Antimicrobial Peptides for Detection and Diagnostic Assays - Designing Receptors for the Next Generation of Biosensors - page 84

3.2 Biosensor-Based Detection Using Immobilized AMPs ............................. 92
3.3 High-Throughput Screening Platforms .............................................. 94
4 Issues and Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Abbreviations

AMP Antimicrobial peptide
Cfu Colony-forming units
HTS High-throughput screening
LPS Lipopolysaccharide
LTA Lipoteichoic acid
OAKs Oligoacyllysines
PCR Polymerase chain reaction
PMB Polymyxin B
QCM-D Quartz crystal microbalance with dissipation monitoring
SPR

Surface plasmon resonance

1 Conventional Approach for Pathogen Detection

The rapid and reliable detection of microbial pathogens, etiologic agents of chronic
or infectious disease is an important part of research in many fields, including
medical diagnosis, public health applications, environmental health control, and
biodefense. In recent years, many types of detection and diagnostic systems have
been developed for rapid, analytical detection and identification of pathogenic
microbes based on specific immunological or genetic characteristics of the target
organism. Antibody- and PCR-based assays are currently the most commonly
employed molecular techniques [ 1 ]. Antibodies provide a powerful analytical tool
for a wide range of targets. Immunoassays are highly specific, versatile, and the
antibodies bind strongly and stably to their respective antigen. Immunoassays are
perhaps the only approach that have been successfully employed for the detection
of bacterial cell, spores, viruses, and toxins alike [ 2 ]. PCR-based detection methods
are founded on the premise that each species of pathogen carries a unique DNA or
RNA signature that differentiates it from other organisms. Real-time PCR is highly
sensitive and allows for quantitation of microorganisms at any level of specificity
(i.e., strain, species, genus), and because the approach detects the organism by
amplifying the target DNA rather than the signal, it is less likely to produce false
positives [ 3 ]. These current approaches for identifying pathogens are sensitive and
selective but are subject to certain limitations. First, they rely on known
characteristics that may be altered by growth conditions (antigenic determinants)
or genetic engineering (DNA/RNA sequence). In addition, when multiplexing
assays for multiagent detection, background and nonspecific signals increase,
limiting the number of targets that can be detected.