Refine
Year of publication
Document Type
- Article (540)
- Conference Proceeding (52)
- Part of a Book (9)
- Doctoral Thesis (4)
- Book (3)
- Other (2)
- Report (2)
- Patent (1)
Language
- English (555)
- German (57)
- Multiple languages (1)
Keywords
- Biosensor (6)
- Graduiertentagung (4)
- biosensors (4)
- frequency mixing magnetic detection (4)
- LAPS (3)
- Label-free detection (3)
- Light-addressable potentiometric sensor (3)
- capacitive field-effect sensor (3)
- field-effect sensor (3)
- hydrogen peroxide (3)
- magnetic nanoparticles (3)
- tobacco mosaic virus (TMV) (3)
- Acyl-amino acids (2)
- Aminoacylase (2)
- Bacillaceae (2)
- Bacillus atrophaeus (2)
- Biotechnological application (2)
- Calorimetric gas sensor (2)
- Capacitive field-effect sensor (2)
- Hydrogen peroxide (2)
- Raman spectroscopy (2)
- Subtilases (2)
- Subtilisin (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)
- Acylation (1)
- Alginate beads (1)
- Alkalihalobacillus okhensis (1)
- Bacillus atrophaeus spores (1)
- Bio-Sensors (1)
- Bioabsorbable (1)
- Biocatalysis (1)
- Biosensorik (1)
- Biosurfactants (1)
- Broad pH spectrum (1)
- CNOT (1)
- CRISPR/Cas9 (1)
- Capacitive field-effect (1)
- Capacitive model (1)
- Chaperone (1)
- Chaperone co-expression (1)
- Chemical images (1)
- Chemical imaging (1)
- Chemical imaging sensor (1)
- Chemical sensor (1)
- Choleratoxin B (1)
- Coat protein (1)
- C–V method (1)
- DNA biosensor (1)
- DPA (dipicolinic acid) (1)
- Dehydrogenase (1)
- Detergent protease (1)
- Diaphorase (1)
- EIS capacitive sensor (1)
- Electrolyte–insulator–semiconductor (1)
- Enzymatic biosensor (1)
- Enzyme coverage (1)
- Enzyme logic gate (1)
- Enzyme nanocarrier (1)
- Extracellular enzymes (1)
- Field effect (1)
- Field-effect biosensor (1)
- Field-effect device (1)
- Field-effect sensor (1)
- GaAs hot electron injector (1)
- Gas sensor (1)
- Glucose biosensor (1)
- Glucose oxidase (1)
- Gold nanoparticles (1)
- Graduate symposium (1)
- Graduierter (1)
- Gunn diode (1)
- Halotolerant protease (1)
- Heavy metal detection (1)
- Hypersecretion (1)
- ISFET (1)
- Impedance spectroscopy (1)
- Inclusion bodies (1)
- Lab-on-Chip (1)
- Layer-by-layer adsorption (1)
- LbL films (1)
- MOS (1)
- Marker-free mutagenesis (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)
- Stenotrophomonas maltophilia (1)
- Sterilisation process (1)
- Streptomyces griseus (1)
- Streptomyces lividans (1)
- TMV adsorption (1)
- Ta₂O₅ gate (1)
- Tobacco mosaic virus (1)
- Trinkwassersicherheit (1)
- Uracil-phosphoribosyltransferase (1)
- Vibrio natriegens (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)
- aspergillus (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)
- cholera toxin B (1)
- colorization (1)
- control gate (1)
- coupled Néel–Brownian relaxation dynamics (1)
- detection of charged macromolecules (1)
- detergent protease (1)
- drinking water safety (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)
- filamentous fungi (1)
- frequency mixing (1)
- gas sensor (1)
- gaseous hydrogen peroxide (1)
- genome engineering (1)
- glucose (1)
- glucose oxidase (GOx) (1)
- graphene oxide (1)
- halotolerant protease (1)
- heavy metals (1)
- high-alkaline subtilisin (1)
- horseradish peroxidase (HRP) (1)
- hydroxylation (1)
- immobilization (1)
- key performance indicators (1)
- layer expansion (1)
- layer-by-layer technique (1)
- light-addressable electrode (1)
- light-addressing technologies (1)
- magnetic actuation (1)
- magnetic beads (1)
- magnetic biosensing (1)
- magnetic frequency mixing technique (1)
- magnetic relaxation (1)
- magnetic sandwich immunoassay (1)
- magnetic sensing (1)
- magnetic sensors (1)
- magnetic separation (1)
- magnetic tweezers (1)
- magnetophoretic velocity (1)
- metal-oxide-semiconductor structure (1)
- microfluidics (1)
- micromagnetic simulation (1)
- microwave generation (1)
- multi-sensing platform (1)
- multianalyte detection (1)
- multiparametric immunoassays (1)
- multiplex 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)
- oxidative stable protease (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)
- recombinant expression (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)
- superparamagnetic bead (1)
- superparamagnetic nanoparticles (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)
- α-aminoacylase (1)
- ε-lysine acylase (1)
Institute
- INB - Institut für Nano- und Biotechnologien (613) (remove)
The chemical imaging sensor is a device to visualize the spatial distribution of chemical species based on the principle of LAPS (light-addressable potentiometric sensor), which is a field-effect chemical sensor based on semiconductor. In this study, the chemical imaging sensor has been applied to investigate the ion profile of laminar flows in a microfluidic channel. The chemical images (pH maps) were collected in a Y-shaped microfluidic channel while injecting HCl and NaCl solutions into two branches. From the chemical images, it was clearly observed that the injected solutions formed laminar flows in the channel. In addition, ion diffusion across the laminar flows was observed, and the diffusion coefficient could be derived by fitting the pH profiles to the Fick's equation.
Living cells are complex biological systems transforming metabolites taken up from the surrounding medium. Monitoring the responses of such cells to certain substrate concentrations is a challenging task and offers possibilities to gain insight into the vitality of a community influenced by the growth environment. Cell-based sensors represent a promising platform for monitoring the metabolic activity and thus, the “welfare” of relevant organisms. In the present study, metabolic responses of the model bacterium Escherichia coli in suspension, layered onto a capacitive field-effect structure, were examined to pulses of glucose in the concentration range between 0.05 and 2 mM. It was found that acidification of the surrounding medium takes place immediately after glucose addition and follows Michaelis–Menten kinetic behavior as a function of the glucose concentration. In future, the presented setup can, therefore, be used to study substrate specificities on the enzymatic level and may as well be used to perform investigations of more complex metabolic responses. Conclusions and perspectives highlighting this system are discussed.
Impedance spectroscopy: A tool for real-time in situ monitoring of the degradation of biopolymers
(2013)
Investigation of the degradation kinetics of biodegradable polymers is essential for the development of implantable biomedical devices with predicted biodegradability. In this work, an impedimetric sensor has been applied for real-time and in situ monitoring of degradation processes of biopolymers. The sensor consists of two platinum thin-film electrodes covered by a polymer film to be studied. The benchmark biomedical polymer poly(D,L-lactic acid) (PDLLA) was used as a model system. PDLLA films were deposited on the sensor structure from a polymer solution by using the spin-coating method. The degradation kinetics of PDLLA films have been studied in alkaline solutions of pH 9 and 12 by means of an impedance spectroscopy (IS) method. Any changes in a polymer capacitance/resistance induced by water uptake and/or polymer degradation will modulate the global impedance of the polymer-covered sensor that can be used as an indicator of the polymer degradation. The degradation rate can be evaluated from the time-dependent impedance spectra. As expected, a faster degradation has been observed for PDLLA films exposed to pH 12 solution.
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.
Light-addressable potentiometric sensors (LAPS) are semiconductor-based potentiometric sensors, with the advantage to detect the concentration of a chemical species in a liquid solution above the sensor surface in a spatially resolved manner. The addressing is achieved by a modulated and focused light source illuminating the semiconductor and generating a concentration-depending photocurrent. This work introduces a LAPS set-up that is able to monitor the electrical impedance in addition to the photocurrent. The impedance spectra of a LAPS structure, with and without illumination, as well as the frequency behaviour of the LAPS measurement are investigated. The measurements are supported by electrical equivalent circuits to explain the impedance and the LAPS-frequency behaviour. The work investigates the influence of different parameters on the frequency behaviour of the LAPS. Furthermore, the phase shift of the photocurrent, the influence of the surface potential as well as the changes of the sensor impedance will be discussed.
The chemical imaging sensor is a semiconductor-based chemical sensor that can visualize the spatial distribution of specific ions on the sensing surface. The conventional chemical imaging system based on the light-addressable potentiometric sensor (LAPS), however, required a long time to obtain a chemical image, due to the slow mechanical scan of a single light beam. For high-speed imaging, a plurality of light beams modulated at different frequencies can be employed to measure the ion concentrations simultaneously at different locations on the sensor plate by frequency division multiplex (FDM). However, the conventional measurement geometry of back-side illumination limited the bandwidth of the modulation frequency required for FDM measurement, because of the low-pass filtering characteristics of carrier diffusion in the Si substrate. In this study, a high-speed chemical imaging system based on front-side-illuminated LAPS was developed, which achieved high-speed spatiotemporal recording of pH change at a rate of 70 frames per second.