New rapid test kit could detect dengue fever

The Institute of Bioengineering and Nanotechnology (IBN; Singapore) has developed a disposable paper-based device that can detect dengue fever within 20 minutes. The device, details of which were published recently in Lab on a Chip, relies on the detection of dengue-specific antibodies in saliva.

According to Singapore’s National Environment Agency, dengue fever and its more dangerous form dengue hemorrhagic fever, are the most prevalent mosquito-borne viral diseases in the world. There are four known serotypes of the dengue virus and, although the disease is a leading cause of illness and death in tropical and subtropical climates, there is no vaccine or medicine. This means early diagnosis is vital.

Dengue is currently diagnosed via laboratory based blood tests that have the ability to detect the presence of dengue antigens or antibodies. IBN’s device may provide a superior alternative as it is capable of detecting IgG, a dengue-specific antibody found at the onset of secondary infections, directly from saliva in one step. This is beneficial as saliva can be collected easily and painlessly for rapid point-of-care diagnostics.

However, there are problems associated with the use of saliva, which IBN researchers had to overcome. Saliva cannot be applied directly to commercially available test kits as it would lead to sensor nanoparticles sticking haphazardly to the test strip. Moreover, conventional paper-based tests are not equipped to handle the larger sample volume of saliva required. The researchers overcame these challenges by utilizing an innovative stacking flow design.

In the future, IBN’s oral diagnostic kit could be adapted to detect other infectious diseases such as HIV and syphilis. Researchers from IBN are also investigating the use of other fluid samples, such as blood, urine and serum, for rapid high sensitivity test kits.

Sources: Zhang Y, Bai J, Ying JY. A stacking flow immunoassay for the detection of dengue-specific immunoglobulins in salivary fluid. Lab Chip. DOI: 10.1039/C4LC01127A (2015) (Epub ahead of print); Made-in-Singapore rapid test kit detects dengue antibodies from saliva.