Our ability to detect pathogens has become quite good, but it usually requires complex laboratory techniques. Sometimes we need a quick result, or there is no laboratory nearby.
Portable and fast methods of detection that are also sensitive, reliable, quantitative, and effective over a broad range of concentrations are thus highly desirable. In the journal Angewandte Chemie, American researchers have now introduced a new approach for a lab-on-chip technique for the detection of pathogens by means of their genetic material. The method is so sensitive that it was able to detect as few as 16 copies of DNA from salmonella—in less than an hour.Since the introduction of the polymerase chain reaction (PCR)—which has become the primary method for the duplication of genetic material—into clinical diagnosis, the detection of many pathogens has become significantly more reliable and sensitive. However, even PCR requires a great deal of equipment and time, involving bulky apparatus, precisely maintained temperature cycles, and successive addition of reagents. All of this demands a certain expertise from the operator.
In a tiny chamber on the chip, enzymes generate copies of the DNA contained in the sample. Six different primers, single-stranded fragments of the target DNA with a start sequence for the enzymes, act as the starting point. Methylene blue, a dye that lodges in DNA strands, serves as the electrochemical detection reagent. At first, most of the methylene blue molecules are free in the solution and come into contact with electrodes that are mounted in the chamber.When a cyclic voltage is applied, redox reactions between the electrode and the methylene blue produce a current. The more copies of the DNA that are produced, the more methylene blue is lodged in the strands, making it unavailable to the electrodes, thus causing the current to decrease. This goes faster when more pathogenic DNA strands are contained in the sample. The time at which the current signal is at its maximum can be determined so accurately that the researchers can use it to quantify the concentration of pathogen.
A future chip could support multiple chambers for the parallel detection of different pathogens. This could then be used as a prototype for the development of effective rapid tests for point-of-care diagnosis, food safety, environmental monitoring, and the fight against biological weapons.
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201109115
Dissolving protein traffic jam at the entrance of mitochondria
23.05.2019 | Albert-Ludwigs-Universität Freiburg im Breisgau
Producing tissue and organs through lithography
23.05.2019 | Goethe-Universität Frankfurt am Main
Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.
The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...
Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...
With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.
Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...
'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.
However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...
Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future
When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
23.05.2019 | Materials Sciences
23.05.2019 | Materials Sciences
23.05.2019 | Physics and Astronomy