Dengue diagnostics: from commercial tests to optical nanosensors.

Dengue virus (DENV) infections are a globally recognised problem, and the development of sensitive, accurate and affordable diagnostic tests is required for better epidemic control and mitigation of mortality and morbidity. With the increasing use of nanoparticles (NPs) in diagnostics, nanoparticle-based optical biosensors emerged as a convenient choice due to their simplicity and potential to satisfy the criteria for an ideal diagnostic test. The optical nanosensors are classified by the colourimetric, surface plasmon resonance (SPR)/localised SPR (LSPR), fluorescence, evanescent wave transmission and surface-enhanced Raman spectroscopy (SERS) characteristics of the NPs. Various NPs, including gold, silver, carbon, iron oxide, and poly(amidoamine) (PAMAM), can be used as signalling materials to enhance test performances. For a critical comparison, target analytes, the basis of the sensor and the performance (limit of detection (LOD), sensitivity, specificity, cross-reactivities) are reviewed. The background information regarding DENV infection progression and the demand for diagnostics at different infection stages allows for a comprehensive understanding of the requirements for useful dengue diagnostic tests. Highlighting the performance strengths and limitations of laboratory-based molecular tests, immunoassays, and rapid diagnostic tests (RDTs) would permit the development of a future strategy in designing a better home-based DENV test.