Electrochemical glucose biosensors - Electrochemical Sensors, Biosensors and Their Biomedical Applications - page 58

TABLE 3.1
Historical landmarks in the development of electrochemical glucose biosensors

Date Event Ref.

1962 First glucose enzyme electrode [3]

1973 Glucose enzyme electrode based on peroxide detection [6]

1975 Launch of the fi rst commercial glucose sensor system YSI Inc.

1982 Demonstration of in-vivo glucose monitoring [36]

1984 Development of ferrocene mediators [7]

1987 Launch of the fi rst personal glucose meter Medisense Inc.

1987 Electrical wiring of enzymes [12]

1999 Launch of a commercial in-vivo glucose sensor Minimed Inc.

2000 Introduction of a wearable non-invasive glucose monitor Cygness Inc.

activity towards the establishment of electrical communication between the redox center
of GOx and the electrode surface [12, 13], and the development of minimally invasive
subcutaneously implantable devices [14, 15]. Table 3.1 summarizes major historical
landmarks in the development of electrochemical glucose biosensors.

3.3 FIRST-GENERATION GLUCOSE BIOSENSORS

First-generation devices have relied on the use of the natural oxygen cosubstrate, and
the production and detection of hydrogen peroxide [Eqs (1)-(2)]. Such measurements
of peroxide formation have the advantage of being simpler, especially when miniatur-
ized sensors are concerned. A very common confi guration is the YSI probe, involving
the entrapment of GOx between an inner anti-interference cellulose acetate membrane
and an outer diffusion-limiting/biocompatible polycarbonate one (Fig. 3.1).

3.3.1 Redox interferences
The amperometric measurement of hydrogen peroxide requires application of a potential
at which endogenous reducing species, such as ascorbic and uric acids and some drugs
(e.g. acetaminophen), are also electroactive. The anodic contributions of these and other
oxidizable constituents of biological fl uids can compromise the selectivity and hence
the overall accuracy. Extensive efforts during the 1980s were devoted to minimizing
the error of electroactive interferences in glucose electrodes. One useful strategy is to
employ a permselective coating that minimizes access of such constituents to the trans-
ducer surface. Different polymers, multilayers and mixed layers, with transport prop-
erties based on size, charge or polarity, have thus been used for discriminating against
coexisting electroactive compounds [16, 17]. Such fi lms also exclude surface-active