Refine
Year of publication
Document Type
- Article (87)
- Conference Proceeding (9)
- Part of a Book (2)
Has Fulltext
- no (98) (remove)
Keywords
- Light-addressable potentiometric sensor (3)
- LAPS (2)
- Chemical images (1)
- Chemical imaging (1)
- Chemical imaging sensor (1)
- Chemical sensor (1)
- EIS capacitive sensor (1)
- Field-effect device (1)
- Light-addressable Potentiometric Sensor (1)
- MOS (1)
- Negative impedance convertor (1)
- Organic light-emitting diode display (1)
- Potentiometry (1)
- Resonance-mode measurement (1)
- artificial olfactory image (1)
- catalytic metal (1)
- chemical sensor (1)
- electronic nose (1)
- field-effect structure (1)
- gas sensor (1)
Institute
- Fachbereich Medizintechnik und Technomathematik (98) (remove)
A capacitive electrolyte-insulator-semiconductor (EIS) field-effect biosensor for acetoin detection has been presented for the first time. The EIS sensor consists of a layer structure of Al/p-Si/SiO₂/Ta₂O₅/enzyme acetoin reductase. The enzyme, also referred to as butane-2,3-diol dehydrogenase from B. clausii DSM 8716T, has been recently characterized. The enzyme catalyzes the (R)-specific reduction of racemic acetoin to (R,R)- and meso-butane-2,3-diol, respectively. Two different enzyme immobilization strategies (cross-linking by using glutaraldehyde and adsorption) have been studied. Typical biosensor parameters such as optimal pH working range, sensitivity, hysteresis, linear concentration range and long-term stability have been examined by means of constant-capacitance (ConCap) mode measurements. Furthermore, preliminary experiments have been successfully carried out for the detection of acetoin in diluted white wine samples.
The chemical imaging sensor is a semiconductor-based chemical sensor capable of visualizing pH and ion distributions. The spatial resolution depends on the lateral diffusion of photocarriers generated by illumination of the semiconductor substrate. In this study, two types of optical setups, one based on a bundle of optical fibers and the other based on a binocular tube head, were developed to project a hybrid illumination of a modulated light beam and a ring-shaped constant illumination onto the sensor plate. An improved spatial resolution was realized by the ring-shaped constant illumination, which suppressed lateral diffusion of photocarriers by enhanced recombination due to the increased carrier concentration.
Visualization of the recovery process of defects in a cultured cell layer by chemical imaging sensor
(2016)
The chemical imaging sensor is a field-effect sensor which is able to visualize both the distribution of ions (in LAPS mode) and the distribution of impedance (in SPIM mode) in the sample. In this study, a novel cell assay is proposed, in which the chemical imaging sensor operated in SPIM mode is applied to monitor the recovery of defects in a cell layer brought into proximity of the sensing surface. A reduced impedance at a defect formed artificially in a cell layer was successfully visualized in a photocurrent image. The cell layer was cultured over two weeks, during which the temporal change of the photocurrent distribution corresponding to the recovery of the defect was observed.