Biomedical Engineering Reference
In-Depth Information
The dynamic range with respect to response should be as high as possible
for certain targets (for example, clinical values of an analyte may vary
considerably).
With regard to real-time detection, speed of response is crucial. For the
one-time determination device this aspect may not be so important.
Device response calibration in terms of concentration is mandatory and
especially important for the real-time sensor. This feature has constituted
an extremely di
cult problem when it comes to, for example, the
operation of a corporeal implantable structure. Early solutions to this
issue may well lie in a strategy of device self referencing.
5
User ease of use may well be a factor especially where expertise in device
understanding is lacking.
There are ancillary issues such as robustness and cost which may be crucial
from a more commercial point of view.
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A bibliography of texts that deal with biosensor technology and related subject
matter is provided at the end of this chapter.
1.2 Genesis of Biosensor Technology
The advent of biosensor technology has been widely attributed to the work of
Clark and Lyons,
6
which involved an electrochemical amperometric
mechanism for the measurement of glucose concentrations in biological
samples. Prior to this system (1950s), Clark et al.
7
were working on the electro-
chemical detection of oxygen dissolved in blood and tissue via O
2
reduction, and
this research served as something of a precursor to the subsequent developments
with glucose.
The basis of the original glucose measurement was an enzyme electrode
(Figure 1.2) in which a layer containing the enzyme, glucose oxidase (GO) was
Figure 1.2
Schematic of a typical design of an enzyme (glucose oxidase) electrode.
