Self-Assembly of Nanogold Triplets on Trimeric Viral Proteins for Infectious Disease Diagnosis

Timely and accurate diagnostics for infectious diseases are essential in preventing their worldwide spread. Though rapid diagnostic tests are favored for their speed, cost-effectiveness, and ease of use, most tests compromise sensitivity, which risks false-negative results. Here, we present the self-assembly of nanogold triplets on trimeric viral surface proteins for a sensitive colorimetric assay to identify viruses. Gold triplets were self-assembled on the viral trimeric surface proteins using ultrasmall gold nanoparticles. We observed a significant wavelength shift of 70 nm, enabling straightforward naked-eye detection through gold triplets that act as catalysts for producing nanoplasmonic viruses. We established the detection limit of 3 × 10⁵ copies/ml using an effective colorimetric assay for detecting SARS-CoV-2. The self-assembly of gold triplets on trimeric viral surface proteins provides a reliable approach to the accurate and sensitive detection of viruses.