An interdisciplinary team of engineering and pharmaceutical researchers at the University of Alberta has invented a device that can rapidly identify harmful bacteria and determine whether they are resistant to antibiotics.1
The device could save precious hours in patient care and public health, and prevent the spread of drug-resistant strains of bacteria. Relying on nanoscale technology for fast results, the microscopic device was designed to look for and trap different types of bacteria, then find out which antibiotics are most effective against them.
(From left to right): Faheem Khan, PhD, Hashem Etayash, and Thomas Thundat, PhD. Photo credit: UAlberta Engineering.
The main feature of the device is a cantilever—a plank that resembles a diving board—with a microfluidic channel just one twenty-fifth the width of a hair etched on its surface. The channel is coated with biomaterials, such as antibodies, to which harmful bacteria such as E. coli or listeria in fluid samples bind.
When bacteria are caught, the device sends out three different signals to researchers.
When bacteria are detected, the cantilever’s mass changes, and it bends, explains Thomas Thundat, PhD, professor of chemical and materials engineering and the Canada Excellence Research chair in oil sands molecular engineering at the University of Alberta. “So this gives us two signals: the mass change and the bending action.”
By shining infrared light on the bacteria, a third signal is sent, he adds. If the bacteria absorb the light, the cantilever begins to vibrate, generating a minute amount of heat that sends a confirmation signal. Receiving a signal from all three detection methods “means there is no ambiguity,” Thundat says.
“By monitoring the interaction of light and bacteria, we can get highly selective detection of bacteria,” says Faheem Khan, PhD, a researcher in Thundat’s lab. “It’s our moment of truth.”
With the bacteria trapped in the cantilever, different antibiotic drugs can be added to the device. Changes in the intensity of tiny oscillations of the cantilever signal to researchers whether the bacteria are alive or dead, informing researchers about the susceptibility of the bacteria to specific antibiotics.
“We’re trying to find a way to fight bacterial resistance to drugs and prevent or at least decrease the spread of drug-resistant strains,” says Hashem Etayash, a doctoral student in the faculty of pharmacy and pharmaceutical sciences. “We’re able to do several tests in a very short period of time, and we can quickly identify bugs that can resist antibiotics.”
The device can be used to test extremely small fluid samples, on the order of one-millionth the size of a rain droplet. Thundat says the size of the device is advantageous for using small samples in such settings as a neonatal intensive care unit, or in situations where only very small samples are available.
The research was funded through the government of Canada’s Canada Excellence Research Chairs program. The team has patented the technology, and Etayash and Khan are hoping to design a handheld prototype of the device and bring it to market.
REFERENCE
- Etayash H, Khan MF, Kaur K, et al. Microfluidic cantilever detects bacteria and measures their susceptibility to antibiotics in small confined volumes. Nat. Commun. 2016;7:12947; doi: 10.1038/ncomms12947.
