Oxygen Transport Characteristics of Refunctionalized Fluoropolymeric Membranes and Their Application in the Design of Biosensors Based upon the Clark-Type Oxygen Probe

Abstract

Surface refunctionalized fluoropolymer membranes were applied in the design of whole cell and enzyme biosensors based on the Clark-type oxygen sensor. Fluoropolymer membranes (poty(hexafluoropropylene-co-tetrafluoroethylene) (FEP)) were treated using a recently developed procedure that employs a hydrogen/methanol vapor radio frequency glow discharge plasma to introduce hydroxyl functionality into the polymer backbone in a controlled fashion. Hydroxylated materials were aminated by treatment with (y-aminopropyl)triethoxysilane (APTES). The surface amine groups served as attachment sites for whole cells and enzymes. Initial work measured the permeability and diffusion coefficients for oxygen in hydroxylated, aminated, and base (nonmodified) FEP membranes. Refunctionalized membranes retained the oxygen

Surface Modification of Fluoropolymers via Molecular Design

“…[26,27] Fluoropolymers have been widely used in space applications, [28,29] protective coatings, [30] microelectronics packaging, [12,31] and biotechnology. [32,33] Other basic materials properties of the fluoropolymers are widely available in the literature. [34±37] In a parallel development, the ever increasing demand for miniaturization and increased signal speed have resulted in a constant quest for useful materials with very low dielectric constants to replace the glass fiber±epoxy composites currently in use.…”

A Bipartite Expression for the Transient Amperometric Current at a Membrane Covered Planar Electrode to Characterize Solute Diffusion Through the Membrane

“…If diffusion coefficients are obtained by fitting Equation 4 to experimental currents for t > 1s [8] For 4-acetaminophenol, the diffusion coefficients through 0.05 and 0.025 mm pore diameter membranes in phosphate buffer are 1.96 Â 10 À7 and 1.21 Â 10 À7 cm 2 /s, respectively. So, available diffusion paths through the smaller pore size membrane are not reduced in proportion to pore size, this could be because pore density, tortuosity or connectivity was not equivalent for the two structures.…”

“…McBreen et al [5] proposed a planar electrode for the amperometric detection of hydrogen through a metal membrane forty years ago, and more recently, Kimble et al [7] estimated the diffusion coefficient of hydrogen through a propriety ion exchange membrane. Tarnowski et al [8] were similarly able to characterize oxygen transport at a refunctionalized fluoropolymeric membrane; Compañ et al [9,11] characterized oxygen diffusion through silicone and hydrogel membranes; Kim et al [10] determined oxygen transport through a fluorinated ethylene propylene membrane.…”

Modified gas-permeable silicone rubber membranes for covalent immobilisation of enzymes and their use in biosensor development

“…Alternatively, the enzyme was covalently immobilised on a second, hydrophilic membrane 14,15 which then was mechanically held in front of the oxygen sensor by an O-ring. Recently, covalent immobilisation of enzymes on commercially available gas-permeable polymer membranes has been described, [16][17][18] but these membranes have to be chemically activated prior to immobilisation during an additional reaction step.…”