Credit card-sized diagnostic platform provides fast sepsis test
By Grant Banks
December 20, 2010
A fast and easy test for sepsis, or blood poisoning as it is commonly known, has been developed by researchers at the Fraunhofer Institute for Cell Therapy and Immunology, Germany. The credit card-sized diagnostics platform called MinoLab uses magnetic nanoparticles to provide a diagnosis in a fraction of the time of current test and without samples having to be sent to a pathology lab. It might also prove useful for identifying genetic predispositions and diagnosing cancer.
The lengthy diagnosis time associated with current procedures has contributed to sepsis being listed as a top-ten cause of death in the U.S and third most frequent cause of death in Germany, where the test was developed. The Sepsis Nexus of Expertise claims that patients arriving at the intensive care ward with blood poisoning only have a 50 percent chance of survival. A main reason for this high mortality rate is late diagnosis, with current procedures taking as much as two days to perform.
The new diagnostic platform is about as big as a credit card and takes about an hour from needle to diagnosis. It uses Sepsis cell targeting nanoparticles that bind with pathogen DNA. Using magnetic forces the Sepsis cells are guided into a detection chamber where a magnetoresistive biochip can detect pathogens and antibiotics resistance.
“After taking a sample of blood, magnetic nanoparticles bind themselves to the target cells in the blood sample through specific catcher molecules,” Dr Dirk Kuhlmeier, a scientist at the Fraunhofer Institute for Cell Therapy and Immunology said. “We then use a simple magnet to transfer the particles onto the plastic card along with the pathogens and move them through various miniaturized reaction chambers which is where the polymerase chain reaction takes place. This is a method for copying even the smallest DNA sequences of pathogens millions of times. After it is copied, the nanoparticles transport the pathogen DNA into the detection chamber where a new type of magnetoresistive biochip can identify pathogens and antibiotics resistances. All reactions starting from sample preparation through isolating the target molecules right down to documentation are carried out without any contact and fully automatically.”
The test is also said to reduce the risk of contamination providing false positives. The simple test might also prove to be more cost effective than the current pathology procedures. “We not only save time with the combination of magnetic nanoparticles in a new type of micro-fluid [but] miniaturization means we also save expensive apparatuses,” Dr Kuhlmeier said.
While the researchers have been successful at using magnetic nanoparticles to isolate and document the sepsis pathogens, it will be another two years until a prototype of the diagnostic platform will be seen. Once developed this technology may also be suited for a much wider range of medical tests. “It will be able to back up doctors in hospitals and private practices answering a wide range of molecular biological issues ranging from genetic predisposition right down to cancer diagnostics,” Dr Kuhlmeier said.
MinoLab is presently being developed at the Fraunhofer Institute for Cell Therapy and Immunology (IZI) in Leipzig, Germany in collaboration with Magna Diagnostics, a company hived off from the Fraunhofer Society under funding from the German Federal Ministry of Education and Research. Other project partners are the Fraunhofer Institute for Reliability and Microintegration (IZM) in Berlin as well as the companies Siemens, Dice, microfluidic Chip Shop and the Austrian Institute of Technology.