A novel singlet oxygen-based photoelectrochemical diagnostic tool for dengue detection

As arbovirus infections pose a threat to public health, there is a growing demand for rapid, low-cost diagnostic tools that are suitable for point-of-care settings. My research will be focused on detecting the four serotypes of dengue virus (DENV), since it is a leading cause of hospitalization and death in several Asian and Latin American countries1 and therefore classified as one of the 20 neglected tropical diseases by World Health Organization2. More specifically, the innovative platform will combine the low-cost, accurate, rapid, easy-to-use and robust attributes of singlet oxygen (1O2)-based photoelectrochemistry with the integration of plasmonic nanoparticles to enhance sensitivity. First, the target sequence of each serotype will be determined based on the viral RNA amplicons of a clinically validated reverse transcription polymerase chain reaction (RT-PCR) that shows high specificity (no cross-reactivity) and sensitivity. Complementary to these sequences, the capture and detection probes will be designed and optimised, creating a sandwich assay. The capture probe will be linked to a magnetic bead by a biotin-streptavidin bond, ensuring its close position to the electrode surface by placing a magnet underneath, and the detection probes will be labelled with a nanoparticle-photosensitizer complex. Upon illumination by a LED at a specific wavelength, the photosensitizer converts oxygen into singlet oxygen, which in its turn oxidizes a redox reporter. The latter is electrochemically regenerated by applying the correct potential at the electrode surface, resulting in an electrochemical response. I will investigate several ways to couple the photosensitisers to nanoparticles, aiming to exploit the plasmonic effect of noble metal nanoparticles as a way to increase singlet oxygen production and thus also the electrochemical response. In the final stage of the project, the biosensor will be benchmarked against the gold standard RT-PCR and will be validated using patient samples. Here, the required sample preparation will be determined in terms of dilution with buffer and RNA extraction. Currently, an affordable point-of-care technology with similar or better specificity and sensitivity compared to PCR is not available yet. Hence, our technology has the potential to significantly improve patient care and control outbreaks, minimizing the likelihood of an epidemic or even a pandemic.