Biology Reference
In-Depth Information
15.1 Introduction
In clinically and epidemiologically severe infectious diseases, the
rapid identification and detection of the causative organism is
crucial for effective control, management, and prompt treatment of
the infection. The conventional laboratory methods involve culture,
microscopy, and biochemical tests [1]. This process is laborious and
takes 2 to 4 days or longer to obtain a result. Culture methods often
lack sensitivity, especially for poorly handled samples or clinical
samples from patients previously treated with antibiotics[2].
Polymerase chain reaction (PCR) has been used extensively
as a diagnostic tool in various fields, such as genetic screening,
infectious disease diagnosis, forensics, environmental monitoring,
and veterinary science. PCR is an enzymatic process in which
specificregionsofDNAareamplified
in vitro
.Thisprocessamplifies
the target DNA exponentially to generate billions of copies from
a single copy in less than 1 h [3]. The conventional detection of
PCR amplicons by electrophoresis exposes the user to hazardous
chemicals, such as ethidium bromide and ultraviolet light. Other
safer detection techniques, such as capillary blotting and enzyme-
linked immunoassays, require multiple hybridization and washing
steps, which are labor-intensiveand timeconsuming.
15.2 Methods for the Detection and Identification of
Microorganism Utilizing Enzyme-Based Genosensors
on Screen-Printed Chips
15.2.1
Electrochemical Genosensors for the Detection of
Bacteria
Electrochemical genosensors for the detection of bacteria were
introduced about a decade ago. Miniaturization and advanced
microfabrication technology have made it compatible with bacteria
DNA diagnostic. This technology is cost effective, fast, and accurate.
The bioa
nity and biocatalysis reactions generate either amper-
ometric, voltametric, impedimetric, or conductimetric signals on
screen-printed transducer chips (SPC), which is proportional to the
numberof immobilizedDNA copies on the SPCsurface.
