Portable Chemical Sensors: Weapons Against Bioterrorism

349 Pages·2012·11.86 MB·English

by  Georgia-Paraskevi Nikoleli

Portable Chemical Sensors
NATO Science for Peace and Security Series
This Series presents the results of scientifi c meetings supported under the NATO
Programme: Science for Peace and Security (SPS).
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(1) Defence Against Terrorism; (2) Countering other Threats to Security and (3) NATO,
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co-organized by scientists from NATO countries and scientists from NATO’s “Partner”
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developments in a subject to an advanced-level audience
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meetings supported under the programme earlier, may be found in the NATO Science
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with the NATO Emerging Security Challenges Division.
Sub-Series
A. Chemistry and Biology Springer
B. Physics and Biophysics Springer
C. Environmental Security Springer
D. Information and Communication Security IOS Press
E. Human and Societal Dynamics IOS Press
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Series A: Chemistry and Biology
Portable Chemical Sensors
Weapons Against Bioterrorism
edited by
Dimitrios P. Nikolelis
University of Athens, Greece
Published in Cooperation with NATO Emerging Security Challenges Division
Proceedings of the NATO Advanced Research Workshop on
Portable Chemical Sensors for the Rapid Detection of Chemical
and Biological Agents and Other Weapons of Terrorism
Lund, Sweden
1–4 July 2011
Library of Congress Control Number: 2012930649
ISBN 978-94-007-2874-5 (PB)
ISBN 978-94-007-2871-4 (HB)
ISBN 978-94-007-2872-1 (e-book)
DOI 10.1007/978-94-007-2872-1
Published by Springer,
P.O. Box 17, 3300 AA Dordrecht, The Netherlands.
www.springer.com
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Preface

A chemical sensor is a device that transforms chemical information, ranging from
the concentration of a specifi c sample component to total composition analysis, into
an analytically useful signal. Chemical sensors usually contain two basic compo-
nents connected in series: a chemical recognition element (“receptor”) and a physi-
cochemical transducer. The biological recognition system translates the chemical
information (i.e., concentration of the analyte) into a chemical or physical output
signal. The transducer (i.e., a physical detection system) serves to transfer the signal
from the output domain of the recognition element to the electrical, optical, or
piezoelectric, etc. domain. A biosensor is a self-contained integrated device which
is capable of providing specifi c quantitative analytical information using a biologi-
cal recognition element (e.g., enzymes, antibodies, natural receptors, cells, etc.)
which is retained in direct spatial contact with a transduction element. Recent
advances in the technology of artifi cial receptors have prompted a clear distinction
between chemical sensors and biosensors. The latter utilize a transduction element
of biological origin; however, since there has not been much development in engi-
neered molecules, both terms are and can used in the literature for this class of
devices. The chemical sensors should be clearly distinguished from an analytical
system which incorporates additional separation steps, such as liquid chromato-
graphy (LC) or additional hardware and/or sample processing such as specifi c
reagent introduction, e.g. fl ow injection analysis (FIA). Biosensors have not yet
made a large impact in the area of environmental, food, biomedical etc. applica-
tions, but clearly offer advantages in comparison to standard analytical methods,
such as minimal sample preparation and handling, real time detection, rapid detec-
tion of the analytes of concern, use of non-skilled personnel, etc. Because of the
importance of the ability of biosensors to be repeatedly calibrated, the term
multiple-use biosensor is limited to devices suitable for monitoring both the increase
and decrease of the analyte concentrations. Thus, single-use devices which cannot
rapidly and reproducibly be regenerated should be named single-etc.
The new biosensor technology has signifi cant technological advantages when
compared to that of the traditional non-sensor based detection methods. Portable
and handheld biosensors, for example, such as dynamic DNA and protein arrays for
v
vi Preface
rapid and accurate detection of pathogens are typical examples on how biosensor
technology can contribute in the defence against bioterrorism. For example, vesicles
for use in biosensors have both high specifi city and sensitivity, where the vesicles
include a receptor specifi c for the intended analyte and a signal generating
component.
A large class of chemical and biological sensors were based on the physical
characterization of interfaces. More specifi cally, electronic (bio)chemical sensing is
often related to the characterization of interfaces between ion-based and electron-
based conductive materials by means of electrical variables such as voltage, current
and charge. Also recent trends of integrated electronics that have started a revolu-
tion in this fi eld allowing the shrink of very complex electronic systems into milli-
metre square sizes were a follow-up in the literature. This would allow implementing
complex and sophisticated instrumentation in cheap and portable devices for a fast
detection of harmful and toxic agents.
The aim of this book is to bring into focus this important research area and
advances of biosensors and more specifi cally to those related to the rapid detection
of weapons of bioterrorism. The object is related to present advances in the develop-
ment of portable chemical sensors for the rapid detection of chemical weapons of
terrorism; the scope is related to provide a comprehensive review of the research
topics most pertinent to the advances of devices that can be used for the rapid real-
time detections of toxicants such as microbes, pathogens, toxins, nervous gases
eg. as botinilium toxin, Escherichia coli, K. Pneumoniae, sarin, VX, listeria mono-
cytogenes, salmonella, marine biotoxins (such as palitoxins, spirolides, etc.),
staphylococcal enterotoxin B, saxitoxin, gonyautoxin (GTX5), francisella spore virus,
bactillus subtilis, ochratoxin. Biosensors have found a large number of applications
in the area of environmental, food and biomedical analysis. Recent advances include
portable devices for the rapid detection of insecticides, pesticides, food hormones,
toxins, carcinogenic compounds in environment, such as polycyclic biphenols, etc.
Despite the public’s anticipation that biosensors with real-time detection will be
able to monitor biological and chemical weapons, the technology has not caught up
with expectations. Presently, biosensors in environmental monitoring stations
nationwide can detect compounds like anthrax—but detection can take 12–24 h.
The best ones on the market take 20 min. The detection of explosives and especially
of biomolecules (bacteria) is an important part of security and defence activities.
Technology has enhanced the possibility of combining the functions of drugs and
explosives through different bio-cells in the same analysis module. A testing plat-
form has been developed that has built-in confi guration fl exibility, which allows it
to be used for different applications such as chemical, explosives, drug and biologi-
cal agents detection. The characteristics of detection are determined by the combi-
nation of bio-cells. It is a new biosensor technology and helps users combine a
number of different detection tasks within the same test, without having to repro-
gram the instrument.
Biosensors have not yet a large impact in the area of rapid detection of chemical
and biological agents and other weapons of terrorism. Terrorists may use biological
agents because they are rather easy to prepare and can be extremely diffi cult to
Preface vii
detect. A biological weapon is useful to terrorists mainly as a method of creating
mass panic and disruption to a society.
Types of agents include anthrax, smallpox, botulinum toxin, bubonic plague,
epsilon toxin of C lostridium perfringens , food threats (e.g., S almonella species ,
E. coli O157:H7, Staphylococcus aureus ), s taphylococcal enterotoxin B, typhus
( Rickettsia prowazekii ), viral encephalitis, water supply threats (e.g., C ryptosporidium
parvum ), etc. In fact these agents are emerging pathogens that might be engineered
for mass dissemination because availability, easy to produce and disseminate, and
possess high mortality or a major health impact.
Most reports in the literature suggested that biosensors were at a pre-competitive
stage, but highlighted laboratory proof–of-concept. Presently, we are looking into
portable and handheld biosensors, for example, such as for example dynamic DNA
and protein arrays for rapid and accurate detection of pathogens. A few challenges
for biothreat detection had a high sensitivity – d etect very small amounts of patho-
gens, toxins, and chemical agents, high selectivity – d iscriminate targets from other
materials, massively parallel to detect multiple pathogens, minimize false positive,
have rapid response, without sample preparation, and inexpensive, To have high
spatial resolution, time resolution, selectivity and sensitivity for chemical and bio-
sensors nanowires and potentiometric measurements were used. Techniques which
in principle give some nanometer resolution of the area where we want to measure
were presented in the literature.
Electrochemical systems based on inhibition of acetylcholinesterase suggest that
the detection of nerve agents can be accomplished with fast speed and sensitivity
down to fmolar levels. Detection routes using antibodies and DNA provide many
advantages such as high sensitivity of detection, selectivity and can be used by non-
skilled personnel. A wealth of ideas for portability of the sensors was recently pre-
sented in the literature. Electroanalytical and optical strategies involving exploiting
methods based on the use of immunosensors and genosensors were presented.
The combination of screen-printed electrodes with functionalized magnetic beads
constitutes a powerful and effi cient strategy for the development of disposable
magneto-biosensors for the rapid and ultrasensitive detection of many analytes of
bioterrorism signifi cance. Magnetic micro- and nanoparticles have a large active
surface area which makes possible the immobilization of a high concentration of
biomolecules onto the solid phase of the transducer as well as a decrease of matrix
effects.
Protein and even cell detections methodologies with interest for various applica-
tions were based on nanotechnology (i.e. nanoparticles, nanochannels). Nanoparticles
based immunosensing systems were offered as excellent screening alternatives to
sophisticate and high cost equipments that require well prepared professionals for
their use, including data treatment, prior obtaining of fi nal results with interest for
further decisions taken in analysis/screening scenarios.
Development of a sensitive and specifi c biosensor for rapid detection of microor-
ganisms and protein toxins often requires the information on the identity of the
analyte of interest. On the other hand, recent advances in microbiology and biotech-
nology have lead the possibility of creating new microorganisms as well as production
viii Preface
of new protein toxins with completely or partially unknown DNA or protein
sequences. Thus, rapid identifi cation of microorganisms and protein toxins not only
enables the detection of the bio-agents but also facilitates the development of highly
portable biosensors for fi eld use.
Biosensors based on DNA aptamers are of growing interest due to their high
sensitivity and selectivity comparable with that of antibodies. Aptamers can be
chemically modifi ed by biotin, thiol or amino groups, which allowing them to be
immobilized on various solid supports. Aptamers can thus be considered as a valid
alternative to antibodies or other bio-mimetic receptors, for the development of
biosensors. The production of aptamers is commonly performed by the SELEX
(Systematic Evolution of Ligands by Exponential Enrichment) process, which,
starting from large libraries of oligonucleotides, allows the isolation of large amounts
of functional nucleic acids by an iterative process of in vitro selection and subse-
quent amplifi cation through polymerase chain reaction. Aptamers are suitable for
applications based on molecular recognition as analytical, diagnostic and therapeu-
tic tools.
Overall, the impact of biosensors for the rapid detection of chemical and biologi-
cal agents and other weapons of terrorism can be realized. This will require focused
further experimental work on the following challenges:
1. High sensitivity – i.e., detection of very small amounts on the order of fmolar
range of pathogens, toxins, and other chemical agents.
2. Highly selective – d iscriminate target compound from similar materials
3. Simultaneous detection of multiple pathogens and multiple molecular signatures
of the same pathogen to minimize false positive responses
4. Have rapid response, without sample preparation
5. Transportable or handheld, inexpensive, robust, simple to operate
6. Real-time monitoring of protein binding to aptamers at single molecule level.
7. Selectivity of protein detection, i.e., selectivity of human thrombin detection by
anti-thrombin aptamers
The ongoing war on terrorism and the rising security concerns are driving the
need for newer faster detection biosensors against bio-warfare agents for military
and civil defence applications.
The volume brings together contributions from the most eminent international
researchers in the fi eld, covering various aspects work that has not published in any
scientifi c journal and science beyond the “state of art” in this fi eld or even commer-
cial units that are available in the market. Very low detection limits e.g. 10− 17 M are
reported and novel detection schemes for existing or new pathogens, toxins and
other bioterrorism weapons are presented. Inexpensive, robust portable miniatur-
ized highly selective biosensing systems that were able to detect multi pathogens
without sample preparation are the targets of the present review articles; this will
give the opportunity to learn new technological schemes that will lead to the con-
struction of devices against bioterrorism that will minimize the risk of weapons of
terrorism. Classical detecting schemes such as electrochemical, surface plasmon
resonance (SPR), fi eld effect transistors, quartz piezoelectric acoustic method,
Preface ix
electrochemical impedance spectroscopy (EIS), and photoluminescence and other
optical physical sensors are presented.
Work on rapid identifi cation of microorganisms and protein toxins by proteomics
is an issue that is well presented and the participants of the volume have the oppor-
tunity to present their techniques on how to bind the transduction element into the
physical sensor unit. Novel techniques of transduction such as nanowiring, nanopar-
ticles or molecular imprinted polymers are presented and mainly some of these
transducers are able to be implanted in the human body. Target analytes detected
include a wide range of microbes, pathogens, toxins, nervous gases such as botini-
lium toxin, Escherichia coli, K. Pneumoniae, sarin, VX, listeria monocytogenes,
salmonella, marine biotoxins (such as palitoxins, spirolides, etc.), staphylococcal
enterotoxin B, saxitoxin, gonyautoxin (GTX5), francisella spore virus, bactillus
subtilis, ochratoxin A, cholera toxin, etc. Emphasis is given to the simultaneous
analysis of multiple species screen printed low density microelectrode arrays that
were used to develop genosensors to detect Salmonella SSP and staphylococcus
aureus. Scanning electrochemical microscopy is used to monitor listeria monocyto-
genes. An approach of detection using chronoamperometry coupled to microfl uid-
ics is developed to monitor legionella pneumonophila. Chemical transduction
biological elements acting as “receptor” such as antibodies, enzymes, DNA, RNA,
lipids, natural and artifi cial receptors were immobilized on the physical sensor to
recognize the target analyte.
In preparing the book, we have relied on the timely contribution of authors, with-
out whose expert insight, motivation and commitment the publication of this vol-
ume would not have been possible. We, thus, extend appreciation to all the authors.
We also convey our thanks to Springer for affording us the opportunity to publish
this volume and to the editorial and publishing stuff, in particular Wil Bruins, for
their assistance, organization and effi ciency in coordinating the timely preparation
and production of the book. We are also grateful to the North Atlantic Treaty
Organization for their valuable support of the Advanced Research Workshop on
Portable chemical sensors for the rapid detection of chemical and biological agents
and other weapons of terrorism, Lund, Sweden, which served as the original impe-
tus for the publication of this volume.
Dimitrios P. Nikolelis