Biomedical Engineering Reference
In-Depth Information
culture method and the cyano-ditolyl-tetrazolium chloride (CTC) staining method for the
analysis of samples before the final chlorination (after GAC filtration) and drinking water
samples. The TVC method requires less time than others, is simple to use, and allows the
analysis of large volumes (100 ml) of drinking water [124].
Other Uses:
Research applications and understanding the relationship between the struc-
ture of a molecule and its biological function.
Device Development:
At the University of New Mexico we have developed two tech-
niques: flow-through using highly dispersed carbon particles and flow-through using
porous carbon membranes. The system comprises a flow-through, immunofiltration
technology and electrochemical-transduction principles. They are capable of detecting the
bacteria in the original samples without any preenrichment. With an overall assay time of
30 min and 20 min, these analytical systems will be simple to operate under field condi-
tions requiring minimal skills and can be easily adapted to detect other pathogenic bacteria.
Previous work was done using the highly dispersed carbon particles for the detection of
Hantavirus, which was very successful. The pore size of the disposable filter was deter-
mined on the basis of the size of the analyte. The process of selection of the filter-pore size
was also based on the “hook effect” [93,94]. So, the previously developed procedure for
the Hantavirus was adapted for the detection of
Salmonella
and
Shigella
after a few param-
eters were changed and optimized. The use of porous carbon membranes was decided
upon following previous trials using nylon membranes. The nylon membranes were non-
conductive, which led to a very small signal and correspondingly small detection range.
The carbon membranes were then chosen for their ability to simultaneously function as
the site of immunointeractionas well as the working electrode while maintaining the
advantages that come with a disposable membrane. We will survey most of the commer-
cially available equipment for monitoring and the detection of bacteria and virus, before
introducing our recent work.
21.3
Commercial Equipment for Monitoring Virus
21.3.1
Commercial Kits
21.3.1.1
B (Becton and Dickinson, Inc.)
With BD Directigen™ Flu A, it is possible to have Influenza A test that is not only easy to
perform and proven accurate, but also truly STAT (Figure 21.2) [125]. Most importantly, it
will help your laboratory quickly and confidently support critical antiviral therapy
recommendations. Truly STAT testing for Influenza type A offers the following features
with Directigen Flu A:
Directigen™ Flu A, Directigen™ Flu A
total hands-on time is about 5 min, thus reducing the technologist time;
●
instant, clear-cut readings;
●
helps rule out Influenza A from similar viral infections;
●
room-temperature storage of the entire kit;
●
good patient care with accurate results in minutes;
●
91% sensitivity and 95% specificity when compared to tissue culture; and
●
clear, accurate results in about 6 min for positive specimens.
●
Directigen™ Flu A Rapid Test Kit
Various specimen types include nasopharyngeal washes, nasopharyngeal aspirates, and
nasopharyngeal swabs. The Directigen Flu A rapid test is part of the line of rapid respiratory
