In-device enzyme immobilization: wafer-level fabrication of an integrated glucose sensor

Wafer-level fabrication of integrated enzyme-based BioMEMS usually requires high temperature wafer-bonding techniques such as anodic bonding. Enzymes denature at comparatively low temperatures. Thus, enzymes need to be immobilized after wafer bonding. A convenient in-device immobilization method is...

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Bibliographic Details
Published in:Sensors and actuators. B, Chemical Vol. 99; no. 1; pp. 163 - 173
Main Authors: Zimmermann, Stefan, Fienbork, Doerte, Flounders, Albert W., Liepmann, Dorian
Format: Journal Article
Language:English
Published: Elsevier B.V 01-04-2004
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Summary:Wafer-level fabrication of integrated enzyme-based BioMEMS usually requires high temperature wafer-bonding techniques such as anodic bonding. Enzymes denature at comparatively low temperatures. Thus, enzymes need to be immobilized after wafer bonding. A convenient in-device immobilization method is presented allowing wafer-level patterning of enzymes inside micro-scale flow channels after wafer bonding. Enzymes are entrapped in a poly(vinyl alcohol)-styrylpyridinium (PVA-SbQ) membrane crosslinked by UV exposure through a transparent top wafer. The reaction kinetics of immobilized glucose oxidase is investigated in more detail. A low apparent Michaelis constant of 3.0 mM is determined indicating a rapid diffusion of glucose into the PVA-SbQ membrane as well as an oxygen-limited maximum catalytic rate. The entrapped glucose oxidase preserves its native properties since it is not chemically modified. Furthermore, the active PVA-SbQ membrane can be dehydrated in a vacuum and later rehydrated in buffer solution without significant loss of enzyme activity. An integrated enzyme-based glucose sensor fabricated on a wafer-level using in-device immobilization is described to demonstrate the potential of this novel technique. The sensor is part of a disposable microneedle-based continuous glucose monitor. The stability of glucose oxidase entrapped in PVA-SbQ is sufficient to continuously operate the sensor at 25 °C for 24 h.
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ISSN:0925-4005
1873-3077
DOI:10.1016/S0925-4005(03)00552-5