Wouldn’t you want to know what kinds of bacteria are floating in your operating room? Indeed, detection and identification of microorganisms in ambient air can be useful for clinical and food processing facilities. A collaboration of scientists from six Fraunhofer Institutes has developed a prototype system that can perform an air test within thirty minutes.
“We take a plastic chip and apply a gel to it. We embed special fluorescent-marked antibodies in this gel. These detect very specific microorganisms which can then be viewed under a fluorescence microscope,” explains Gerd Sulz, project manager at the Fraunhofer Institute for Physical Measurement Techniques IPM in Freiburg. The test system monitors the ambient air by accumulating different microorganisms and particles – including dust – on the gel, and segregating only particles between one and ten micrometers in size. The antibodies in the gel bind to specific microorganisms, which fit into them like a key in a lock. They do not bind to specks of dust or other germs. The task of the Freiburg scientists is to detect the identified microorganisms using an optical technique. The first step is a wash cycle that removes all the antibodies not bound to microorganisms. This is done by applying an electrical voltage – the unbound antibodies are so small that they can be moved through the gel by the electric field, whilst the antibodies that have latched onto a microorganism remain trapped. A glance at the chip reveals whether any antibodies, and how many, have bound to microorganisms – the trapped antibodies glow red due to the fluorescent marking. The result provides information about the type and number of potentially dangerous microorganisms in the air.
Full story: Chip detects microorganisms in ambient air….
Image: The fluorescent marking of the antibody causes the bound test particles — which fit like a key in a lock — to emit a red glow.
