Miniaturized Detection Systems - Waterborne Pathogens: Detection Methods and Applications - page 317

magnitude. 46,47 However, these gradients are temporally static. Serpentine
and twisted channel structures, 48 as well as channels containing chevron 49
or grooved structures, 50,51 have also been applied to create chaotic advec-
tion and enhance mixing.
10.2. APPLICATIONS
Microfluidics has found many applications within biology in general,
some of which could be extended to waterborne pathogens. For example,
there have been developments in using microfluidics to obtain better envi-
ronmental control over cells during culture, including bacteria, 52 and this
could be a potential development for traditional culture based approaches.
Microfluidics might also allow the design of environments to promote
culture of microorganisms which have not yet been cultured in the lab.
Yoon and Kim, however, are not positive about this approach for foodborne
pathogens with the justification that lab-on-a-chip has focused on rapid
methods of detection while culturing is time-consuming. 3 Their review
from 2012 is an excellent overview of microfluidic detection methods and
the latest application to foodborne pathogens, 3 many of which are identical
to waterborne pathogens. Another review of microfluidics for pathogens is
that by Mairhofer in 2009. 53 For consideration of how microfluidics might
apply in developing world settings the Nature review by Yager is recom-
mended. 54
This section will describe microfluidic applications of the detection
methods described in Chapters 5-8. However, one of the main challenges
for microfluidic devices in environmental applications such as waterborne
pathogen monitoring is the large sample volumes and complex matrices. For
medical applications the ability of microfluidics to deal with small sample
volumes is an advantage, though here lab-on-a-chip systems are proven to
deal with complex samples, like blood. There are, however, many techniques
utilized for cell sorting within microfluidics and this section will start with
an introduction to these and their applications to waterborne pathogens,
along with other waterborne pathogen sample processing on-chip.
10.2.1. In sample processing
A large number of papers have been published discussing cell sorting in
microfluidics, and there are many excellent reviews of the topic including
Refs 55 and 56 . Methods can be sorted into those which exploit intrinsic