Scientists are creating a pocket-sized device that may rapidly determine varied mosquito-borne ailments


The ongoing COVID-19 pandemic has demonstrated the importance of having tools in place to quickly diagnose viral infectious diseases. In addition to the SARS-CoV-2 virus, which is currently in the spotlight, the Zika, Dengue and Chikungunya viruses have become a major threat to human health in many parts of the world, especially in tropical countries. All three viruses are transmitted by mosquitoes and cause diseases with similar symptoms, making early diagnosis particularly difficult without complex molecular diagnostic equipment.

The Aedes aegypti mosquito can spread various tropical diseases such as dengue fever, zika and chikungunya, which have similar symptoms. The development of simple and inexpensive diagnostic tools is crucial for the early and efficient detection of these diseases.
Image / Gwangju Institute of Science and Technology

To make the diagnosis of these mosquito-borne diseases faster and easier, a team of scientists led by Professor Min-Gon Kim of the Gwangju Institute of Science and Technology in Korea has developed a compact, fully automated and automated team of low-cost tools that detect the presence can identify viruses from a blood serum sample. The device called LAMDA (stands for lab-on-paper for all-in-one molecular diagnostics) by scientists is essentially a mini-laboratory on a strip of paper, vaguely reminiscent of over-the-counter pregnancy tests.

LAMDA performs all steps of a standard nucleic acid test (a molecular diagnostic test), namely sampling, extraction, amplification and detection of the viral target RNA, without the need for external intervention in an intermediate step. To use LAMDA you simply have to put a drop of blood serum and a few drops of distilled water on two pads. The fluids naturally flow horizontally through the paper strip and reach the base of a small vertical stack of layers that extracts all of the RNA from the sample and multiplies the viral RNA of the three diseases present.

The top layer of the vertical stack consists of individual “reaction” patches, each designed to detect one of the three diseases. After the RNA is extracted, it flows into the top layer, where “LAMP (loop-mediated isothermal amplification)” reactions cause the fluorescent indicators on a patch to darken if the target viral RNA is present in the sample.

This allows LAMDA to correctly diagnose any of the three mosquito-borne diseases in less than an hour. Excited about the results published in Elsevier’s Biosensors and Bioelectronics, Prof. Kim notes, “We believe that with minor changes, such as a portable system to keep the reaction temperature at 65 ° C and a means to control the change in fluorescence detectable with a smartphone The proposed all-in-one paper chip can become a portable, inexpensive, user-friendly, sensitive and specific nucleic acid test platform with great potential for point-of-care diagnostics. “

LAMDA could be an excellent option for resource constrained clinics and hospitals, which unfortunately are common in countries most severely affected by mosquito-borne diseases. It could also aid future research in the field of diagnostics for other infectious diseases. “We definitely hope that our approach and our successes with LAMDA will be helpful in promoting research and development of medical diagnostic tools on site,” concludes Prof. Kim.

Perhaps a generation of precise and useful pocket diagnostic tools is on the horizon!

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