Biosensors for the Detection of Waterborne Pathogens - Waterborne Pathogens: Detection Methods and Applications - page 182

excellent review articles and books focusing on different aspects of biosen-
sor technologies have been published in recent years; the reader is referred
to these for more detailed background information. 3-8 This chapter will
therefore focus on technologies already applied to waterborne pathogens or
on techniques that offer significant potential. An increasing body of research
in food pathogens and medical diagnostics has been undertaken. Where
appropriate, some of the literature on these topics is included here.
Biosensor Definitions
A biosensor can be defined as an integrated receptor-transducer device that is
capable of providing selective quantitative or semiquantitative analytical infor-
mation using a biological recognition element.
Biosensors have been defined as analytical devices incorporating a biologi-
cal material (e.g. tissue, microorganisms, organelles, cell receptors, enzymes,
antibodies, nucleic acids, natural products, etc.), a biologically derived material
(e.g. recombinant antibodies, engineered proteins, aptamers, etc.), or a biomimic
material (e.g. synthetic catalysts, combinatorial ligands, and imprinted polymers)
intimately associated with or integrated within a physicochemical transducer or
transducing microsystem, which may be optical, electrochemical, thermometric,
piezoelectric, magnetic, or micromechanical. 2
7.1. PERFORMANCE CHARACTERISTICS
The performance of biosensors can be characterized in terms of sen-
sitivity, specificity, detection limit, assay time, reproducibility, and precision
of results ( Table 7.1 ). The sample volume processed and the performance in
complex sample matrices are important factors, especially for waterborne
pathogens. Additional considerations are the ease of operation, which could
incorporate the degree of automation, the number of stages in the assay
protocol or the need for secondary or amplification steps, and the size/
portability of the system. These latter factors will influence the potential of
the system to be adopted as a field-based biosensor. Furthermore, the cost
of any sensor system is crucial to industry adoption. The potential of any
biosensor technology for multiplexing is also of interest to create simple
tools capable of analyzing multiple pathogens in one sample.
In the selection and optimization of a biosensor, trade-offs between vari-
ous performance characteristics have to be made, depending upon the exact
application. For example, a field-based early warning system will need to be