Techniques
contains minimal biomolecules required to sustain it
in a dormant period. For this reason, it has been
difficult to devise methods for detecting bacterial
presence in air without resorting to conventional,
slow techniques, such as growth on nutrient agar or
immunology. The intrinsic fluorescence in bacterial
spores can be measured by flow cytometry. Positive
identification of Bacillus anthracis (anthrax) spores
requires detecting a unique, identifying sequence
of nucleic acid — deoxyribonucleic acid (DNA) or
ribonucleic acid (RNA). The most definitive method
employs culture media to grow the microorganism.
However, several days are required to generate
sufficient nucleic acid quantities to achieve detection.
Conclusions
The aim of this review is to provide some information
on autofluorescence properties from living cells and
spores, as well as a new technique to biomonitor the
environment using autofluorescence for potential
applications in biothreat and biosecurity assessments
in the field. During the past few years, advanced
optoelectronic techniques have become available,
thus allowing spectroscopy and imaging to reveal
the signals emitted by endogenous fluorophores.
Because these molecules are often involved in
fundamental biological processes, they are
significant parameters for checking cells and spore
state. Consequently, analytical techniques based on
autofluorescence monitoring have great potential
both in research and biodefense, and the interest in
applying these new analytical tools both in vitro and
in vivo is growing. Autofluorescence microscopy
produces images with the contrast of the standard
histology without the use of exogenous stains and
provides additional information about structural
and functional features of the sample. The major
attraction of autofluorescence-based techniques is
to have, in principle, the capability of supplying
biochemical and morphological information about
the native state of the samples in real-time, without
any major alterations in sample preparation. Thus,
from a theoretical point of view, autofluorescencebased techniques could provide more information
with lower costs and fewer sampling errors, which
often occur in preparative procedures.
Vinod Jyothikumar, Ph.D., is an advanced imaging scientist
and biosafety manager at the W. M. Keck Center for Cellular
Imaging at the University of Virginia. He is a skilled microscopist
and molecular microbiologist with expertise in bacterial
genetic manipulations, sample preparations, and selection of
fluorophores and advanced microscopy techniques.
Electronic Military & Defense
■
www.vertmarkets.com/electronics
21