Pill sized heater could help diagnose diseases

A pill sized ‘heater’ could allow resource-limited regions to test for infectious diseases without the need for specialised training or costly lab equipment.

pill sized heater
Buddhisha Udugama (left) and Pranav Kadhiresan (right) hold a miniaturised lithium heater (Image: Qin Dai / University of Toronto Engineering)

This is the claim of a team from University of Toronto Engineering whose technology regulates the temperature of biological samples through different stages of diagnostic testing, which is crucial to the accuracy of test results.

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“The precision and flexibility of our heater opens the door to a future of do-it-yourself diagnostic kits,” says PhD candidate Pranav Kadhiresan, who developed the device alongside PhD candidate Buddhisha Udugama, under the supervision of Professor Warren Chan.

“We could combine the simplicity of a high school chemistry set with the precision of cutting-edge lab instruments,” Kadhiresan said in a statement. The technology behind the team’s miniaturised heater is described in Proceedings of the National Academy of Sciences (PNAS).

According to the university, multiple temperature-regulation steps are involved when carrying out diagnostic tests for infectious pathogens. The ability to control temperature is especially important in areas where access to large research facilities are limited.

“The lack of electricity adds a layer of complexity,” Udugama said. “Our miniature heater addresses that. It can be used in various settings to detect viruses without the need for electricity. If we were to summarise the benefits of our technology, it would be accessibility, portability and precision.”

The outside of the heater tablet is composed of a non-reactive acrylic mould that encapsulates lithium. When dissolved in water, lithium releases heat and hydrogen gas, leading to an increase of temperature for an extended period of time.

The researchers observed that the reproducibility of the temperature profile is controlled by constant gas release, which is dictated by the shape of the lithium mould. After testing multiple shapes of the lithium mould – from circles to triangles – they found the star shape, measuring 8mm in diameter, to be the best for precise heating.

Consolidating multiple steps into a single pill sized heater tablet also means specialised training is not required to operate any diagnostic testing, reducing the chance of human error and making the device accessible to the public.

“Tablets are conventionally used for medications such as aspirins. But we have now developed a series of tablets and pills that can diagnose diseases,” said Chan. “Combined with smartphone technology, everyone would have a portable system that can track, monitor and diagnose infections. This is critical for preventing the spread of diseases.”