil, M.
A1  - Cherstvy, A. G.
A1  - Schöning, Michael Josef
T1  - Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices
JF  - Analytical and bioanalytical chemistry
N2  - The semiconductor field-effect platform represents a powerful tool for detecting the adsorption and binding of charged macromolecules with direct electrical readout. In this work, a capacitive electrolyte–insulator–semiconductor (EIS) field-effect sensor consisting of an Al-p-Si-SiO2 structure has been applied for real-time in situ electrical monitoring of the layer-by-layer formation of polyelectrolyte (PE) multilayers (PEM). The PEMs were deposited directly onto the SiO2 surface without any precursor layer or drying procedures. Anionic poly(sodium 4-styrene sulfonate) and cationic weak polyelectrolyte poly(allylamine hydrochloride) have been chosen as a model system. The effect of the ionic strength of the solution, polyelectrolyte concentration, number and polarity of the PE layers on the characteristics of the PEM-modified EIS sensors have been studied by means of capacitance–voltage and constant-capacitance methods. In addition, the thickness, surface morphology, roughness and wettabilityof the PE mono- and multilayers have been characterised by ellipsometry, atomic force microscopy and water contact-angle methods, respectively. To explain potential oscillations on the gate surface and signal behaviour of the capacitive field-effect EIS sensor modified with a PEM, a simplified electrostatic model that takes into account the reduced electrostatic screening of PE charges by mobile ions within the PEM has been proposed and discussed.
Y1  - 2013
U6  - http://dx.doi.org/10.1007/s00216-013-6951-9
SN  - 1432-1130 ; 1618-2642
VL  - 405
IS  - 20
SP  - 6425
EP  - 6436
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Wagner, Holger
A1  - Schöning, Michael Josef
T1  - Functional testing and characterisation of (bio-)chemical sensors on wafer level
JF  - Procedia Chemistry. 1 (2009), H. 1
Y1  - 2009
SN  - 1876-6196
N1  - Proceedings of the Eurosensors XXIII conference ; Eurosensors 23
SP  - 835
EP  - 838
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Wagner, Holger
A1  - Schöning, Michael Josef
T1  - Functional testing and characterisation of (bio-)chemical sensors on wafer level
JF  - Sensors and Actuators B: Chemical. 154 (2011), H. 2
Y1  - 2011
SN  - 1873-3077
N1  - EUROSENSORS XXIII
SP  - 169
EP  - 173
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Wagner, H.
A1  - Schöning, Michael Josef
T1  - Automatisiertes „wafer level“-Testsystem zur Charakterisierung von siliziumbasierten Chemo- und Biosensoren
JF  - Sensoren und Messsysteme 2010 [Elektronische Ressource] : Vorträge der 15. ITG/GMA-Fachtagung vom 18. bis 19. Mai 2010 in Nürnberg / Informationstechnische Gesellschaft im VDE (ITG); VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik (GMA)
Y1  - 2010
SN  - 978-3-8007-3260-9
N1  - Fachtagung Sensoren und Messsysteme 15, 2010, Nürnberg ; Gesellschaft Mess- und Automatisierungstechnik
SP  - 89
EP  - 92
PB  - VDE Verlag
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Thust, M.
A1  - Schöning, Michael Josef
A1  - Müller-Veggian, Mattea
A1  - Kordos, P.
A1  - Lüth, H.
T1  - Cross-sensitivity of a capacitive penicillin sensor combined with a diffusion barrier
JF  - Sensors and Actuators B. 68 (2000), H. 1-3
Y1  - 2000
SN  - 0925-4005
SP  - 260
EP  - 265
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Thust, M.
A1  - Schroth, P.
A1  - Steffen, A.
A1  - Lüth, H.
A1  - Schöning, Michael Josef
T1  - Penicillin detection by means of silicon-based field-effect structures
JF  - Sensors and Materials. 13 (2001), H. 4
Y1  - 2001
SN  - 0392-2510
SP  - 207
EP  - 223
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Schöning, Michael Josef
A1  - Schroth, P.
A1  - Simonis, A.
A1  - Lüth, H.
T1  - An ISFET-based penicillin sensor with high sensitivity, low detection limit and long lifetime
JF  - Sensors and Actuators B. 76 (2001), H. 1-3
Y1  - 2001
SN  - 0925-4005
SP  - 519
EP  - 526
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Schöning, Michael Josef
T1  - Detecting Both Physical and (Bio-)Chemical Parameters by Means of ISFET Devices
JF  - Electroanalysis. 16 (2004), H. 22
Y1  - 2004
SN  - 1040-0397
SP  - 1863
EP  - 1872
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Schöning, Michael Josef
T1  - "High-order” hybrid FET module for (bio)chemical and physical sensing
JF  - Integrated analytical systems / ed. by Salvador Alegret
Y1  - 2003
SN  - 0-444-51037-0
SP  - 587
EP  - 623
PB  - Elsevier
CY  - Amsterdam [u.a.]
ER  -