Highly Selective Membrane-Free, Mediator-Free Glucose Biosensor

Abstract

Highly selective amperometric glucose sensors based on rhodium-dispersed carbon paste/glucose oxidase electrodes are described. The dispersed rhodium particles exhibit efficient and preferential electrocatalytic activity toward the liberated peroxide species and allow cathodic detection of the glucose substrate at -0.10 V, with no interference from easily oxidizable constituents. Such operation thus eliminates the need for interferant-eliminating enzyme layers, permselective membrane barriers, or artificial electron mediators, hence greatly simplifying the sensor design and fabrication. The sensor selectivity is illustrated in the presence of physiological levels of ascorbic acid, uric acid, acetaminophen, salicylic acid, tyrosine, urea, galactose, and glutathione. Attractive dynamic properties and high sensitivity are also achieved in the absence of membrane barriers. A stable response is observed over several months.Because of the high demand for blood glucose measurements (particularly for treatment and control of diabetes), significant research and development efforts have been devoted to producing reliable glucose sensors.1-1 2 Particular attention has been given to the development of single-use (disposable) strips for self-testing of blood glucose and to implantable devices for continuous in vivo monitoring of this sugar. Amperometric enzyme electrodes have received considerable attention in connection with these self-testing and in vivo applications.

Characterization in vitro and in vivo of the oxygen dependence of an enzyme/polymer biosensor for monitoring brain glucose

“…The latter remains the most common form of biosensor despite requiring a large overpotential at which reducing agents present in the sample can contribute to the faradaic current. Although some of the problems associated with anodic H 2 O 2 detection have been minimized by using electrocatalytic H 2 O 2 reduction at low potentials (Gao et al, 1992;Vreeke et al, 1992;Wang et al, 1994Wang et al, , 1996, the question of sensitivity to pO 2 appears in an additional form */the possibility of direct faradaic reduction of O 2 .…”

Electrochemical Immunoassay for Detecting Hippuric Acid Based on the Interaction of Osmium-Antigen Conjugate Films with Antibody on Screen Printed Carbon Electrodes

“…These results show that some of the interfering compounds such as ascorbic acid and uric acid in the human urine sample could be easily oxidized on the electrode. [34][35][36] However, the interference effects were far removed from the reduction peak of the Os redox probe in Figure 7. The inset of Figure 7 illustrates the peak current magnitude (i p,c ) at 0.34 V (vs. Ag/AgCl), according to the HA concentration (0, 0.1, 0.5, 1.0, 2.0, 4.0, 5.0 mg/mL).…”

Nanostructured Inorganic Materials at Work in Electrochemical Sensing and Biofuel Cells

“…As a matter of fact, electron transfer to the active center is a major limiting factor, which causes complicated electron transfer mechanisms. It should be noticed that other alternatives of reducing undesired reactions by decreasing the required potential for H 2 O 2 detection at about 0 V vs. Ag|AgCl|KCl sat , where fewer non-target species will be oxidized, lead to incorporating metallic species (Prussian blue, Rh or Ru) at the electrode surface [3,24,25]. Alternatively, horseradish peroxidase (HRP) enzyme [26][27][28] which oxidizes H 2 O 2 electrocatalytically at lower potentials without oxidizing any other components of the sample can be incorporated.…”