A team of New York-based researchers at Columbia University and Columbia Engineering have utilized computer-type circuitry to study bacteria.
Integrated circuit technology is the basis of computers and modern cell phones but the Columbia team has developed a new kind of chip using "complementary metal-oxide-semiconductor" (CMOS) technology. This technology, they claim, allows the chips to "listen" to bacteria.
The intention of the researchers it to understand how "biofilms" form. Biofilms are complex communities of microbial cells that grow together on living or inert surfaces. Experts estimate that 60-80% of microbial infections in humans are caused by biofilm bacteria.
"Disrupting biofilm formation has important implications in public health in reducing infection rates," says study leader Ken Shepard, professor of electrical engineering and biomedical engineering at Columbia Engineering. "This is an exciting new application for CMOS technology that will provide new insights into how biofilms form."
How does the technology improve on existing techniques for studying bacteria?
The chip is a solid support for the bacterial colony, but it also responds directly to molecular changes in the bacteria growing on it.
Microscopy techniques are normally used to study biological systems.
Photons (particles of electromagnetic energy) can be used to perform "relatively non-invasive" interactions with the biological system being studied, but these techniques cannot detect primary metabolism or signaling factors, which are important components of physiology.
The integrated circuit chip that the team developed is referred to by Shepard as an 'active glass slide' - it is a solid support for the bacterial colony, but it also responds directly to molecular changes in the bacteria growing on it.
"This is a big step forward," says Lars Dietrich, assistant professor of biological sciences at Columbia University. "We describe using this chip to 'listen in' on conversations taking place in biofilms, but we are also proposing to use it to interrupt these conversations and thereby disrupt the biofilm."
"In addition to the pure science implications of these studies, a potential application of this would be to integrate such chips into medical devices that are common sites of biofilm formation, such as catheters, and then use the chips to limit bacterial colonization."
The part of the bacterial "conversation" that the team are listening in on specifically involves a type of molecule - called phenazines - that are secreted by the cells of the bacteria when physiological activity occurs.
It is thought that these phenazines contribute to the growth of bacteria colonies, so by listening for these molecules, a modified chip may also be able to interfere with the spread of the colony.
"This represents a new and exciting way in which solid-state electronics can be used to study biological systems," Shepard adds. "This is one of the many emerging ways integrated circuit technology is having impact in biotechnology and the life sciences."
Other studies into the medical implications of biofilms have in recent years looked at the resistance of salmonella biofilms to powerful disinfectants and how research into "hyperswarming" bacteria could produce anti-biofilm treatments.
Written by David McNamee