Biosensors for the Detection of Waterborne Pathogens - Waterborne Pathogens: Detection Methods and Applications - page 179

CHAPTER SEVEN
Biosensors for the Detection
of Waterborne Pathogens
Helen Bridle 1 , Marc Desmulliez 2
1 Heriot-Watt University, Institute of Biological Chemistry, Biophysics and Bioengineering,
Riccarton, Edinburgh, Scotland
2 Heriot-Watt University, Institute of Sensors, Signals & Systems, Riccarton, Edinburgh, Scotland
Biosensors are devices that comprise a target recognition element, which is
biological, coupled with a mechanism of signal transduction. The function
of a biosensor is to convert a biological recognition event into a detectable
signal by the action of the transducer and signal conditioning electronic cir-
cuitry, thereby providing selective quantitative or semiquantitative analytical
information ( Fig. 7.1 ). Common recognition elements include enzymes,
antibodies, DNA, or even whole cells. These elements bind either cells and
cell fragments or nuclei acids or amplification products from molecular
methods present in the solution. This chapter will focus on biosensors,
which capture whole pathogens, rather than e.g. the amplification products
of molecular methods, which will be covered in Chapter 8.
Signal transduction can be performed using electrochemical, optical,
mass-sensitive, or thermal means. The first three methods are by far the most
popular and will be the focus of this chapter. Various combinations of these
transduction mechanisms give rise to many different biosensing technologies.
Automation and miniaturization of biological analytical techniques com-
bined with the development of on-line and remote measurement equipment
can be achieved through biosensor technology. Other oft-quoted advantages
of biosensors include short analysis times, low-cost assays, portability, and
real-time measurements.
Since Clark and Lyon developed the first biosensor for glucose detection
in 1962, biosensors have been intensively studied and extensively utilized in
various applications ranging from public health and environmental monitor-
ing to homeland security and food and water safety. In terms of pathogen
detection biosensors, Lazcka and colleagues found from an analysis of pub-
lication outputs that biosensors ranked fourth in 2007 in a comparison of
different technologies for pathogen detection and reported that biosensors
are the fastest growing technology for this application ( Fig. 7.2 ). 2