Flow-through biosensor

Bioluminescent reactions have been thoroughly investigated with a view to designing integrated flow-through biosensors using firefly and bacterial... 

Figure 3.10 — Flow manifolds for implementation of flow-through biosensors. (A) Flow injection merging-zones manifold for the bioluminescence detennination of ATP. ATP standards (30 fiL) and luciferin (30 fiL) are injected into the buffered carrier streams, each pumped at 0.7 mL/min and synchronously merged 12.5 cm downstream. Distance from merging point to immobilized enzyme coil, 2.2 cm. (Reproduced from [59] with permission of Elsevier Science Publishers). (B) Completely continuous flow manifold for the determination of NADH. (Reproduced from [71] with permission of the Royal Society of Chemistry). (C) Segmented-flow manifold for the determination of L-(+)-lactate. (Reproduced from [65] with permission of Marcel Dekker, Inc.). (D) Single-channel flow injection manifold with immobilized reagent for the detennination of glucose. (Reproduced from [77] with permission of Elsevier Science Publishers).

Most of the amperometric flow-through biosensors based on commercially available enzymes are employed to measure consumed or released oxygen by using a Clark electrode or a solid-state electrode to monitor the hydrogen peroxide formed or an enzymatically reduced acceptor. 

Groom and Luong [103] designed a flow-through biosensor for cyanide consisting of a column packed with rhodanase immobilized on a preactivated nylon membrane attached to the surface of a hydrogen peroxide... 

Figure 5.5 — Flow-through biosensor for the determination of L-glutamate. (A) Flow injection manifold. (B) Sensing microzone of the probe sensor (optrode), incorporated in the flow-cell (FTC). P pump IV injection valve MC mixing chamber AD air damper BFB bifurcated fibre bimdle LS light source PMT photomultiplier R recorder GLU L-glutamate 0-Glu 2-oxoglutarate E enzyme layer I optical insulator S sensing layer PS polyester support. For details, see text. (Adapted from [6] with permission of Elsevier Science Publishers).

Figure 5.11 — Diagram of a generic electrochemical flow-through biosensor using a permselective film coating the surface of the en2yme electrode. RE reference electrode AE auxiliary electrode W waste.

Ruzicka ei al. [57,58] developed some peculiar reflectance flow-through biosensors based on a sensing microzone accommodating an enzyme and an acid-base indicator (both in immobilized form) where spacial and temporal resolution of the biochemical and chemical reaction or the reversible separation of hydrogen ions was therefore impossible. The pH sensors developed by these authors (see Section 3.5.1.1) can be regarded as precedents for these reflectance sensors. The sensing approach used relies on... 

The drawback of this approach turned out to be samples of submicrolitre level, which necessitated the development of a dedicated small measuring device with a very low dead volume. A portable lightweight apparatus, consisting in a miniaturized flow-through biosensor connected to a microdialysis probe at one side, and to a semi-vacuum pulse-free pump at the other was then built. A portable potentiostat equipped for data collection and storage was used to handle data. 

CHEMILUMINESCENCE FLOW-THROUGH BIOSENSOR FOR HYDROGEN PEROXIDE BASED ON ENHANCED HRP ACTIVITY BY GOLD NANOPARTICLES... 

Fig.l. Schematic diagram of the flow-through biosensor for the determination of H202 (a) sample (b) luminol (c) buffer solution P peristaltic pump V injection valve F flow cell immobilized HRP and Au nanoparticles D detector PC ... 

Chemiluminescence Flow-Through Biosensor for Hydrogen Pyroxide 219... 

The immobilization can be performed with a modality different from that of the reactor filled with the immobilized enzyme. The spectrophotometric control of hemodialysis treatment is based on an optical flow-through biosensor based on Prussian Blue film with chemically linked urease forming a monomo-lecular layer of the enzyme. This pH-enzyme opt-rode-FIA system has been used for the selective determination of postdialyzate urea in real clinical samples. 

De Castro MDL, Fernandez Romero JM (1995) Development of an optical flow-through biosensor for the determination of sulphite in environmental samples. Anal Chim Acta... 

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