Refine
Year of publication
Institute
Language
- English (190) (remove)
Document Type
- Article (160)
- Conference Proceeding (20)
- Part of a Book (9)
- Book (1)
Keywords
- Field-effect sensor (3)
- Label-free detection (3)
- capacitive field-effect sensor (3)
- field-effect sensor (3)
- tobacco mosaic virus (TMV) (3)
- Biosensor (2)
- Capacitive field-effect sensor (2)
- LAPS (2)
- Tobacco mosaic virus (TMV) (2)
- gold nanoparticles (2)
- (Bio)degradation (1)
- Biomolecular logic gate (1)
- Biosensorik (1)
- CNOT (1)
- Capacitive field-effect (1)
- Capacitive model (1)
- Chemical imaging (1)
- Coat protein (1)
- C–V method (1)
- DNA (1)
- DNA biosensor (1)
- DNA hybridization (1)
- Electrolyte–insulator–semiconductor (1)
- Enzyme biosensor (1)
- Enzyme coverage (1)
- Enzyme logic gate (1)
- Enzyme nanocarrier (1)
- Field effect (1)
- Field-effect biosensor (1)
- Field-effect device (1)
- Glucose biosensor (1)
- Glucose oxidase (1)
- Gold nanoparticle (1)
- Gold nanoparticles (1)
- ISFET (1)
- Impedance spectroscopy (1)
- Layer-by-layer adsorption (1)
- Light-addressable potentiometric sensor (1)
- Multianalyte detection (1)
- Multicell (1)
- Multiplexing (1)
- Nanostructuring (1)
- Penicillin (1)
- Plant virus (1)
- Poly(allylamine hydrochloride) (1)
- Poly(d,l-lacticacid) (1)
- Potentiometry (1)
- Real-time monitoring (1)
- TMV adsorption (1)
- Ta₂O₅ gate (1)
- Tobacco mosaic virus (1)
- Wafer (1)
- XOR (1)
- Zeta potential (1)
- acetoin (1)
- aminooctanethiol (1)
- atomic layer deposition (1)
- barium strontium titanate (1)
- bi-enzyme biosensor (1)
- biosensor (1)
- capacitive EIS sensor (1)
- capacitive field-effect biosensor (1)
- capacitive field-effect sensors (1)
- capacitive model (1)
- capillary micro-droplet cell (1)
- contactless conductivity sensor (1)
- control gate (1)
- detection of charged macromolecules (1)
- electrolyte-insulator-semiconductor capacitors (1)
- enzymatic (bio)degradation (1)
- enzyme cascade (1)
- enzyme immobilization (1)
- enzyme-logic gate (1)
- equivalent circuit (1)
- glucose oxidase (GOx) (1)
- high-k material (1)
- horseradish peroxidase (HRP) (1)
- hydrogen peroxide (1)
- impedance spectroscopy (1)
- in-situ monitoring (1)
- lable-free detection (1)
- layer expansion (1)
- multi-functional material (1)
- multianalyte detection (1)
- nanoparticle coverage (1)
- on-chip integrated addressable EISCAP sensors (1)
- pH sensors (1)
- pattern-size reduction (1)
- penicillinase (1)
- plant virus detection (1)
- poly(d, l-lactic acid) (1)
- polystyrene sulfonate (1)
- self-aligned patterning (1)
- turnip vein clearing virus (TVCV) (1)
- ultrathin gate insulators (1)
- urease (1)
- wafer-level testing (1)
Designing novel or optimizing existing biodegradable polymers for biomedical applications requires numerous tests on the effect of substances on the degradation process. In the present work, polymer-modified electrolyte–insulator–semiconductor (PMEIS) sensors have been applied for monitoring an enzymatically catalyzed degradation of polymers for the first time. The thin films of biodegradable polymer poly(d,l-lactic acid) and enzyme lipase were used as a model system. During degradation, the sensors were read-out by means of impedance spectroscopy. In order to interpret the data obtained from impedance measurements, an electrical equivalent circuit model was developed. In addition, morphological investigations of the polymer surface have been performed by means of in situ atomic force microscopy. The sensor signal change, which reflects the progress of degradation, indicates an accelerated degradation in the presence of the enzyme compared to hydrolysis in neutral pH buffer media. The degradation rate increases with increasing enzyme concentration. The obtained results demonstrate the potential of PMEIS sensors as a very promising tool for in situ and real-time monitoring of degradation of polymers.
A microfluidic chip integrating amperometric enzyme sensors for the detection of glucose, glutamate and glutamine in cell-culture fermentation processes has been developed. The enzymes glucose oxidase, glutamate oxidase and glutaminase were immobilized by means of cross-linking with glutaraldehyde on platinum thin-film electrodes integrated within a microfluidic channel. The biosensor chip was coupled to a flow-injection analysis system for electrochemical characterization of the sensors. The sensors have been characterized in terms of sensitivity, linear working range and detection limit. The sensitivity evaluated from the respective peak areas was 1.47, 3.68 and 0.28 μAs/mM for the glucose, glutamate and glutamine sensor, respectively. The calibration curves were linear up to a concentration of 20 mM glucose and glutamine and up to 10 mM for glutamate. The lower detection limit amounted to be 0.05 mM for the glucose and glutamate sensor, respectively, and 0.1 mM for the glutamine sensor. Experiments in cell-culture medium have demonstrated a good correlation between the glutamate, glutamine and glucose concentrations measured with the chip-based biosensors in a differential-mode and the commercially available instrumentation. The obtained results demonstrate the feasibility of the realized microfluidic biosensor chip for monitoring of bioprocesses.
Real-time and reliable monitoring of the biogas process is crucial for a stable and efficient operation of biogas production in order to avoid digester breakdowns. The concentration of dissolved hydrogen (H₂) represents one of the key parameters for biogas process control. In this work, a one-chip integrated combined amperometric/field-effect sensor for monitoring the dissolved H₂ concentration has been developed for biogas applications. The combination of two different transducer principles might allow a more accurate and reliable measurement of dissolved H₂ as an early warning indicator of digester failures. The feasibility of the approach has been demonstrated by simultaneous amperometric/field-effect measurements of dissolved H₂ concentrations in electrolyte solutions. Both, the amperometric and the field-effect transducer show a linear response behaviour in the H₂ concentration range from 0.1 to 3% (v/v) with a slope of 198.4 ± 13.7 nA/% (v/v) and 14.9 ± 0.5 mV/% (v/v), respectively.
It is well known that the degradation environment can strongly influence the biodegradability and kinetics of biodegradation processes of polymers. Therefore, besides the monitoring of the degradation process, it is also necessary to control the medium in which the degradation takes place. In this work, a micromachined multi-parameter sensor chip for the control of the polymer-degradation medium has been developed. The chip combines a capacitive field-effect pH sensor, a four-electrode electrolyte-conductivity sensor and a thin-film Pt-temperature sensor. The results of characterization of individual sensors are presented. In addition, the multi-parameter sensor chip together with an impedimetric polymer-degradation sensor was simultaneously characterized in degradation solutions with different pH and electrolyte conductivity. The obtained results demonstrate the feasibility of the multi-parameter sensor chip for the control of the polymer-degradation medium.
The conjunction of (bio-)chemical recognition elements with nanoscale biological building blocks such as virus particles is considered as a very promising strategy for the creation of biohybrids opening novel opportunities for label-free biosensing. This work presents a new approach for the development of biosensors using tobacco mosaic virus (TMV) nanotubes or coat proteins (CPs) as enzyme nanocarriers. Sensor chips combining an array of Pt electrodes loaded with glucose oxidase (GOD)-modified TMV nanotubes or CP aggregates were used for amperometric detection of glucose as a model system for the first time. The presence of TMV nanotubes or CPs on the sensor surface allows binding of a high amount of precisely positioned enzymes without substantial loss of their activity, and may also ensure accessibility of their active centers for analyte molecules. Specific and efficient immobilization of streptavidin-conjugated GOD ([SA]-GOD) complexes on biotinylated TMV nanotubes or CPs was achieved via bioaffinity binding. These layouts were tested in parallel with glucose sensors with adsorptively immobilized [SA]-GOD, as well as [SA]-GOD crosslinked with glutardialdehyde, and came out to exhibit superior sensor performance. The achieved results underline a great potential of an integration of virus/biomolecule hybrids with electronic transducers for future applications in biosensorics and biochips.
Planar and three-dimensional (3D) interdigitated electrodes (IDE) with electrode digits separated by an insulating barrier of different heights were electrochemically characterized and compared in terms of their sensing properties. Due to the impact of the surface resistance, both types of IDE structures display a non-linear behavior in low-ionic strength solutions. The experimental data were fitted to an electrical equivalent circuit and interpreted taking into account the surface-charge-governed properties. The effect of a charged polyelectrolyte layer electrostatically assembled onto the sensor surface on the surface resistance in solutions with different KCl concentration is studied. In case of the same electrode footprint, 3D-IDEs show a larger cell constant and a higher sensitivity to molecular adsorption than that of planar IDEs. The obtained results demonstrate the potential of 3D-IDEs as a new transducer structure for a direct label-free sensing of charged molecules.
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.
An enzyme system organized in a flow device was used to mimic a reversible Controlled NOT (CNOT) gate with two input and two output signals. Reversible conversion of NAD⁺ and NADH cofactors was used to perform a XOR logic operation, while biocatalytic hydrolysis of p-nitrophenyl phosphate resulted in an Identity operation working in parallel. The first biomolecular realization of a CNOT gate is promising for integration into complex biomolecular networks and future biosensor/biomedical applications.