Gold Nanoparticle-Based Breath Test Device for Rapid Detection of Infections

Respiratory tract infections (RTIs), including COVID-19, influenza, and respiratory syncytial virus infections represent a significant global health burden. Traditional diagnostic methods, such as polymerase chain reaction (PCR) and rapid antigen tests, have limitations in terms of invasiveness, time consumption, and sensitivity. To address these challenges, we developed a gold nanoparticle-based breath test device that enables rapid, non-invasive detection of infections at the point-of-care (POC). The device measures the colorimetric properties of gold nanoparticles (GNPs), which change upon aggregation when exposed to specific antigens filtered from exhaled breath. The system integrates sampling and analysis in a portable unit, providing results within 30 seconds. In this proof-of-concept, we demonstrate the detection of SARS-CoV-2 antigens through shifts in the localized surface plasmon resonance (LSPR) of GNPs. Initial tests using NaCl-induced GNP aggregation validate the device's functionality. This innovative approach shows promising first results for rapid, user-friendly infection diagnostics from exhaled breath, with potential applications in mass screening and POC testing. Further optimization is needed to enhance sensitivity and reliability