A Montreal-based startup is developing self-powered microfluidic chips that depend on capillary action to direct the flow of fluid, time the reactions, and switch between liquids. Sensoreal’s highly sensitive yet inexpensive biosensor prototypes are designed to help doctors quickly diagnose their patients with point-of-care blood tests using immunoassays that measure the presence of antibodies or other markers.
Sensoreal Inc. is a spin-off from McGill University where the company’s founder, Roozbeh Safavieh, is nearing completion of his doctorate under the supervision of Dr. David Juncker, Canada Research Chair in Micro- and Nanobioengineering. The research group focuses on miniaturizing biological experimentation to microscopic scales.
“Miniaturization of fluidic devices is useful because it allows us to work with smaller reagent volumes, thus reducing the cost of analysis, enabling parallel operations, and decreasing reaction times by increasing the surface-to-volume ratio and accelerating mass transfer limited reactions,” says Safavieh.
One of Sensoreal’s breakthrough technologies could help doctors more quickly diagnose patients with heart attack symptoms. Instead of sending a patient’s blood to a lab and waiting for results to confirm the presence of biomarkers associated with damage to the heart, the test could be done in the emergency room. A second application, which has also been patented, would allow health care professionals to quickly determine if a patient is carrying troublesome Methicillin-resistant Staphylococcus aureus (MRSA), which can cause serious complications after surgery.
The microfluidic platforms are essentially tiny chemistry laboratories with embedded channels that direct the flow of fluid to sensors and reagents that determine whether a particular protein or antibody is present. But unlike other microfluidic chips, Sensoreal’s approach doesn’t require external pumps or outside sources of energy to move the fluid through the channels. Instead, they rely on capillary action—the same phenomenon at work when you place a straw in a glass of juice—where the smaller the diameter of the capillary tube, the greater the effect. And, in Sensoreal’s chips, the valves and pumps are made from hydrophilic materials, which attract water.
With the help of design software provided by CMC Microsystems, the company has produced microfluidic chips that Safavieh indicates are highly sensitive and also inexpensive, costing between $1 and $3 with a reader priced between $10 and $30. Currently, readers used with microfluidic diagnostic chips can cost several thousand dollars since they require pumps to keep the fluid moving. With the capillary action, the fluid flows through the Sensoreal chips on its own.
They hope to apply for approval from the Food and Drug Administration in the United States within a year.
Operating in a mode of continual experimentation and discovery, Safavieh and his colleagues are now developing a prototype for making a point-of-care device to detect iron deficiency. They have also patented a microfluidic chip that uses inexpensive yarn instead of micro-channels. That idea came to him when he was drinking a cup of tea, and watched the dark fluid move up the string of the tea bag. “That’s something we will look at in the future.”