Gold nanocubes etching enhanced light scattering immunoassay for highly sensitive detection of Staphylococcus aureus...

An innovative light scattering immunoassay was developed using an AuNPs etching strategy. Three types of anisotropic gold nanoparticles, including gold nanocubes, nanorods, and nanoflowers with distinct morphologies, were utilized to investigate how these morphological differences affect the sensitivity of light scattering signal transduction. Based on theoretical insights into light scattering and electromagnetic fields, gold nanocubes were identified as the optimal probes for enhancing light scattering signal transduction and were employed to construct an immunoassay for detecting staphylococcal enterotoxin A (SEA). The developed immunoassay achieved ultrahigh sensitivity for SEA detection in milk samples, with a detection limit of 10.39 pg mL^-1, which is 190 times lower than that of conventional ELISA. The proposed immunoassay was validated across ten food samples, demonstrating high accuracy and robustness. Given these promising results, we believe this method has significant potential for screening trace levels of SEA in food products.