Zika and Dengue are mosquito-borne diseases that are currently a major global threat. Both diseases cause similar initial symptoms (fever or headache) but possess drastically different outcomes. Dengue can result in life-threatening hemorrhagic fever, whereas zika is linked to microcephaly in newborns and other neurological manifestations. Both viruses can co-circulate geographically, as they share the same transmission vector, which implies that the two diseases coexist in epidemic areas and a patient can have both of them at the same time. This overlap in clinical presentations and geographic co-localization make it difficult to distinguish between the two. Therefore, there is an urgent need to develop point-of-care (POC) devices (portable, low-cost and user-friendly) that can differentiate the two diseases not only for patient treatment and quarantine but also for disease surveillance and rapid response efforts.<br/>Paper-based sandwich immunoassays such as lateral flow assays (LFA) are attractive as POC solutions as they have the potential for wider deployability than lab-based assays such as PCR. However, the low sensitivity of these assays imposes limitations on their ability to detect low biomarker levels, which is the case for Zika infections, co-infections with other viruses, and also for early diagnosis of any disease.<br/>Here, we exploit the high sensitivity of Surface-Enhanced Raman spectroscopy (SERS) in a multiplexed assay that can distinguish between zika and dengue non-structural protein (NS1) biomarkers. SERS-encoded gold nanoparticles (GNP) were conjugated to specific antibodies for NS1 to distinguish between ZIKV and DENV without cross-reactivity in a dipstick immunoassay.<br/>Two different Raman reporters, BPE and 4-MBA, have been used to detect and differentiate between both viruses in a multiplex assay by measuring the SERS signal on the test line of the LFA strip. Using GNPs, the Raman signal of a specific reporter adsorbed on the GNP surface can be enhanced by several orders of magnitude, due to the higher intensity of the electric field on the gold surface, leading to what is called SERS. The enhancement of the synthesized GNPs allowed the detection of very low concentrations of the virus with a limit of detection of 0.79 ng/ml for ZIKV and 10 ng/ml DENV, 15 and 7-fold lower than that of colorimetric LFA.

Design of SERS nanotags for the multiplexed detection of dengue and zika in lateral flow assay

256th National Meeting (2018)

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