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- Label-free detection (3)
- capacitive field-effect sensor (3)
- field-effect sensor (3)
- tobacco mosaic virus (TMV) (3)
- Capacitive field-effect sensor (2)
- Field-effect sensor (2)
- LAPS (2)
- gold nanoparticles (2)
- (Bio)degradation (1)
- CNOT (1)
- Capacitive field-effect (1)
- Capacitive model (1)
- C–V method (1)
- DNA biosensor (1)
- DNA hybridization (1)
- Electrolyte–insulator–semiconductor (1)
- Enzyme coverage (1)
- Enzyme logic gate (1)
- Field effect (1)
- Field-effect biosensor (1)
- Gold nanoparticles (1)
- Impedance spectroscopy (1)
- Layer-by-layer adsorption (1)
- Multianalyte detection (1)
- Multicell (1)
- Multiplexing (1)
- Penicillin (1)
- Plant virus (1)
- Poly(allylamine hydrochloride) (1)
- Poly(d,l-lacticacid) (1)
- Real-time monitoring (1)
- TMV adsorption (1)
- Ta₂O₅ gate (1)
- Tobacco mosaic virus (TMV) (1)
- XOR (1)
- Zeta potential (1)
- aminooctanethiol (1)
- atomic layer deposition (1)
- barium strontium titanate (1)
- bi-enzyme biosensor (1)
- biosensor (1)
- capacitive EIS sensor (1)
- capacitive field-effect sensors (1)
- capacitive model (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-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)
- multi-functional material (1)
- multianalyte detection (1)
- nanoparticle coverage (1)
- on-chip integrated addressable EISCAP sensors (1)
- pH sensors (1)
- penicillinase (1)
- plant virus detection (1)
- poly(d, l-lactic acid) (1)
- polystyrene sulfonate (1)
- turnip vein clearing virus (TVCV) (1)
- ultrathin gate insulators (1)
- urease (1)
Utilizing an appropriate enzyme immobilization strategy is crucial for designing enzyme-based biosensors. Plant virus-like particles represent ideal nanoscaffolds for an extremely dense and precise immobilization of enzymes, due to their regular shape, high surface-to-volume ratio and high density of surface binding sites. In the present work, tobacco mosaic virus (TMV) particles were applied for the co-immobilization of penicillinase and urease onto the gate surface of a field-effect electrolyte-insulator-semiconductor capacitor (EISCAP) with a p-Si-SiO₂-Ta₂O₅ layer structure for the sequential detection of penicillin and urea. The TMV-assisted bi-enzyme EISCAP biosensor exhibited a high urea and penicillin sensitivity of 54 and 85 mV/dec, respectively, in the concentration range of 0.1–3 mM. For comparison, the characteristics of single-enzyme EISCAP biosensors modified with TMV particles immobilized with either penicillinase or urease were also investigated. The surface morphology of the TMV-modified Ta₂O₅-gate was analyzed by scanning electron microscopy. Additionally, the bi-enzyme EISCAP was applied to mimic an XOR (Exclusive OR) enzyme logic gate.
An amperometric biosensor using a substrate recycling principle was realized for the detection of low adrenaline concentrations (1 nM) by measurements in phosphate buffer and Ringer’s solution at pH 6.5 and pH 7.4, respectively. In proof-of-concept experiments, a Boolean logic-gate principle has been applied to develop a digital adrenaline biosensor based on an enzyme AND logic gate. The obtained results demonstrate that the developed digital biosensor is capable for a rapid qualitative determination of the presence/absence of adrenaline in a YES/NO statement. Such digital biosensor could be used in clinical diagnostics for the control of a correct insertion of a catheter in the adrenal veins during adrenal venous-sampling procedure.
The LAPS (light-addressable potentiometric sensor) platform is one of the most attractive approaches for chemical and biological sensing with many applications ranging from pH and ion/analyte concentration measurements up to cell metabolism detection and chemical imaging. However, although it is generally accepted that LAPS measurements are spatially resolved, the light-addressability feature of LAPS devices has not been discussed in detail so far. In this work, an extended electrical equivalent-circuit model of the LAPS has been presented, which takes into account possible cross-talk effects due to the capacitive coupling of the non-illuminated region. A shunting effect of the non-illuminated area on the measured photocurrent and addressability of LAPS devices has been studied. It has been shown, that the measured photocurrent will be determined not only by the local interfacial potential in the illuminated region but also by possible interfacial potential changes in the non-illuminated region, yielding cross-talk effects. These findings were supported by the experimental investigations of a penicillin-sensitive multi-spot LAPS and a metal-insulator-semiconductor LAPS as model systems.
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.