<i>In Vitro</i> and <i>In Vivo</i> Degradation of Glucose Oxidase Enzyme Used for an Implantable Glucose Biosensor

Valdes, Thelma I.; Moussy, Francis

doi:10.1089/15209150050194233

Cited by 51 publications

(39 citation statements)

References 21 publications

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“…Limits of detection were maintained at adequate levels to discern changes in glucose using the biosensor system. Production of hydrogen peroxide has been identified as the main agent for short-term enzyme degradation in vivo [76]. The lack of significant change in maximum current shows that the original enzyme activity was still present in the system after short-term use in vivo, supporting these previous findings.…”

Section: Performance Of Freshly Prepared and Resected Biotransducerssupporting

confidence: 78%

Biofabrication Using Pyrrole Electropolymerization for the Immobilization of Glucose Oxidase and Lactate Oxidase on Implanted Microfabricated Biotransducers

2014

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Abstract:The dual responsive Electrochemical Cell-on-a-Chip Microdisc Electrode Array (ECC MDEA 5037) is a recently developed electrochemical transducer for use in a wireless, implantable biosensor system for the continuous measurement of interstitial glucose and lactate. Fabrication of the biorecognition membrane via pyrrole electropolymerization and both in vitro and in vivo characterization of the resulting biotransducer is described. The influence of EDC-NHS covalent conjugation of glucose oxidase with 4-(3-pyrrolyl) butyric acid (monomerization) and with 4-sulfobenzoic acid (sulfonization) on biosensor performance was examined. As the extent of enzyme conjugation was increased sensitivity decreased for monomerized enzymes but increased for sulfonized enzymes. Implanted biotransducers were examined in a Sprague-Dawley rat hemorrhage model. Resection after 4 h and subsequent in vitro re-characterization showed a decreased sensitivity from OPEN ACCESSBioengineering 2014, 1 86 0.68 (±0.40) to 0.22 (±0.17) µA ·cm −2 ·mM −1 , an increase in the limit of detection from 0.05 (±0.03) to 0.27 (±0.27) mM and a six-fold increase in the response time from 41 (±18) to 244 (±193) s. This evidence reconfirms the importance of biofouling at the bio-abio interface and the need for mitigation strategies to address the foreign body response.

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Section: Performance Of Freshly Prepared and Resected Biotransducerssupporting

confidence: 78%

Biofabrication Using Pyrrole Electropolymerization for the Immobilization of Glucose Oxidase and Lactate Oxidase on Implanted Microfabricated Biotransducers

2014

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“…The formation of cracks and holes in the protective membranes of a biosensor will lead to changes in sensitivity, loss of linearity, and increased sensitivity from interferent molecules. Several studies have also shown that degradation of the GO x enzyme leads to decreases in glucose sensor response (Abel et al, 1999;Valdes and Moussy, 2000). However, for most biosensor designs an excess of enzyme is used, therefore lost enzyme activity is very seldom a problem, as was the case in the study by Updike et al (1994).…”

Section: Biosensor Degradationmentioning

confidence: 99%

Biosensors for real-time in vivo measurements

Wilson

Gifford

2005

Biosensors and Bioelectronics

597

351

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“…The sensitivity remained nearly constant from 10 to 70 days and, thereafter, a gradual reduction in sensitivity was observed until the end of the study period of 90 days ( figure 9). Build-up of H 2 O 2 within the enzyme layer during storage in 5 mM glucose solution in PBS could be a reason for the decrease in sensitivity, because H 2 O 2 was earlier demonstrated to deleteriously affect the function of GOx enzyme [38]. To circumvent this problem, excess loading of GOx was suggested [23], and our CNT fibers were loaded with excess enzyme per unit electro-active surface area.…”

Section: Amperometric Response Of the Biosensormentioning

confidence: 99%

Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

et al. 2010

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A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon source and an iron nano-catalyst. The fiber, 28 μm in diameter, was made of bundles of double walled CNTs (DWNTs) concentrically compacted into multiple layers forming a nano-porous network structure. Cyclic voltammetry study revealed a superior electrocatalytic activity for CNT fiber compared to the traditional Pt-Ir coil electrode. The electrode end tip of the CNT fiber was freeze-fractured to obtain a unique brush-like nano-structure resembling a scale-down electrical 'flex', where glucose oxidase (GOx) enzyme was immobilized using glutaraldehyde crosslinking in the presence of bovine serum albumin (BSA). An outer epoxy-polyurethane (EPU) layer was used as semi-permeable membrane. The sensor function was tested against a standard reference electrode.The sensitivities, linear detection range and linearity for detecting glucose for the miniature CNT fiber electrode were better than that reported for a Pt-Ir coil electrode. Thermal annealing of the CNT fiber at 250 •C for 30 min prior to fabrication of the sensor resulted in a 7.5 fold increase in glucose sensitivity. The as-spun CNT fiber based glucose 2 biosensor was shown to be stable for up to 70 days. In addition, gold coating of the electrode connecting end of the CNT fiber resulted in extending the glucose detection limit to 25 μM. To conclude, superior efficiency of CNT fiber for glucose biosensing was demonstrated compared to a traditional Pt-Ir sensor.

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In Vitro and In Vivo Degradation of Glucose Oxidase Enzyme Used for an Implantable Glucose Biosensor

Abstract: The presence of glucose in vitro and in vivo led to the production of H2O2, suggesting this to be the main agent responsible for enzyme degradation. The use of a Nafion coating did not provide any additional protection.

Cited by 51 publications

References 21 publications

Biofabrication Using Pyrrole Electropolymerization for the Immobilization of Glucose Oxidase and Lactate Oxidase on Implanted Microfabricated Biotransducers

Biofabrication Using Pyrrole Electropolymerization for the Immobilization of Glucose Oxidase and Lactate Oxidase on Implanted Microfabricated Biotransducers

Biosensors for real-time in vivo measurements

Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

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