Electrochemical Detection - Waterborne Pathogens: Detection Methods and Applications - page 164

shows that few electrochemical techniques have been evaluated for the
detection and analysis of waterborne pathogens. However, work performed
on other types of pathogens (i.e. human pathogen from other sources or
plant and animal pathogens) can be easily extended, in general, to water-
borne microorganisms and viruses. That is why our review is not limited to
waterborne pathogens.
Molecular imprinting technology was applied to design sensing elements
for the detection by potentiometry of virions of poliovirus in a specific man-
ner (no cross-reactivity to adenovirus and no response by a nonimprinted
sensor). 131 These findings demonstrated the application of the principles of
molecular imprinting to the development of a new method for the detection
of viruses. Sensors have been developed with immobilized single-stranded
DNA, complimentary to that of the viral DNA, on a glassy carbon solid-
phase transducer. Upon analyte binding, the newly formed double-stranded
DNA transferred electrons, which were detected by differential pulse voltam-
metry and linear sweep voltammetry. This method has been used by several
groups in the detection of Hepatitis B virus. Albers has reported the fabrica-
tion of Si-based biochip incorporating interdigitated ultramicroelectrodes of
high spatial resolution. 132 A fully electrical array for voltammetric detection
of redox molecules produced by enzyme-labeled affinity binding complexes
was shown by Nebling. 133 The electronic detection is based on ultramicro-
electrode arrays manufactured in silicon technology. It requires an electroac-
tive mediator, hydroxaniline, and has been used for the detection of virus
DNA in real, unpurified, and multiplex PCR samples. Ding implemented
a similar label-free biosensor for the detection of oligonucleotides related to
Hepatitis B virus sequence via the interactions of DNA with a redox-active
complex. 134 It measures the flow of electrons directly through the double-
stranded DNA helix, using only cobalt complexes that increased efficiency
and sensitivity, the limit of detection being 1.94×10 −8 M. 135 Detection of
anti-HIV antibodies in serum was reported by Laczka. 136 The novelty of the
work was the combination of allosteric enzymes and coulometry to yield a
fast, simple, and reliable HIV indirect diagnostic method. Detection of whole
viruses using CNT thin-film field-effect devices has been reported by Man-
dal. 137 Selective detection of M13-bacteriophage has been demonstrated
using a simple two-terminal configuration. Chemical gating through spe-
cific antibody-virus binding on the surface of a CNT has been proposed to
be the sensing mechanism. Compared to electrical impedance sensors with
identical microelectrode dimensions, this sensor exhibits a sensitivity, which
is five orders higher. Jarocka reported the development of an immunosensor