Detecting pathogens with magnetic fields

Using magnetic fields to detect pathogens is a new technique for American scientists. According to the research team, this method has a very high sensitivity and can detect many different pathogens in the same test piece.

The research team at Purdue University and Duke University is developing a technique to use rotating magnetic fields to simultaneously detect many 'pathogens' - pathogens, specifically pathogens, especially microorganisms. live like bacteria, viruses or fungi.

According to this technique, when placed in a rotating magnetic field, magnetic particles that carry antibodies will attract the pathogens present in the sample, and once finished, these particles will be separated. It depends on their size and the speed of the magnetic field.

Professor Gil Lee, Purdue University's chemical and biomedical engineering expert, explains: ' Magnetic particles in microseconds (1 millionth of a meter) will be surrounded by antibodies. able to identify certain pathogens. And these particles are dispersed in a patient's blood sample . '

US scientists are developing techniques to use rotating magnetic fields to simultaneously detect many pathogens
in the same sample. ( Photo: .eng.ox.ac.uk )

These magnetic elements have a superparamagnetism, which means they only turn into a magnetic state when placed in a magnetic field. Therefore, when mixed into the test sample, they do not attract each other and form a block, but when the rotating magnetic field starts to operate, those particles become magnetized.

When the specimen contains magnetic particles that carry antibodies placed on the rotating magnetic field - created by a microchip (microprocessor circuit) containing tiny metal discs, 3 electromagnets and tools Other - the different pathogens present in the sample will be attracted by magnetic particles of different sizes.

Therefore, this new technique can selectively separate magnetic elements according to size , and thus can diagnose the presence of many possible pathogens in the same specimen.

Professor Lee further explained: ' When the rotating magnetic field operates at a certain speed, we will separate magnetic elements of certain sizes. Therefore, by changing the rotational speed of the magnetic field, we will separate the particles that sucked the pathogen from the rest of the sample . '

Experts call this new technique ' non-linear magnetophoretic separation '. The team said the technique has yielded good results in the past tests.

According to Dr. Hao Shang, of Purdue University, the advantage of this method is that it can simultaneously isolate and identify multiple pathogens, with sensitivity that can be 1 million times higher than the ' immunoassay ' method. 'solid phase immunoassays' (solid phase immunoassays) are being used today.

This research has just been introduced on the electronic edition of Lab on a Chip.

Quang Thinh