Refine
Year of publication
Document Type
- Article (462)
- Conference Proceeding (50)
- Part of a Book (9)
- Book (2)
- Other (2)
- Report (1)
Language
- English (475)
- German (50)
- Multiple languages (1)
Keywords
- Biosensor (5)
- Graduiertentagung (4)
- LAPS (3)
- Label-free detection (3)
- Light-addressable potentiometric sensor (3)
- biosensors (3)
- capacitive field-effect sensor (3)
- field-effect sensor (3)
- hydrogen peroxide (3)
- tobacco mosaic virus (TMV) (3)
- Bacillus atrophaeus (2)
- Calorimetric gas sensor (2)
- Capacitive field-effect sensor (2)
- Hydrogen peroxide (2)
- Raman spectroscopy (2)
- Tobacco mosaic virus (TMV) (2)
- acetoin (2)
- capacitive field-effect sensors (2)
- gold nanoparticles (2)
- light-addressable potentiometric sensor (2)
- penicillinase (2)
- sterilisation (2)
- (Bio)degradation (1)
- Aachen / Fachhochschule Aachen (1)
- Bacillus atrophaeus spores (1)
- Bio-Sensors (1)
- Bioabsorbable (1)
- Biosensorik (1)
- CNOT (1)
- Capacitive field-effect (1)
- Capacitive model (1)
- Chemical images (1)
- Chemical imaging (1)
- Chemical imaging sensor (1)
- Chemical sensor (1)
- Coat protein (1)
- C–V method (1)
- DNA biosensor (1)
- DPA (dipicolinic acid) (1)
- Dehydrogenase (1)
- Diaphorase (1)
- EIS capacitive sensor (1)
- Electrolyte–insulator–semiconductor (1)
- Enzymatic biosensor (1)
- Enzyme coverage (1)
- Enzyme logic gate (1)
- Enzyme nanocarrier (1)
- Field effect (1)
- Field-effect biosensor (1)
- Field-effect device (1)
- Field-effect sensor (1)
- Gas sensor (1)
- Glucose biosensor (1)
- Glucose oxidase (1)
- Gold nanoparticles (1)
- Graduate symposium (1)
- Graduierter (1)
- Heavy metal detection (1)
- ISFET (1)
- Impedance spectroscopy (1)
- Layer-by-layer adsorption (1)
- LbL films (1)
- MOS (1)
- Multi-sensor system (1)
- Multianalyte detection (1)
- Multicell (1)
- Multiplexing (1)
- Nano Materials (1)
- Nanomaterial (1)
- Nanostructuring (1)
- Nanotechnologie (1)
- Negative impedance convertor (1)
- O2 plasma (1)
- Organic light-emitting diode display (1)
- Penicillin (1)
- Plant virus (1)
- Poly(allylamine hydrochloride) (1)
- Poly(d,l-lacticacid) (1)
- Polyimide (1)
- Polylactide acid (1)
- Potentiometry (1)
- Promotionsstudium (1)
- Real-time monitoring (1)
- Resistive temperature detector (1)
- Resonance-mode measurement (1)
- Silk fibroin (1)
- Simultaneous determination (1)
- Sn₃O₄ (1)
- Sterilisation process (1)
- TMV adsorption (1)
- Ta₂O₅ gate (1)
- Tobacco mosaic virus (1)
- Wafer (1)
- XOR (1)
- Zeta potential (1)
- acetoin reductase (1)
- actuator-sensor system (1)
- alcoholic beverages (1)
- aminooctanethiol (1)
- amperometric biosensors (1)
- annealing (1)
- artificial olfactory image (1)
- aseptic parameters (1)
- atomic layer deposition (1)
- bi-enzyme biosensor (1)
- bioburdens (1)
- biocompatible (1)
- biocompatible materials (1)
- biodegradabl (1)
- biodegradable electronic devices (1)
- biosensor (1)
- calorimetric gas sensor (1)
- calorimetric gas sensor;hydrogen peroxide;wireless sensor system (1)
- capacitive EIS sensor (1)
- capacitive electrolyte–insulator–semiconductor sensors (1)
- capacitive field-effect biosensor (1)
- capacitive model (1)
- capillary micro-droplet cell (1)
- carbon electrodes (1)
- catalytic decomposition (1)
- catalytic metal (1)
- chemical sensor (1)
- control gate (1)
- detection of charged macromolecules (1)
- electrolyte-insulator semiconductor sensor (EIS) (1)
- electrolyte-insulator-semiconductor capacitors (1)
- electronic nose (1)
- encapsulation materials (1)
- endospores (1)
- enzymatic biosensor (1)
- enzyme cascade (1)
- enzyme immobilization (1)
- enzyme kinetics (1)
- enzyme-logic gate (1)
- equivalent circuit (1)
- fibroin (1)
- field-effect structure (1)
- gas sensor (1)
- gaseous hydrogen peroxide (1)
- glucose (1)
- glucose oxidase (GOx) (1)
- graphene oxide (1)
- heavy metals (1)
- horseradish peroxidase (HRP) (1)
- hydroxylation (1)
- immobilization (1)
- layer expansion (1)
- layer-by-layer technique (1)
- light-addressable electrode (1)
- light-addressing technologies (1)
- metal-oxide-semiconductor structure (1)
- microfluidics (1)
- multi-sensing platform (1)
- multianalyte detection (1)
- nanobelts (1)
- nanomaterials (1)
- nanoparticle coverage (1)
- on-chip integrated addressable EISCAP sensors (1)
- optical sensor setup (1)
- optical spore trapping (1)
- optical trapping (1)
- organic PVC membranes (1)
- organosilanes (1)
- pH sensors (1)
- pattern-size reduction (1)
- penicillin (1)
- photoelectrochemistry (1)
- plant virus detection (1)
- plug-based microfluidic device (1)
- polyaniline (1)
- polystyrene sulfonate (1)
- scanned light pulse technique (1)
- self-aligned patterning (1)
- silanization (1)
- spore kill rate (1)
- sterility (1)
- sterility tests (1)
- sterilization (1)
- sterilization conditions (1)
- sterilization efficacy (1)
- sterilization methods (1)
- surface functionalization (1)
- temperature (1)
- thin-film microsensors (1)
- titanium dioxide photoanode (1)
- turnip vein clearing virus (TVCV) (1)
- ultrathin gate insulators (1)
- urease (1)
- validation methods (1)
- visualization (1)
- wafer-level testing (1)
Institute
- INB - Institut für Nano- und Biotechnologien (526) (remove)
In this work, a multi-sensor chip for the investigation of the sensing properties of different types of metal oxides towards hydrogen peroxide in the ppm range is presented. The fabrication process and physical characterization of the multi-sensor chip are described. Pure SnO2 and WO3 as well as Pd- and Pt-doped SnO2 films are characterized in terms of their sensitivity to H2O2. The sensing films have been prepared by drop-coating of water-dispensed nano-powders. A physical characterization, including scanning electron microscopy and X-ray diffraction analysis of the deposited metal-oxide films, was done. From the measurements in hydrogen peroxide atmosphere, it could be shown, that all of the tested metal oxide films are suitable for the detection of H2O2 in the ppm range. The highest sensitivity and reproducibility was achieved using Pt-doped SnO2.
Calibration plot of a SnO2, WO3, Pt-, and Pd-doped SnO2 gas sensor for H2O2 concentrations in the ppm range.
Algal polysaccharides (extracellular polysaccharides) and carbon nanotubes (CNTs) were adsorbed on dioctadecyldimethylammonium bromide Langmuir monolayers to serve as a matrix for the incorporation of urease. The physicochemical properties of the supramolecular system as a monolayer at the air–water interface were investigated by surface pressure–area isotherms, surface potential–area isotherms, interfacial shear rheology, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to hydrophilic solid supports, quartz, mica, or capacitive electrolyte–insulator–semiconductor (EIS) devices, through the Langmuir–Blodgett (LB) technique, forming mixed films, which were investigated by quartz crystal microbalance, fluorescence spectroscopy, and field emission gun scanning electron microscopy. The enzyme activity was studied with UV–vis spectroscopy, and the feasibility of the thin film as a urea sensor was essayed in an EIS sensor device. The presence of CNT in the enzyme–lipid LB film not only tuned the catalytic activity of urease but also helped to conserve its enzyme activity. Viability as a urease sensor was demonstrated with capacitance–voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results are related to the synergism between the compounds on the active layer, leading to a surface morphology that allowed fast analyte diffusion owing to an adequate molecular accommodation, which also preserved the urease activity. This work demonstrates the feasibility of employing LB films composed of lipids, CNT, algal polysaccharides, and enzymes as EIS devices for biosensing applications.
Monitoring of organic acids (OA) and volatile fatty acids (VFA) is crucial for the control of anaerobic digestion. In case of unstable process conditions, an accumulation of these intermediates occurs. In the present work, two different enzyme-based biosensor arrays are combined and presented for facile electrochemical determination of several process-relevant analytes. Each biosensor utilizes a platinum sensor chip (14 × 14 mm²) with five individual working electrodes. The OA biosensor enables simultaneous measurement of ethanol, formate, d- and l-lactate, based on a bi-enzymatic detection principle. The second VFA biosensor provides an amperometric platform for quantification of acetate and propionate, mediated by oxidation of hydrogen peroxide. The cross-sensitivity of both biosensors toward potential interferents, typically present in fermentation samples, was investigated. The potential for practical application in complex media was successfully demonstrated in spiked sludge samples collected from three different biogas plants. Thereby, the results obtained by both of the biosensors were in good agreement to the applied reference measurements by photometry and gas chromatography, respectively. The proposed hybrid biosensor system was also used for long-term monitoring of a lab-scale biogas reactor (0.01 m³) for a period of 2 months. In combination with typically monitored parameters, such as gas quality, pH and FOS/TAC (volatile organic acids/total anorganic carbonate), the amperometric measurements of OA and VFA concentration could enhance the understanding of ongoing fermentation processes.
Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD+) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM−1 (L-malate biosensor) and 0.4 μA mM−1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0–10.0 mM with a sensitivity of 0.09 μA mM−1. The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates.
In this paper, carbon nanotubes (CNTs) were incorporated in penicillinase-phospholipid Langmuir and Langmuir–Blodgett (LB) films to enhance the enzyme catalytic properties. Adsorption of the penicillinase and CNTs at dimyristoylphosphatidic acid (DMPA) monolayers at the air–water interface was investigated by surface pressure–area isotherms, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to solid supports through the LB technique, forming mixed DMPA-CNTs-PEN films, which were investigated by quartz crystal microbalance, vibrational spectroscopy, and atomic force microscopy. Enzyme activity was studied with UV–vis spectroscopy and the feasibility of the supramolecular device nanostructured as ultrathin films were essayed in a capacitive electrolyte–insulator–semiconductor (EIS) sensor device. The presence of CNTs in the enzyme–lipid LB film not only tuned the catalytic activity of penicillinase but also helped conserve its enzyme activity after weeks, showing increased values of activity. Viability as penicillin sensor was demonstrated with capacitance/voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results may be related not only to the nanostructured system provided by the film, but also to the synergism between the compounds on the active layer, leading to a surface morphology that allowed a fast analyte diffusion because of an adequate molecular accommodation, which also preserved the penicillinase activity. This work therefore demonstrates the feasibility of employing LB films composed of lipids, CNTs, and enzymes as EIS devices for biosensing applications.
Characterising an insect antenna as a receptor for a biosensor by means of impedance spectroscopy
(2001)
Doktoranden der FH Aachen stellen ihre wissenschaftlichen Arbeiten aus verschiedenen Fachdisziplinen vor.