14
2.3 Overview of Predominant Sensing Techniques
Sensing can be explained as the use of recognition elements (biological in origin)
for binding to the biothreat molecule of interest. The binding event must be
transduced in a manner that signals the presence of the targeted analyte. Biosensor
probes are becoming increasingly complicated, mainly owing to the combination of
advances in two technological fields: microelectronics and biotechnology.
Biosensors are highly valuables devices in measuring a wide spectrum of BA
analytes [18, 19].
Ideally, each sensing detection technology should contain the following
characteristics:
Specific and able to discriminate between closely related pathogenic and nonpathogenic
organisms or toxins.
Sensitive and able to detect small amounts of the target within a high background matrix.
Possess high affinity and being able to maintain binding even through repeated washing steps.
Stable enough to allow long-term use.
It should be understood that luminescence biosensing technology is totally distinct from
other physicochemical methods, such as mass spectrometry (MS) or Fourier transform
infrared spectroscopy (FTIR) and Raman based analysis. These methods, of course, have
their merits and are very sensitive and specific. Therefore, in the following sections, we will
provide an overview of the state-of-the-art prime molecular sensing technologies for the
detection of BAs.
2.3.1 Pathogenic Bacteria Electrical Detection Via
Immobilized Antimicrobial Peptides
It is well known that the current methods for detecting pathogenic bacteria, which
include ELISA and PCR [20, 21], are assays that exploit antibodies as molecular
recognition elements due to their highly specific targeting of antigenic sites.
Nonetheless, these antibodies lack the stability needed to detect pathogenic species
under harsh environments and necessitate a one-to-one pairing of antibody-based
sensors for each analyte to be detected. Whereas nucleic acid probe-based techniques
such as PCR can reach single-cell detection limits, they still need the extraction of
nucleic acids and are limited in portability [21, 22].
It should be noticed that the synthesis of antimicrobial peptides (AMPs) and their
resulting intrinsic stabilities render them to be commonly selected for their use as
molecular recognition elements in electronic biosensing platforms [23–25]. AMPs
do exist in nature and are located either in the skin of higher organisms and/or in the
extracellular milieu of bacteria [25]. The replacements of current antibody-based
affinity probes, with more stable and durable AMPs in biological sensors, have a
J. H. Banoub and A. Mikhael
2.3 Overview of Predominant Sensing Techniques
Sensing can be explained as the use of recognition elements (biological in origin)
for binding to the biothreat molecule of interest. The binding event must be
transduced in a manner that signals the presence of the targeted analyte. Biosensor
probes are becoming increasingly complicated, mainly owing to the combination of
advances in two technological fields: microelectronics and biotechnology.
Biosensors are highly valuables devices in measuring a wide spectrum of BA
analytes [18, 19].
Ideally, each sensing detection technology should contain the following
characteristics:
Specific and able to discriminate between closely related pathogenic and nonpathogenic
organisms or toxins.
Sensitive and able to detect small amounts of the target within a high background matrix.
Possess high affinity and being able to maintain binding even through repeated washing steps.
Stable enough to allow long-term use.
It should be understood that luminescence biosensing technology is totally distinct from
other physicochemical methods, such as mass spectrometry (MS) or Fourier transform
infrared spectroscopy (FTIR) and Raman based analysis. These methods, of course, have
their merits and are very sensitive and specific. Therefore, in the following sections, we will
provide an overview of the state-of-the-art prime molecular sensing technologies for the
detection of BAs.
2.3.1 Pathogenic Bacteria Electrical Detection Via
Immobilized Antimicrobial Peptides
It is well known that the current methods for detecting pathogenic bacteria, which
include ELISA and PCR [20, 21], are assays that exploit antibodies as molecular
recognition elements due to their highly specific targeting of antigenic sites.
Nonetheless, these antibodies lack the stability needed to detect pathogenic species
under harsh environments and necessitate a one-to-one pairing of antibody-based
sensors for each analyte to be detected. Whereas nucleic acid probe-based techniques
such as PCR can reach single-cell detection limits, they still need the extraction of
nucleic acids and are limited in portability [21, 22].
It should be noticed that the synthesis of antimicrobial peptides (AMPs) and their
resulting intrinsic stabilities render them to be commonly selected for their use as
molecular recognition elements in electronic biosensing platforms [23–25]. AMPs
do exist in nature and are located either in the skin of higher organisms and/or in the
extracellular milieu of bacteria [25]. The replacements of current antibody-based
affinity probes, with more stable and durable AMPs in biological sensors, have a
J. H. Banoub and A. Mikhael