Current and future opportunities for lateral flow immunoassay strips based on tunable plasmonic properties of gold nanoparticles.

Gold nanoparticles (AuNPs) are widely used in biomedical sensing due to their tunable localized surface plasmon resonance (LSPR) optical properties. The need for traditional sensing methods that do not offer the advantages of timeliness and portability has been addressed by the introduction of lateral flow immunoassay (LFIA) strips, a point-of-care testing (POCT) tool, which offers the advantages of simplicity of handling, visualization, and short detection times. Thus, the combination between LSPR of AuNPs and LFIA strips has evolved to provide a powerful platform capable of ultrasensitive and multiplexed detection of a wide range of target analytes. In recent years, many new types of AuNPs with special morphologic structure and excellent plasmonic optical properties have been developed and used in LFIA. This review focuses on recent advances in novel morphologies and modifications of AuNPs as probes for LFIA strips, highlighting their applications in POCT detection through colorimetric, surface-enhanced Raman scattering, fluorescent, photothermal, and multimodal approaches.