Lateral flow immunoassay using plasmonic scattering
Bobin Lee, Byungho Park, Daeun Kim, Chaewon Jung, Jun Hyeok Park, Ji‐Ho Park, Y. Lee, Myung‐Geun Shin, Min‐Gon Kim, Nan Ei Yu, Joon Heon Kim, Kihyeun Kim
Abstract
The lateral flow immunoassay (LFIA) is one of the most successful sensing platforms for real-world point-of-care (POC) testing. However, achieving PCR-level sensitivity without compromising the inherent advantages of LFIA, such as rapid and robust operation, affordability, and naked-eye detection, has remained a primary challenge. In this study, a plasmonic scattering-utilising LFIA was proposed, created by transparentising a nitrocellulose membrane and placing a light-absorbing backing card under the membrane. This LFIA minimised the background signal from its matrix, leading to substantially enhanced sensitivity and enabling naked-eye detection of the plasmonic scattering signal from gold nanoparticles without optics. Our plasmonic scattering-utilising LFIA showed an approximately 2600–4400 times higher detection limit compared with that of commercial LFIAs in influenza A assays. In addition, it exhibited 90% sensitivity in clinical validation, approaching PCR-level sensitivity, while commercial LFIAs showed 23–30% sensitivity. The plasmonic scattering-utilising LFIA plays a ground-breaking role in POC diagnostics and significantly boosts follow-up research. Lateral flow immunoassays (LFIA) are commonly used for point-of-care testing, but have limited sensitivity. Here, the authors present a LFIA based on plasmonic scattering and a light-absorbing background, resulting in significantly enhanced sensitivity.