Approaching Gold-Standard Sensitivity in a Portable and Versatile Gold Nanoprisms Thermoplasmonic Platform for...

Plasmonic nanoparticles exhibit unique optical and thermal properties that make them ideal for next-generation diagnostic technologies. Among them, gold nanoprisms (AuNPrs) are especially powerful due to their anisotropic geometry, tunable surface plasmon resonance in the near-infrared (NIR) region, and high photothermal conversion efficiency. These features transform them from passive labels into active nanotransducers capable of amplifying diagnostic signals. Building on these advantages, we developed two AuNPr-based sensing platforms: Thermo Lateral Flow Immunoassay (ThermoLFIA) and Thermo Oligonucleotide-based Lateral Flow Assay (ThermoOLFA). By coupling AuNPrs with thermoresponsive substrates, both systems use localized heat generation to boost analytical sensitivity, enabling visual enhancement far beyond that of conventional gold spheres. ThermoLFIA demonstrated clinically relevant detection of gastrointestinal cancer biomarkers (CEA, CA19-9, VEGF), outperforming standard ELISA tests. In parallel, functionalization of AuNPrs with DNA probes enabled ThermoOLFA to detect SARS-CoV-2 RNA with sensitivity comparable to RT-qPCR, but without amplification steps and within 25 min. This proof-of-concept confirms that plasmonic nanoprisms can drive rapid, portable, and ultrasensitive diagnostics, opening a path toward point-of-care platforms with strong clinical and translational potential.