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Design variations of a polymer–enzyme composite biosensor for glucose: Enhanced analyte sensitivity without increased oxygen dependence
The glucose sensitivity and oxygen dependence of a variety of implantable biosensors based on glucose oxidase (GOx), incorporating an electrosynthesized poly- o-phenylenediamine (PPD) permselective barrier on 125-μm diameter Pt disks (Pt D) and cylinders (Pt C, 1-mm length), were measured and compar...
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Published in: | Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2005-07, Vol.580 (2), p.193-202 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The glucose sensitivity and oxygen dependence of a variety of implantable biosensors based on glucose oxidase (GOx), incorporating an electrosynthesized poly-
o-phenylenediamine (PPD) permselective barrier on 125-μm diameter Pt disks (Pt
D) and cylinders (Pt
C, 1-mm length), were measured and compared. Full glucose calibrations and experimental monitoring of solution oxygen concentration allowed us to determine apparent Michaelis–Menten parameters for glucose and oxygen. In the linear region of glucose response, the most sensitive biosensor design studied was Pt
D/PPD/GOx (enzyme deposited over polymer) that was ∼20 times more sensitive than the more widely used Pt
C/GOx/PPD (enzyme immobilized before polymer deposition) configuration. The oxygen dependence, quantified as
K
M(O
2), of both active and less active designs was surprisingly similar, a finding that could be rationalized in terms of an increase in
K
M(G) with increased enzyme loading. The Pt
D/PPD/GOx design will now enable us to explore glucose concentration dynamics in smaller and layered brain regions with good sensitivity and minimal interference from fluctuations in tissue
pO
2. |
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ISSN: | 1572-6657 1873-2569 |
DOI: | 10.1016/j.jelechem.2005.03.026 |