Researchers from Lawrence Livermore National Laboratory review several of the latest technologies in the most recent issue (Issue 3, 2007), of the British journal “The Analyst,” which appears online at http://www.rsc.org/Publishing/Journals/AN/Article.asp?Type=CurrentIssue.
“It’s important to provide a summary of the latest technologies and approaches for sensing systems and platforms that could lead to bioagent detectors for responders to use in the field,” said LLNL’s lead author Jeffrey Tok. Other authors include Nicholas Fischer and Theodore Tarasow of LLNL’s BioSecurity and Nanosciences Laboratory.
One technique, previously described by Tok and colleagues, involves using a barcode system, similar to the barcodes used on retail products, to detect biological agents in the field. Nanowires built from sub-micrometer layers of different metals, including gold, silver and nickel, are able to act as “barcodes” for detecting a variety of pathogens, such as anthrax, smallpox, ricin and botulinum toxin. The approach could simultaneously identify multiple pathogens via their unique fluorescent characteristics.
Another detection strategy involves the development of electrical current-based readout of the nanowires for protein and virus sensing. The wires are arranged as field-effect transistors (FETs), where slight variations at the surface produce a change in conductivity. Developers of this technology predict that a high-density nanowire-circuit array geared toward pathogen detection could be built on a large scale suitable for biosecurity surveillance.
Physical, chemical and optical properties that can be tuned to detect a particular bioagent are key to microbead-based immunoassay sensing systems. A unique spectral signature or fingerprint can be tied to each type of bead. Beads have been joined with antibodies to specific biowarfare agents. This method has been demonstrated in the Autonomous Pathogen Detection System (APDS), a technology developed by Lawrence Livermore researchers. APDS contains an aerosol collector to constantly “inhale” particles from its surrounding environment for analysis.
Microarray-based immunoassay sensing approaches can be used to detect bacteria, such as the E. coli recently found in spinach and other fresh-packed greens. This approach can differentiate pathogens from harmless bacteria. In an analogous technique called aptamer microarray, short single strand chains of DNA (less than 100 nucleotides) are developed that bind to target molecules and fold into complex structures. The folding event results in an easy-to-read electrical charge. This binding-induced signaling strategy is particularly well suited for sensing in complex samples.
In a whole-cell-based immunoassay sensing system, an engineered B lymphocyte cell in which both pathogen-sensing membrane-bound antibodies and an associated light-emitting reporting system are all expressed in vivo. The B lymphocyte cell-based sensing system, termed CANARY, centers on an easily expressed calcium-sensitive bioluminescent protein from the Aequoria victoria jellyfish. When exposed to targeted biowarfare compounds, an increase in photons was observed within the B lymphocyte cells in a matter of seconds. The photon changes can then be easily detected using an inexpensive optical system.
“The ability to miniaturize and adapt traditional bench-top immunoassay protocols to a fully automated micro-or nano-fluidic chip holds tremendous promise to enable multiplex, efficient, cost-effective and accurate pathogen sensing systems for both biodefense and medical applications,” Tok said.
Anne Stark | EurekAlert!
Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology
Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences