TY  - JOUR
A1  - Huck, Christina
A1  - Poghossian, Arshak
A1  - Bäcker, Matthias
A1  - Reisert, Steffen
A1  - Kramer, Friederike
A1  - Begoyan, Vardges K.
A1  - Buniatyan, Vahe V.
A1  - Schöning, Michael Josef
T1  - Multi-parameter sensing using high-k oxide of barium strontium titanate
JF  - Physica status solidi (a)
N2  - High-k perovskite oxide of barium strontium titanate (BST) represents a very attractive multi-functional transducer material for the development of (bio-)chemical sensors. In this work, a Si-based sensor chip containing Pt interdigitated electrodes covered with a thin BST layer (485 nm) has been developed for multi-parameter chemical sensing. The chip has been applied for the contactless measurement of the electrolyte conductivity, the detection of adsorbed charged macromolecules (positively charged polyelectrolytes of polyethylenimine) and the concentration of hydrogen peroxide (H2O2) vapor. The experimental results of functional testing of individual sensors are presented. The mechanism of the BST sensitivity to charged polyelectrolytes and H2O2 vapor has been proposed and discussed.
Y1  - 2015
U6  - http://dx.doi.org/10.1002/pssa.201431911
SN  - 1862-6319
VL  - 212
IS  - 6
SP  - 1259
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Bronder, Thomas
A1  - Poghossian, Arshak
A1  - Scheja, Sabrina
A1  - Wu, Chunsheng
A1  - Keusgen, Michael
A1  - Mewes, Dieter
A1  - Schöning, Michael Josef
T1  - DNA Immobilization and Hybridization Detection by the Intrinsic Molecular Charge Using Capacitive Field-Effect Sensors Modified with a Charged Weak Polyelectrolyte Layer
JF  - Applied Materials & Interfaces
N2  - Miniaturized setup, compatibility with advanced micro- and nanotechnologies, and ability to detect biomolecules by their intrinsic molecular charge favor the semiconductor field-effect platform as one of the most attractive approaches for the development of label-free DNA chips. In this work, a capacitive field-effect EIS (electrolyte–insulator–semiconductor) sensor covered with a layer-by-layer prepared, positively charged weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)) was used for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization. The negatively charged probe single-stranded DNA (ssDNA) molecules were electrostatically adsorbed onto the positively charged PAH layer, resulting in a preferentially flat orientation of the ssDNA molecules within the Debye length, thus yielding a reduced charge-screening effect and a higher sensor signal. Each sensor-surface modification step (PAH adsorption, probe ssDNA immobilization, hybridization with complementary target DNA (cDNA), reducing an unspecific adsorption by a blocking agent, incubation with noncomplementary DNA (ncDNA) solution) was monitored by means of capacitance–voltage and constant-capacitance measurements. In addition, the surface morphology of the PAH layer was studied by atomic force microscopy and contact-angle measurements. High hybridization signals of 34 and 43 mV were recorded in low-ionic strength solutions of 10 and 1 mM, respectively. In contrast, a small signal of 4 mV was recorded in the case of unspecific adsorption of fully mismatched ncDNA. The density of probe ssDNA and dsDNA molecules as well as the hybridization efficiency was estimated using the experimentally measured DNA immobilization and hybridization signals and a simplified double-layer capacitor model. The results of field-effect experiments were supported by fluorescence measurements, verifying the DNA-immobilization and hybridization event.
Y1  - 2015
U6  - http://dx.doi.org/10.1021/acsami.5b05146
VL  - 36
IS  - 7
SP  - 20068
EP  - 20075
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Bronder, Thomas
A1  - Poghossian, Arshak
A1  - Scheja, S.
A1  - Wu, Chunsheng
A1  - Keusgen, M.
A1  - Schöning, Michael Josef
T1  - Electrostatic Detection of Unlabelled Single- and Double-stranded DNA Using Capacitive Field-effect Devices Functionalized with a Positively Charged Polyelectrolyte Layer
JF  - Procedia Engineering
N2  - Capacitive field-effect electrolyte-insulator-semiconductor sensors consisting of an Al-p-Si-SiO2 structure have been used for the electrical detection of unlabelled single- and double-stranded DNA (dsDNA) molecules by their intrinsic charge. A simple functionalization protocol based on the layer-by-layer (LbL) technique was used to prepare a weak polyelectrolyte/probe-DNA bilayer, followed by the hybridization with complementary target DNA molecules. Due to the flat orientation of the LbL-adsorbed DNA molecules, a high sensor signal has been achieved. In addition, direct label-free detection of in-solution hybridized dsDNA molecules has been studied.
Y1  - 2015
U6  - http://dx.doi.org/10.1016/j.proeng.2015.08.710
SN  - 1877-7058
N1  - Eurosensors 2015
VL  - 120
SP  - 544
EP  - 547
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Beging, Stefan
A1  - Leinhos, Marcel
A1  - Jablonski, Melanie
A1  - Poghossian, Arshak
A1  - Schöning, Michael Josef
T1  - Studying the spatially resolved immobilisation of enzymes on a capacitive field-effect structure by means of nano-spotting
JF  - Physica status solidi (a)
Y1  - 2015
U6  - http://dx.doi.org/10.1002/pssa.201431891
SN  - 1862-6319
VL  - 212
IS  - 6
SP  - 1353
EP  - 1358
PB  - Wiley
CY  - Weinheim
ER  -