By Canadian Press

Lab-on-a-chip test could help prevent disease outbreaks in remote regions: Study

Apr 25, 2018 | 3:05 PM

TORONTO — Canadian researchers have created a low-cost, portable device that can quickly test people to determine if they’re at risk for measles or rubella in parts of the world without access to standard laboratories, with the ultimate goal of preventing outbreaks of the deadly or disabling infectious diseases.

The MR Box, so called by its University of Toronto designers for measles and rubella, allows for on-the-spot assessment of a person’s vulnerability to these vaccine-preventable diseases, which remain a major scourge in developing countries worldwide.

Each year, measles causes an estimated 134,000 deaths and rubella leaves about 100,000 children with birth defects such as deafness.

At the heart of the shoebox-sized device is an inkjet-printed cartridge that uses the science of microfluidics to detect whether a child or adult has antibodies to measles or rubella in a pin-prick drop of their blood, indicating whether they have been exposed to either of the viruses through previous infection or vaccination.

A microfluidic device manipulates tiny amounts of fluid, such as blood, on a microchip to perform certain laboratory tests.

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“In essence, this type of device can serve as a ‘lab-on-a-chip’ that recapitulates the functions of a modern chemical laboratory in a package that can fit in the palm of the hand,” said principal researcher Aaron Wheeler, a professor of bioanalytical chemistry.

The test can process multiple blood samples at one time and produce results in 35 minutes, doing away with the need for collecting vials of blood that must be kept in cold-storage and transported to an often-distant laboratory for testing — a process that is both costly and time-consuming.  

Such rapid results would allow health authorities to quickly determine the risk of measles or rubella outbreaks in a population, such as displaced persons in refugee camps or among those living in remote areas, as well as help evaluate the effectiveness of immunization programs against those diseases.

The device is also inexpensive, a boon for developing countries with often inadequately funded health-care systems, the authors suggest.

Darius Rackus, a postdoctoral researcher in Wheeler’s group, said the cartridges cost about $6 each to produce, but by commercially scaling up the manufacturing process, “hundreds of thousands of these devices” could be printed, potentially one day bringing the cost down to “pennies each.”

The scientists, whose work is featured as the cover story in Wednesday’s issue of the journal Science Translational Medicine, tested the MR Box in the Kakuma refugee camp in Kenya in the spring of 2016.

Working with international partners, including researchers at the U.S. Centers for Disease Control (CDC), members of Wheeler’s lab travelled to Kenya, where they used the MR Box to test blood samples from 144 children and their caregivers in the refugee camp for the presence of antibodies to measles and rubella.

The team also collected standard blood samples from the participants, which were sent for testing to Kenya’s national laboratory in Nairobi for comparison.

“The overall agreement with the reference test was 86 per cent for measles and 84 per cent for rubella,” said Julian Lamanna, a PhD candidate in Wheeler’s lab and a member of the team that travelled to Kenya.

“These results are really quite exciting considering that this was the first time that we took our instrument and test outside of the lab,” Lamanna told a media teleconference, noting that the on-the-ground trial was extremely challenging, due to a small transformer fire, sporadic power outages and a batch of chemicals used in the MR Box testing that was spoiled. 

“But through this field trial, we were able to translate our research to the real world,” he said.

Aimee Summers, an epidemiologist at the CDC who was part of the Kenya team and a co-author of the research paper, said use of the MR Box “could help to inform a need for vaccination campaigns in these settings” by determining if people already have immunity to the viruses or need to be inoculated. 

“Effective immunization systems can reduce illness and death from vaccine-preventable diseases and help limit the magnitude and number of infectious disease outbreaks,” she said.

But the device could also be designed to go beyond testing for antibodies to measles and rubella, said Wheeler, whose lab is working on tests for detecting malaria and the Zika virus.

“We chose measles and rubella because that happened to be an assay that we were working on and that happened to be a very important set of infectious diseases in areas where there isn’t good vaccinations,” he said.

“But it’s a platform technology … there are many more tests than we have the manpower or financial resources to develop, but that is the dream, that this type of system with its flexibility could be sent out into the world and really used very flexibly depending on the conditions on the ground.”

— Follow @SherylUbelacker on Twitter.

Sheryl Ubelacker, The Canadian Press