Is it drugs, medicines or explosives? At the analytica trade fair, Fraunhofer researchers, joined by the Hübner Company, are presenting a terahertz spectrometer that provides reliable, contact-free identification of substances. December 2011: Security forces intercept a letter bomb addresse ... more
Point-of-care diagnostics: New methods for detecting single molecules
Pathogen-specific detection: Even one single DNA molecule is enough
Resistance to antibiotics is on the rise worldwide. Researchers at the Fraunhofer Institute for Physical Measurement Techniques IPM alongside the Ludwig Maximilian University of Munich have developed a process for rapidly detecting multidrug-resistant pathogens. The unique feature: Even one single molecule of DNA is sufficient for pathogen detection. In future, the platform could be introduced as part of point-of-care diagnostics on hospital wards or in medical practices as an alternative to the established PCR analyses or in combination with other diagnostic methods.
Choosing the correct antibiotic to treat bacterial infections is a deciding factor when it comes to the success of a treatment. It is particularly difficult to select suitable medication in cases where a disease is caused by multidrug-resistant pathogens, which are unaffected by many antibiotics. Searching for the most effective antibiotic often requires information about the bacteria’s genome. Most of the time, this information is not readily available at medical practices and can only be obtained through a laboratory diagnosis. To accelerate and simplify the process, Fraunhofer IPM has collaborated with the Ludwig Maximilian University of Munich to develop a new platform for detecting pathogens on the basis of single molecules on a microfluidic chip. The focus of the SiBoF (signal boosters for fluorescence assays in molecular diagnostics) project lies on an easy-to-use point-of-care (POC) detection method. The project is funded by the German Federal Ministry of Education and Research (BMBF).
Pathogen-specific detection based on DNA molecules
The portable, compact test platform is equipped with an automated fluidic system. All necessary reagents are stored within the system. The injection-molded microfluidic chip is incorporated in a drawer in the test system, where it is supplied with the reagents through the fluidics system before the optical analysis takes place. “We detect part of the pathogen’s DNA strand. Using our new process, even a single molecule of DNA that binds to a specific site on the microfluidic chip is sufficient to do this. Fluidic channels are integrated into the chip – the surfaces of which are primed with binding sites for specific pathogens,” explains Dr. Benedikt Hauer, scientist at Fraunhofer IPM.
Nanoantennas strengthen fluorescence signals
Typically, target DNA molecules are detected by means of specific fluorescence markers. A unique feature of the new method designed by Fraunhofer IPM and the Ludwig Maximilian University of Munich is that researchers are utilizing antennas with nanometer-sized beads, which amplify the optical signals of these markers. Because of this, chemical amplification via polymerase chain reaction (PCR) is not required. “The optical antennas consist of nanometer-sized metal particles that concentrate light in a tiny region and also help to emit the light – much as macroscopic antennas do with radio waves,” says Hauer, the project manager of this research project at Fraunhofer IPM. These metal particles are chemically bound to the surface of the chip.
Results available after one hour
A structure of DNA molecules, known as “DNA origami”, which was specifically designed by the Ludwig Maximilian University of Munich, holds both of the gold nanoparticles in place. Between these nanoparticles, the structure provides a binding site for the respective target molecule and a fluorescence marker. This patented design provides the basis for the novel assay technology. “The particles, which are 100 nanometers in size, serve as antennas. Field enhancement, caused by plasmonic effects, takes place in the hotspot between the two gold particles. If a fluorescent dye is placed there, the detectable long-wave fluorescence radiation is enhanced multiple times. Using this method, a single molecule can be detected using a small, compact optical device,” explains the researcher. Low concentrations of pathogens can be detected. The result is available after one hour and is displayed on the monitor. This is not only true for multidrug-resistant pathogens, but also for any type of DNA molecule. In principle, the single molecule assay can be adapted to molecules beyond DNA, such as RNA, antibodies, antigens or enzymes. Numerous tests have successfully confirmed the functionality of the process.
At the heart of the POC device is a miniaturized high-resolution fluorescence microscope, developed by Fraunhofer IPM. Specifically developed image analysis software identifies single molecules and by doing so enables the captured target molecules to be counted, providing a quantitative result. The fluorescence is stimulated using LEDs, which are affixed underneath the cartridge containing the fluidic channels.
The patented system is available for the purpose of demonstration. Currently, a module for sample preparation is still missing.
The human genome has been decoded. Of all the puzzles it contains, though, many remain unsolved. We know that the genome provides the blueprint for various proteins, the building blocks of each and every cell. But what role do they play? Which proteins control cell division in a healthy bod ... more
The safety and quality in the food supply of today’s globally organized and networked supply chain is everything else than warranted. More than 50% of all foodstuffs are spoiled in the transport routes; alone in Great Britain this makes up 17 million tons and approximately 20 billion Euros. ... more
What happens when we breathe in nanoparticles emitted by a laser printer, for example? Could these nanoparticles damage the respiratory tract or perhaps even other organs? To answer these questions, Fraunhofer researchers are developing the “NanoCube” exposure device. The Nanocube’s integra ... more
COVID 19 has turned PCR and other antigen tests from tools known only to medical professionals into an everyday experience for all of us. To mark the successful completion of their research on the PoC-BoSens platform, the project consortium led by Fraunhofer IZM can announce the birth of a ... more
A new high-performance white-light laser is expected to speed up quality control in the semiconductor industry and provide closer monitoring of toxicity tests in microbiology. In one step, this laser enables the two-sided characterization of surfaces and can be integrated into production ch ... more
Digitalization and artificial intelligence are changing diagnostics in clinical routine and pharmaceutical research. New IVD devices are coming out, laboratory data is connected to the hospital IT system and AI-based image analysis enables new and efficient processes in digital pathology an ... more
At Fraunhofer IZI-BB we develop analytical and biotechnological solutions for medical issues, animal health, food, cosmetics and the environment. Our research focuses on sample preparation, development of molecular recognition elements and data acquisition as well as miniaturization and aut ... more
When light impinges on molecules, it is absorbed and re-emitted. Advances in ultrafast laser technology have steadily improved the level of detail in studies of such light-matter interactions. FRS, a laser spectroscopy method in which the electric field of laser pulses repeating millions of ... more
In the Middle Ages, every city had its own system of measurement. Even today, you can sometimes find iron rods in marketplaces that determined the length measurement valid for the city at that time. In science, however, there is no room for such uncertainties, and no matter what method you ... more
Scientists from Hamburg and Munich developed the world's most powerful dual-comb spectrometer that paves the way for many applications in atmospheric science and biomedical diagnostics, such as early cancer detection. The work has recently been published in Nature Communications. The core p ... more
- 1Can the AI driving ChatGPT help to detect early signs of Alzheimer's disease?
- 2Simple nasal swab can provide early warning of emerging viruses
- 3Holes in T cells
- 4Molecular archeology: 1200-year-old DNA sequences from Madagascar lead to the discovery of an extinct tortoise
- 5Bruker Announces Acquisition of ACQUIFER Imaging GmbH
- 6How old is your brain, really?
- 7The architecture of shattered genomes
- 8Bayesian inference massively cuts time of X-ray fluorescence analysis!
- 9AI detects rare forms of dementia
- 10Texas A&M research aims to improve Lyme disease diagnostics