The Institute of Bioengineering and Nanotechnology (IBN) of A*STAR in Singapore has developed a paper-based disposable device that will allow dengue-specific antibodies to be detected easily from saliva within 20 minutes. This device is currently undergoing further development for commercialization.
IBN Executive Director Professor Jackie Y. Ying shared, “Our rapid diagnostic kit can detect a key dengue antibody from saliva that is present in early-stage secondary infection. The ability to differentiate between primary and secondary dengue infections makes it a valuable early diagnosis tool that would help to ensure timely treatment and proper care of patients.”
Currently, dengue infection is diagnosed in the laboratory by testing the patient’s blood sample for the presence of dengue antigens or antibodies. IBN’s device, on the other hand, is capable of detecting IgG, a dengue-specific antibody found at the onset of secondary infections, directly from saliva in one step.
Unlike blood samples, saliva can be collected easily and painlessly for rapid point-of care diagnostics. However, unlike other body fluids, it cannot be applied directly to commercially available test kits as it would cause the sensor nanoparticles to stick haphazardly to the test strip. In addition, conventional paper-based tests are not designed to handle the larger sample volume of saliva required.
As described in the journal Lab on a Chip, the IBN researchers used an innovative stacking flow design to overcome key challenges faced by existing lateral flow designs, such as those used in pregnancy test kits. In IBN’s device, different flow paths are created for samples and reagents through a multiple stacked system. This allows the saliva sample to flow separately through a fiber glass matrix, which removes the substances that would interfere with the nanoparticlebased sensing system before it mixes with the sensor nanoparticles.
IBN’s device configuration also helps to regulate the flow in the test strip, generating uniform test lines for more accurate results. By simplifying the diagnostic procedure, the researchers hope to make the device as easy to use as over-the-counter pregnancy or fertility test kits. IBN’s oral test kit may be adapted to detect other infectious diseases. The IBN researchers are also investigating the use of other common fluid samples, such as blood, urine and serum for rapid, high sensitivity test kits.