'Lab in a backpack' promises low-cost, accessible COVID testing

2022 01 22 00 59 2995 2022 01 26 Lab Backpack 400

A new proof-of-concept study tested a $51 "lab in a backpack" that promises to bring accessible, low-cost COVID-19 testing to anywhere in the world, according to research published on January 26 in PLOS One. The researchers hope that their model can be used to develop commercial tests for less than $15.

To mitigate the spread of COVID-19, testing remains the top priority after vaccination, which continues to be a challenge in resource-poor countries, where full vaccination is still two to three years away. In the meantime, ongoing COVID-19 testing is urgently needed.

"After vaccines, tests are the second-most important component in the fight against the pandemic," said the researchers, led by Emily Lin of Queen Mary University of London. "So far we have put up with the exorbitant prices of some of these quick turnaround tests, but it's time to open up the competition of ideas so we can reduce costs and make them more accessible."

End-to-end solution in resource-poor settings

Lin et al devised the "lab in a backpack" to address the testing needs of resource-poor regions. The backpack includes noninvasive saliva test samples that are processed using reverse transcription loop-mediated isothermal amplification (RT-LAMP), giving similar results to a polymerase chain reaction (PCR) test.

The $51 'lab in a backpack.' Image courtesy of Lin et al. Licensed under CC BY 4.0.The $51 "lab in a backpack." Image courtesy of Lin et al. Licensed under CC BY 4.0.

The system can process six samples in 90 minutes, has reagent costs of $3.50 per sample (commercial reagents cost $7 to $24), and is sensitive enough to detect as few as four viral RNA copies per microliter, according to the authors.

The system's instructions, which are highly graphical and designed for personnel with minimal training, guide users through the process of mixing the disposable reagent packs, which are numbered and color-coded.

Centrifuge built from recycled hard drives

The system includes an electronically operated centrifuge called CentriDrive, which can be assembled from recycled components at an approximate cost of $28.

The heart of CentriDrive is a recycled computer hard drive in which the head arm and plate have been dismantled, leaving just the motor, controls, and chassis. The technical specifications of a computer hard drive, specifically its balance and control over the speed of rotation, make it ideal for use as a diagnostic centrifuge, according to the researchers.

"Hard drives with rotating spindles are engineered so well that usually they are disposed with unwanted computers in working order," the authors observed, adding that the failure rate of hard drives in cloud computing farms, where they are used constantly, is only 1% to 2% per year on average.

"The centrifuge includes a 3D-printed rotor and a 12 V rechargeable Li-ion battery, and its 12 V standard also allows wiring directly to automobile batteries, to enable field-use of this and other tests in low infrastructure settings," the authors wrote.

Global COVID-19 testing

With portable and low-cost COVID-19 testing in mind, Lin et al said they devised the test to be suitable for at-home self-testing, field testing, or in mobile testing centers with lightly trained staff, even in difficult locations.

"The noninvasive nature of saliva testing would allow higher penetration of testing and wider adoption of the test across cultures and settings (including refugee camps and disaster zones)," the authors wrote.

According to the researchers, their lab in a backpack could be a game changer in the COVID-19 testing space, thanks to its sensitivity and low cost.

"Some of the current LAMP tests available, and sold at airports like Heathrow, can cost around £85," the authors said. "We've shown that the portable lab can be half the cost of such a test. We believe in the beginning the kits can be used in schools as demos for a currently relevant science experiment. Upon validation, we are confident it should be possible to develop commercial tests based on the kits for under £10."

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