# Direct Detection of Orthoflavivirus via Gold Nanorod Plasmon Resonance

## TL;DR

This paper introduces a new method using gold nanorods to detect Orthoflavivirus in human and mosquito samples with high sensitivity.

## Contribution

The study presents a novel use of functionalized gold nanorods for rapid and sensitive detection of Orthoflavivirus.

## Key findings

- Gold nanorods functionalized with antibodies detected Orthoflavivirus dengue and zikaense with a limit of 100 PFU/mL.
- The method works in diluted human serum and ground-up mosquitoes.
- The approach is promising for improving flavivirus diagnostics and virological surveillance.

## Abstract

Dengue, Zika, yellow fever, chikungunya, and Mayaro arboviruses represent an increasing threat to public health because of the serious infections they cause annually in many countries. Serological diagnosis of these viruses is challenging, making the development of new diagnostic strategies imperative. In this study, we investigated the effectiveness of gold nanorods (GNRs) functionalized with specific anti-dengue and anti-orthoflavivirus antibodies in detecting viral particles. GNRs were created with a length-to-width ratio of up to 5.5, a size of 71.4 ± 6.5 nm, and a light absorption peak at 927 nm, and they were treated with 4 mM polyethyleneimine. These GNRs were attached to a small amount of monoclonal antibodies that target flaviviruses, and the viral particles were detected by measuring the localized surface plasmon resonance using an UV-Vis/NIR spectrometer. The tests found Orthoflavivirus dengue and Orthoflavivirus zikaense in diluted human serum and ground-up mosquitoes, with the lowest detectable amount being 100 PFU/mL. The GNRs described in this study can be used to enhance flavivirus diagnostic tests or to develop new, faster, and more accurate diagnostic techniques. Additionally, the functionalized GNRs presented here are promising for supporting virological surveillance studies in mosquitoes. Our findings highlight a fast and highly sensitive method for detecting Orthoflavivirus in both human and mosquito samples, with a detection limit as low as 100 PFU/mL.