IBM researchers speed up medical diagnostic testing via chip
IBM researchers have cooked up a quick medical diagnostic testing system based on a silicon chip that can get by on small sample and test for multiple diseases.
The breakthrough to be announced Tuesday means that physicians can test a patient immediately following a heart attack to improve survival rates. The test checks for disease markers, proteins that can be detected in blood using "capillary action force." In a nutshell, capillary forces refer to the tendency of a liquid to rise in narrow tubes or be drawn into a small opening. The IBM Research-Zurich findings will be detailed in the December issue of the Royal Society of Chemistry (see reprint PDF).
Big Blue's chip measures 1 x 5 centimeters and contains sets of micrometer wide channels where a test sample would flow for 15 seconds. The filling speed of the fluid being tested can be adjusted if the chip needs extra time to read a disease marker. Here's how the chip works in stages:
- First, a one microliter sample, 50 times smaller than a tear drop, is pipetted onto the chip, where the capillary forces begin to take effect...
- Then these forces push the sample through an intricate series of mesh structures...
- The sample then passes in a region where microscopically small amounts of the detection antibody have been deposited. These antibodies have a fluorescent tag and are attached within the sample...
- In the reaction chamber, which is about the diameter of a human hair, captures the previously tagged marker. Under a red beam of light, the disease markers can be viewed using a portable sensor device that contains a chip similar to those used by digital cameras. Medical professionals can visually confirm the strength of the disease marker.
The linchpin to this process is the capillary pump, a series of microstructures about 180 micrometers deep. The pump pushes through enough of the sample to create a regular flow rate and make the test accurate.
IBM added that the chip is designed for multiple form factors.