In vitro and in vivo Performance and Lifetime of Perfluorinated Ionomer-Coated Glucose Sensors after High-Temperature Curing

Moussy, Francis; Jakeway, Stephen; Harrison, David J.; Rv, Rajotte

doi:10.1021/ac00094a007

Cited by 120 publications

(75 citation statements)

References 25 publications

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“…For a glucose biosensor, Nafion serves four purposes, namely: a) to reject large, negative molecules [18], b) to physically protect the glucose oxidase enzyme that drives the chemical reaction of the biosensor (acting as a physical barrier), c) to act as a glucose transportlimiting membrane, thereby reducing the oxygen requirement of the biosensor and d) to maintain some level of biocompatibility, especially after curing of the Nafion membrane [19].…”

Section: Introductionmentioning

confidence: 99%

Surface modification of a perfluorinated ionomer using a glow discharge deposition method to control protein adsorption

et al. 2008

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Nafion™ is the membrane material preferred for in situ glucose sensors. Unfortunately, surface properties of Nafion promote random protein adsorption and eventual foreign body encapsulation thus leading to loss if glucose signal over time. Here we detail surface modifications made by RF plasma deposition to Nafion with the intent to prevent random protein adsorption while providing enough functional sites (hydroxyl groups) to bind a biologically active peptide known to induce cellular adhesion (YRGDS). Nafion surfaces were modified by RF plasma polymerizing five different combinations of (1) tetraethylene glycol dimethyl ether (tetraglyme) and (2) 2-hydroxyethyl methacrylate (HEMA): pure tetraglyme, 2.5% HEMA/97.5% tetraglyme; 5% HEMA/95% tetraglyme, 10% HEMA/90% tetraglyme; and pure HEMA. Resultant surfaces were characterized by XPS (low and high resolution), dynamic contact angle, and atomic force microscopy. Protein adsorption and retention was determined and correlated to surface layer composition. The ability to bind a cell adhesion peptide was also determined and correlated well with surface layer composition.

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Section: Introductionmentioning

confidence: 99%

Surface modification of a perfluorinated ionomer using a glow discharge deposition method to control protein adsorption

et al. 2008

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“…Urate is a normal, readily electrooxidized, serum component [13,14]. Its electrooxidation damages glucose electrooxidizing anodes poised at potentials positive of 0.2 V (Ag/AgCl) [15].…”

Section: Introductionmentioning

confidence: 99%

Irreversible and Reversible Deactivation of Bilirubin Oxidase by Urate

2007

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Oxygen is electroreduced to water on a carbon cathode coated with wired bilirubin oxidase in a pH 7.4 0.15 M NaCl phosphate buffer solution at 37 8C at much lesser polarization than it is on a pure platinum cathode in 0.5 M H 2 SO 4 . While the wired bilirubin oxidase cathode operates for over a week in the aerated or oxygenated buffer solution, it is degraded rapidly when in serum. We reported earlier that in the presence of O 2 an intermediate product of the electrooxidation of urate, which is a normal serum component, irreversibly damages the wired bilirubin oxidase and also reported that the electrocatalyst is irreversibly damaged, in the absence of urate, when it is brought, by disconnecting the electrode, to the O 2 /H 2 O half cell potential at pH 7.4. Here we report that a) dissolved bilirubin oxidase is irreversibly and rapidly damaged by urate in the presence of O 2 ; and b) that the immobilized wired bilirubin oxidase electrocatalyst is not only irreversibly deactivated by urate in the presence of O 2 in a few hours, but is initially reversibly deactivated, in 1 min or less, by the urate in the presence of O 2 .

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“…[11][12][13][14] When Nafion, as a biocompatible membrane, is cast on the Kel-F layer, it is deposited more compactly with smaller particle size than Kel-F (Figs. 3e and 3f).…”

Section: Resultsmentioning

confidence: 99%

In vitro and Short-term in vivo Characteristics of a Kel-F Thin Film Modified Glucose Sensor

et al. 2003

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The enzyme-based biosensors for continuous glucose monitoring have long been investigated as a promising method of improving glycemic control in persons with diabetes. However, in vitro and in vivo functions of sensors still remain to be further improved to allow wide-spread use of an implantable real-time sensor.First of all, as for a GOx-based sensor, which requires oxygen as a co-substrate to carry out glucose oxidation, it is important to examine the so-called "oxygen effect", which means the dependence of the sensor performance on the oxygen supply. Zhang et al. 1 demonstrated that the demand for oxygen by the sensor is primarily determined by its sensitivity, because the absolute current output is a direct measure of the rate of oxygen consumption. Non-linear sensors exhibit a strong oxygen dependence because the overall process depends on oxygen and glucose fluxes. Many efforts to minimize the oxygen effect have included the use of proper membrane coverage that improves the surface availability of oxygen relative to glucose. Gough et al. 2 reported a novel sensor configuration in which oxygen diffuses into the membrane from two directions while glucose diffuses from only one. Wang and Lu 3 used Kel-F oil, which has very high oxygen solubility, as an internal supply of oxygen for a carbon paste electrode. However, this type of sensor has not yet been successfully implanted in a body to monitor glucose concentration in diabetes. Zhang et al. constructed a practically useful implantable glucose sensor, which was essentially free of oxygen fluctuation, by controlling the sensor's sensitivity and linearity. Sensitivity was controlled by the thickness of an outer polyurethane membrane. The outer layer served to increase the relative oxygen supply because it functioned only as a diffusion barrier to glucose, while it imposed little or no effect on oxygen diffusion.The second issue is to develop a reproducible and predictable method for sensor fabrication. When an enzyme layer is prepared on a miniaturized/microfabricated needle or a microfabricated electrode, electropolymerization has valuable advantages over solvent casting because it is not limited in terms of the geometry and area of the electrode. The method also offers a site-selectivity that makes it suitable for the development of a multianalyte-sensing system, and the uniformity of the polymer film on the electrode surface can cope with more complex geometries. 4,5 Yang et al. fabricated a miniaturized glucose sensor using microfabrication and electropolymerization techniques.6 Glucose oxidase (GOx) was entrapped during the electropolymerization of a 1,3-diaminobenzene (1,3-DAB) on a recessed rectangular microfabricated platinum electrode. On the other hand, many GOx-based sensors prepared by electropolymerization have suffered from problems due to a restricted linear response range, though they have shown high sensitivities and fast responses. As was demonstrated in the study reported by Zhang et al., the restricted linear response range results from ...

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In vitro and in vivo Performance and Lifetime of Perfluorinated Ionomer-Coated Glucose Sensors after High-Temperature Curing

Cited by 120 publications

References 25 publications

Surface modification of a perfluorinated ionomer using a glow discharge deposition method to control protein adsorption

Surface modification of a perfluorinated ionomer using a glow discharge deposition method to control protein adsorption

Irreversible and Reversible Deactivation of Bilirubin Oxidase by Urate

In vitro and Short-term in vivo Characteristics of a Kel-F Thin Film Modified Glucose Sensor

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