Enzyme collagen membrane for electrochemical determination of glucose

Abstract

International audienceA new trace glucose analyzer has been designed using electrochemical sensors. The differential device includes (a) a glucose sensor consisting of a modified gas electrode in which ihe pH detector was replaced by a platinum disk and the porous film by a collagen membrane on which beta-D-glucose oxidase has been covalently bound after an acyl-azide activation process; (b) a compensating electrode mounted with a nonenzymatic collagen membrane. After injection of a glucose containing sample into the reaction vessel, where the probes are immersed, an anodic current is detected at the enzyme working electrode. Current outputs of both electrodes are subtracted and twice differentiated; a steady state is reached and the stationary and dynamic responses are recorded. Both responses are proportional to glucose concentration in the 0.1 µM-2 mM range, and the reproducibility was found to be better than 2% using these conditions. The extreme sensitivity exhibited by our system, i.e., 10 nM, is better than previously reported data by 3 orders of magnitude, and is very favorable for trace glucose assays in food and biological samples

Use of Thermally Simulated Aging to Evaluate the Contribution of Constituents to the Activity of Mediated Carbon Paste Glucose Biosensors to Improve Their Shelf-Life

“…The operational stability of enzyme electrodes [3,13] is among the most frequently studied analytical parameter [14], while for storage stability only a few studies were achieved [15][16][17] because of the need of intermittent measurements which require long time periods. Therefore, the predictive determination of enzyme electrode activity, based on an artificial thermal aging, could be considered as an attractive method because it permits a rapid estimation of biosensor shelf-life.…”

A Glucose Electrode Using High-Stability Glucose-Oxidase Collagen Membranes

“…The correlation of the values ob- previous study, we found that the surface enzyme activities of glucose-oxidase membranes, which ranged from 8 to 80 mU/cm 2 in 0.1 M glucose, gave steady-state responses proportional to these activities. 6 Thus, the sole calibration of this glucose electrode, i.e., AI/AC, is a good way to monitor the surface activity of such glucose-oxidase membranes. Initially, all membranes were stored at 4°C before or between tests at 30°C.…”

Biosensor-based instrumentation

“…Enzymes have been first immobilized on collagen membranes through acylazide groups and used for the design of a selfcontained glucose electrode [6]. More recently, new types of polyamide ~upp01-t~ from Pall Industry S.A., France were selected to prepare bioactive membranes efficiently with a better reproducibility.…”

“…can be oxidized, yielding an undesirable output current and biased results. This can be overcome by a differential measurement with a twoelecrode system [6]. The two electrodes are equipped with the same type of membrane but the active electrode bears the grafted glucose oxidase whereas a plain membrane without enzyme is attached to the compensating electrode.…”