Plasmon-Based Colorimetric Nanosensor For Fast Detection Of Dengue

Abstract

Dengue is a viral disease, caused by the dengue virus (DENV), transmitted to humans via mosquito bites. It’s estimated that half of the global population is at risk, with between 100 and 400 million infections occurring annually. The disease is prevalent in tropical and sub-tropical regions around the world, particularly in urban and semi-urban areas. While many individuals infected with DENV remain asymptomatic or experience only mild symptoms, the virus can occasionally lead to severe illness and even death. Typical symptoms of dengue include a high fever (40°C), intense headache, eye pain, muscle and joint aches, nausea, vomiting, swollen glands, and a rash. Those who are infected for a second time face a higher risk of severe dengue. Symptoms of severe dengue usually appear after the fever has subsided and include intense abdominal pain, persistent vomiting, rapid breathing, bleeding from the gums or nose, fatigue, restlessness, blood in vomit or stool, extreme thirst, pale and cold skin, and weakness. Hence, early diagnosis is crucial for effective treatment and prevention. In this study, a sensing method was developed using DNA-immobilized plasmonic gold nanoparticles (AuNPs). These AuNPs form heteroduplex structures by specifically binding to the Ribonucleic acid (RNA) genome of the virus, enabling simple, rapid, selective, and highly sensitive detection. Thiolated DNA probes were effectively functionalized onto the surface of AuNPs using a pH-assisted method. The resulting DNA-AuNPs conjugates exhibit stability, making them suitable for downstream colorimetric assays. Thiolated DNA probes were effectively functionalized onto the surface of AuNPs using a pH-assisted method. In the proposed sensing approach, two distinct types of DNA probes are functionalized onto the surface of gold nanoparticles (AuNPs). Upon hybridization with the target RNA, the gaps between the AuNPs decrease, resulting in nanoparticle coupling and subsequent aggregation. Consequently, the AuNPs solution undergoes a color change, turning blue, while samples lacking the target RNA retain their red color. The total analysis time of this strategy is about one hour after the RNA extraction.