Adjustable High-Sensitivity Biosensor Utilizing Gold Nanogratings Through the Coupling of Rayleigh Anomaly and LSPR

Localized surface plasmon resonance (LSPR) biosensors find widespread applications in biomedical engineering, environmental monitoring, and food safety owing to their nondestructive and rapid detection capabilities. However, the sensitivity of LSPR sensors is constrained by their broad spectral response. This study introduces a tunable Fano resonance biosensor that leverages the coupling of LSPR and Rayleigh anomaly (RA). The refractive index sensitivity of the sensor was evaluated through measurements of glucose/water solutions at various concentrations, demonstrating a refractive index sensitivity of 685 nm/RIU. Furthermore, the sensor chip functionalized with IgG antibodies, enables label-free detection of IgG antigens and real-time monitoring of biological reaction dynamics. The sensor chip exhibits a detection limit of 40 ng/mL. This straightforward and highly sensitive biosensor chip holds promise for applications in immunoassays, clinical diagnostics, and drug screening in the future.