Infectious diseases such as malaria and syphilis can be diagnosed rapidly and reliably in the field by using a simple test developed by Canadian scientists. The test is based on the use of DNAzymes and gold nanoparticles. As the researchers report in the journal Angewandte Chemie, their test allows for the sensitive detection of bacteria, viruses, and parasites.
Dangerous infectious diseases must be identified in time in order to prevent them from spreading. The DNA of pathogens is an ideal biomarker and can easily be identified by PCR. However, this is only possible if expensive laboratory equipment and trained personnel are on hand. This may not be the case in remote locations or developing nations. Alternative methods that are simple and inexpensive while also remaining sensitive and specific are needed.
Kyryl Zagorovsky and Warren C.W. Chan at the University of Toronto (Canada) have now combined two modern technologies in a novel way: They have used DNAzymes as signal amplifiers and gold nanoparticles for detection. Gold nanoparticles (GNPs) absorb light. The wavelength of the light absorbed depends on whether the nanoparticles are separate or aggregated. The difference in color can be seen with the naked eye. A solution of individual particles appears red, whereas aggregates are blue-violet in color.
DNAzymes are synthetic DNA molecules that can enzymatically split other nucleic acid molecules. The researchers separated a DNAzyme into two inactive halves that both selectively bind to a specific gene segment of the pathogen to be detected. The act of binding reunites the halves and activates them.
For their test procedure, the scientists produced two sets of GNPs that bind to two different types of DNA strand, type A and type B. In addition, they synthesized a three-part “linker” made of DNA. One end of the linker is the complement to type A DNA; the second end is the complement to type B DNA. The center part is designed to be split by active DNAzymes.In the test sample with no pathogen present, the DNAzymes remain inactive and the linkers remain intact. They bind to a GNP at each end and link the GNPs into larger aggregates, causing the solution to turn blue-violet. In contrast, if there is pathogen in the sample, the DNAzymes are activated and proceed to split the linkers. Now only the bridging parts of the linker can bind to DNA strands of the GNPs, so they cannot link the GNPs together. The solution stays red. Because every activated DNAzyme splits many linkers, it amplifies the signal.
For the full article see https://www.wiley-vch.de/vch/journals/2001/journalist/201305pre.pdf (editorial use only).About the Author
Title: A Plasmonic DNAzyme Strategy for Point-of-Care Genetic Detection of Infectious Pathogens
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201208715
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Trade Fair News
16.01.2017 | Automotive Engineering
16.01.2017 | Life Sciences