IBM creates rapid diagnostic testing system on a chip
18 November 2009
Researchers at IBM's Zurich labs have created a
point-of-care diagnostic test system based on microfluidics on a
silicon chip. The lab-on-a-chip requires less sample volume, is
significantly faster, portable, easy to use and can test for many
The system analyzes tiny samples of blood for the presence of disease
markers, which are typically proteins. Specific antibodies with a
fluorescent tag bind to the disease marker and are then captured in a
special chamber on the chip where they can be detected using a focused
beam of light.
The device was developed using IBM's expertise in silicon chip
technology, surface chemistry, and nanotechnology.
The results are so quick and accurate that a patient’s serum or blood
sample could be tested immediately following a heart attack, to enable
the doctor to quickly take a course of action and to predict the
patients survival rate.
IBM Research - Zurich scientists Luc Gervais and Emmanuel Delamarche,
in collaboration with the University Hospital of Basel in Switzerland,
have developed the new lab-on-a-chip.
"This point of care test has achieved the trifecta for medical staff
in that it is portable, fast and requires a very small volume of
sample," comments Emmanuel Delamarche, scientist, IBM Research — Zurich.
"We are giving back precious minutes to doctors so they can make
informed and accurate decisions right at the time they need them most to
All in the chip
The chip, which measures 1 × 5 cms, contains sets of
micrometer wide channels where the test sample flows through by
capillary action in
approximately 15 seconds, several times faster then traditional tests.
Uniquely, the filling speed can be adjusted to several minutes by using
different microfluidic designs, when additional time is needed to read a more complex disease marker.
The diagnostics system consists of five innovative stages:
Stage 1: A one microliter sample, 50 times smaller than a tear
drop, is pipetted onto the chip, where the capillary forces begin to
Stage 2: These forces push the sample through an intricate series of
mesh structures, which prevent clogging and air bubbles from forming;
Stage 3: 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 similar to the antibodies within
our body, they recognize the disease marker and attach to it within the
sample. Only seventy picoliters (a volume one million times smaller than
a tear) of these antibodies are used, making their dissolution in the
passing sample extremely fast and efficient.
Stage 4: The most critical stage is called the "reaction chamber" and
it measures 30 micrometers in width and 20 micrometers in depth, roughly
the diameter of a strand of human hair. Similar to a common pregnancy
test, in this stage the disease marker that was previously tagged is
captured on the surface of the chamber. By shining a focused beam of red
light, the tagged disease markers can be viewed using a portable sensor
device that contains a chip similar to those used by digital cameras,
albeit this one being much more sensitive. Based on the amount of light
detected, medical professionals can visually confirm the strength of the
disease marker in the sample to determine the next course of treatment.
Stage 5: Less a stage and more a part of the entire process is the
capillary pump. The capillary pump, which has a depth of 180
micrometers, contains an intricate set of microstructures, the job of
which is to pump the sample through the device for as long as needed and
at a regular flow rate, just like the human heart. This pump makes the
test accurate, portable and simple to use. IBM scientists have developed
a library of capillary pumps so that tests needing a variety of sample
volumes or test times can still be done without having to re-engineer
the entire chip.
Going to market
True to IBM's strategy of open collaboration, scientists in Zurich
followed a “bench to bedside” strategy where ideas from their lab were
tested with academic and healthcare partners. This research also would
not have been possible without the generous support of KTI/CTI, an
organization which fosters innovation in Switzerland.
"This microfluidic chip is the next step in the evolution of point of
care devices. We look forward to working with the scientists at IBM
Research - Zurich to develop this innovation even further," said Thierry
Leclipteux, Chief Executive Officer and Chief Science Officer, Coris
IBM scientists designed the chip with flexibility in mind in both its
form and uses. Due to its small size the chip can be embedded in several
types of form factors, depending on the application, including a credit
card, a pen or something similar to a pregnancy test. Besides diagnosing
diseases, the test is also flexible enough to test for chemical and bio