Rapid and facile colorimetric biosensing of dengue NS1 antigen using gold nanoparticles: potential for point-of-care testing

Abstract

Dengue fever is one of the major global health concerns with increasing incidence and mortality. Early and accurate detection is essential to prevent severe outcomes, especially in resource-limited facilities. Here, we report a rapid, low-cost colorimetric biosensor based on gold nanoparticles (AuNPs) synthesized using ortho-hydroxybenzoic acid, yielding a red wine-coloured solution with a surface plasmon resonance peak at 524 nm. Surface modification with N-[(3-dimethylamino)propyl]-N′-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (2 : 1 ratio) enabled efficient antibody conjugation to NS1 protein monoclonal antibodies. Colorimetric detection with the NS1 antigen provided results within 30 seconds, exhibited excellent linearity (R² = 0.982), and demonstrated limits of detection and quantification of 49.65 ng mL⁻¹ and 165.48 ng mL⁻¹, respectively. This AuNP-based biosensor offers a fast, accurate, and user-friendly platform, potential for point-of-care dengue diagnosis, with nanoparticles remaining stable for up to 28 days.