'Origami' diagnostic device for remote malaria detection
Researchers have revealed how origami-style folded paper, prepared with a printer and a hotplate, has detected malaria with 98% sensitivity in infected participants in Uganda, in a breakthrough that brings affordable, reliable field tests to remote parts of the developing world.
Malaria is one of the world’s leading causes of illness and death, affecting more than 219 million people in 90 countries around the globe and killing 435,000 people in 2017 alone. In order to prevent the spread of the disease, it must be accurately diagnosed in people who are infected but who do not display any symptoms; but current tests, which rely on polymerase chain reaction (PCR), can only be carried out under laboratory conditions, making them unsuitable for use in remote locations.
Researchers from the University of Glasgow, in partnership with Shanghai Jiao Tong University and the Ministry of Health in Uganda, have now developed a diagnostic approach that uses paper to prepare patient samples for a detection process known as loop-mediated isothermal amplification (LAMP), which is more portable and better suited to use in the field. The origami platform uses a commercially available printer to coat the paper in patterns made from water-resistant wax, which is then melted on a hotplate, bonding the wax to the paper.
A blood sample taken from a patient via finger prick is placed in a channel in the wax, then the paper is folded, directing the sample into a narrow channel and then three small chambers. The LAMP machine uses these to test the samples’ DNA for evidence of Plasmodium falciparum, the mosquito-borne parasitic species which causes malaria. The test can be completed on site in less than 50 min and has been described in the journal PNAS.
“We tested our approach with volunteers from two primary schools in the Mayuge and Apac districts in Uganda,” said the University of Glasgow’s Professor Jonathan Cooper, lead author on the paper.
“We took samples from 67 schoolchildren, under strict ethical approval, and ran diagnostic tests in the field using optical microscopy techniques, the gold standard method in these low-resource settings, a commercial rapid diagnostic procedure known as a lateral flow test and our LAMP approach. We also carried out PCR back in Glasgow, on samples collected in the field.
“Our diagnostic approach correctly diagnosed malaria in 98% of the infected samples we tested — markedly more sensitive than both the microscopy and lateral flow tests, which delivered 86% and 83% respectively.
“It’s a very encouraging result which suggests that our paper-based LAMP diagnostics could help deliver better, faster, more effective testing for malaria infections in areas which are currently underserved by available diagnostic techniques.”
Glasgow’s Dr Julien Reboud, who played a key role in developing the new diagnostic technique, added, “These are challenging environments for any test of this type, with no access to the kinds of refrigeration, special equipment and training that more traditional diagnostic procedures require, so it’s very encouraging that the diagnostic techniques we’ve developed have proven to be so sensitive and reliable.
“It’s vital that new forms of diagnosis reach the people who need them, and we’re committed to developing our approach to paper-based LAMP diagnostics further after this encouraging study.”
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