Biology Reference
In-Depth Information
Sample processing is a clear challenge that needs to be addressed to enable
biosensor use on environmental samples. We have discussed sample processing
methods in Chapter 4, but our experience of the biosensor literature is that
few authors consider the application of their technology to the large volume
water samples that need to be tested. Robustness and long-term operation for
field deployment are also issues that need to be addressed to meet the vision of
Rose and Grimes. Perhaps new recognition elements will play a role here in
delivering systems capable of long-term storage. Biofouling could also present
a challenge for testing water samples; again, sample processing has a key role
to play in reducing the potential number of interferents. Specificity of probes
is also important to avoid false positives, and indeed for some waterborne
pathogens availability of recognition elements is a challenge in itself. Immo-
bilization of recognition elements is also key to biosensor performance and
appears to receive less attention in the literature e.g. it is unclear from some
reports whether the recognition element and immobilization strategy have
been optimized. However, in terms of the advantages of biosensors, speed is
one particular benefit, as is the potential ease of portability of some detec-
tion schemes. One major disadvantage, however, is the lack of discrimi-
nation between different species as well as between viable and nonviable
pathogens.
With regard to future developments, it will be important to deliver
improved sensitivity along with cost-effectiveness and portability. In achiev-
ing the first of these goals, amplification strategies could play an important
role; one area of signal enhancement is through the use of nanotechnology,
as discussed in Chapter 9. Portability, as well as ease of operation even for
those with minimal training and experience, could be aided by the devel-
opment of microsystems. Miniaturized detection platforms are described in
Chapter 10, and those that are multiplexed for simultaneous detection of
multiple pathogens are particularly likely to prove popular. Integration with
sample processing units is also important to deliver devices that can detect
pathogens in real-world systems.
Future research should also explore other biosensing techniques for
viruses and protozoa, perhaps particularly electrochemical methods for
viruses and both optical and electrochemical methods for protozoa. Any
advances enabling species and viability discrimination would also be
extremely beneficial for the real-world application of biosensing technol-
ogy to waterborne pathogen detection.
In conclusion, biosensors represent a promising technology for waterborne
pathogen detection, with some examples now reaching single-pathogen
sensitivity, although there are still many challenges to be overcome.
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