EN
In medical diagnostics, rapid detection of
pathogenic bacteria from body fluids is one of the basic issues.
Most state-of-the-art methods require optical labeling,
increasing the complexity, duration and cost of the
analysis. Therefore, there is a strong need for developing
selective sensory devices based on label-free techniques,
in order to increase the speed, and reduce the cost of detection.
In a recent paper, we have shown that an integrated
optical Mach-Zehnder interferometer, a highly sensitive
all-optical device made of a cheap photopolymer, can be
used as a powerful lab-on-a-chip tool for specific, labelfree
detection of proteins. By proper modifications of this
technique, our interferometric biosensor was combined
with a microfluidic system allowing the rapid and specific
detection of bacteria from solutions, having the surface of
the sensor functionalized by bacterium-specific antibodies.
The experiments proved that the biosensor was able
to detect Escherichia coli bacteria at concentrations of 106
cfu/ml within a few minutes, that makes our device an appropriate
tool for fast, label-free detection of bacteria from
body fluids such as urine or sputum. On the other hand,
possible applications of the device may not be restricted to
medical microbiology, since bacterial identification is an
important task in microbial forensics, criminal investigations,
bio-terrorism threats and in environmental studies,
as well.