While the Canadian government has recently pledged $500M to immunize children in the world’s poorest countries, rapid, inexpensive detection and surveillance systems for deadly diseases is crucial for countries that can’t afford to vaccinate their entire populations. It’s a challenge that University of Toronto researchers are meeting with an ingenious twist: a paper-based diagnostic system. Awarded $112,000 by Grand Challenges Canada’s “Bold Ideas” initiative, the system is being touted for its potential impact on infant and maternal health in developing nations.
Professor Aaron Wheelerand his team of researchers (Institute of Biomaterials & Biomedical Engineering (IBBME), Dept. of Chemistry, Donnelly Centre) are developing a low-cost, portable system to detect measles and rubella infection status and immunity. Using a small machine called the DropBot, developed in the Wheeler Lab, researchers insert a thin strip of paper approximately 1 inch wide by 3 inches long into a testing platform, across which they digitally manipulate droplets of sample. Printed for less than a dollar by a standard ink jet printer in a circuit-like design, the paper is an elaborate system that, as a by-product of a process involving magnetic beads, reagents, and patient samples, generates light. The brightness of the light emitted indicates recent infection or immunity to measles or rubella. With just one droplet of blood, four concurrent tests can be carried out within thirty-five minutes.
In some of the world’s poorest nations, though, thirty-five minutes could have life-changing impact.
“Every hour 11 infants are born with congenital rubella syndrome (CRS) and 18 children die of measles,” says Alphonsus Ng (PhD Candidate 1T5), one of the lead designers of the technology.
“Vaccinating children is great,” explains Ng. “But the entire population still needs to be monitored, because there will still be vulnerable segments of the population, and that can lead to serious health risks.”
While rubella – sometimes referred to as “German measles” – has comparatively milder symptoms than measles, the complications can be enormous – especially for pregnant women, who can pass on the disease to their unborn children with devastating effects – from severe developmental problems, to blindness and stillborn births. The WHO estimates that approximately 110,000 children are born with congenital rubella syndrome (CRS) every year – but that statistic does not account for the number of women who miscarry or experience other pregnancy-ending complications from the disease.
In the next eighteen months, the team plans to test their technology on 200 patient samples in Vietnam.
“Vietnam is a hotspot for measles and rubella because they don’t have a common rubella vaccination yet,“ says Ng.
It’s also a country in dire need of diagnostic resources: Vietnam has only two diagnostic labs, one in the south and one in the north. Introducing a rapid, economical field diagnostic tool could have an enormous impact on this country of 97 million, and lead to better-informed public health policies.
But testing the technology in the field will also allow the team to work on fine-tuning the technology specifically for the poorest nations.
“It costs us maybe a dollar to print the [paper] test chips,” explains Fobel, one of the masterminds behind the DropBot, “but printing these in an industrial setting would cut costs by another order of magnitude.” The team is also looking at ways to cut the cost of manufacturing the DropBot to a few hundred dollars, which would put the technology into far more hands, and potentially, allow everything to be manufactured within the host country, generating local jobs.
“This is a great opportunity to bring digital microfluidics out into the field to address a real world problem,” says Wheeler. “I am proud to be working with such a motivated, enthusiastic team.”