Electrochemical Detection - Waterborne Pathogens: Detection Methods and Applications - page 169

on the measured quantity, miniaturization cannot necessarily improve the
signal over noise ratio. We review the scientific literature about the use of
electrochemical biosensors for the detection of pathogens (Section 6.8 ) . We
did not restrict our analysis to studies dedicated to waterborne pathogen
because they are not studied as much. However, the interest in detection and
analysis of waterborne pathogen is growing, and electrochemical techniques
have a huge potential for water analysis. 164 We mention different approaches
developed by various research groups. Voltammetry and impedancemetry
are the most cited in recent years. The reported sensors have different com-
plexities, analysis times, sample preparation procedure, and detection limits
depending on the target pathogen. Improvements are still required to plan
large commercialization of this technique. Indeed, national and international
legislation require more and more information about the presence of patho-
gens in our environment and, in particular, in water. This information has
to be reliable, accurate, and low cost and should be available in a very short
time. To enhance the emergence of electrochemical biosensors for label-free
waterborne pathogen detection and analysis, we point out some improve-
ments that are primordial. The variability of electrochemical biosensors
needs to be systematically and thoroughly quantified. 165 If some reported
systems comprise multiple integrated biosensors to carry out this statisti-
cal analysis intrinsically, most works do not report on it. This lack of solid
statistical analyses maybe an important challenge for commercialization, dis-
suading industrialists and venture capitalists. 166 The inclusion of redundant
sensor elements for self-verification, the availability of back-up sensors for
enhanced longevity, and the use of recognized and rigorous statistical analy-
sis are highly desirable. 167,168 The costs of electrochemical biosensors need
to be decreased rapidly to be competitive with labeling or the other label-
free techniques. For this, the lifetime of biosensors can be improved and/or
the cost of materials and manufacturing processes can be decreased by using
organic electrodes, flexible substrates, printing, and roll-to-roll processes.
Analysis time has to be shorter than gold standard techniques. Analysis time
includes sample pretreatment, cultivation, extraction, etc. and detection. In
order to become more attractive, electrochemical biosensors need to show
that they are capable of reaching at least the same detection levels as tra-
ditional techniques (10-100 cfu mL −1 ). If significant advances have already
been accomplished with pure samples, we regret that only few devices have
been applied to real sample or handled in real conditions. Several obstacles
still have to be overcome such as the interfacing of the microsized bio-
sensors with the macrosized real world. 169 These include their association