Extreme sensitivity biosensing platform based on Fano resonance and graphene oxide

Improving the sensitivity of surface plasmon resonance (SPR) sensors is a crucial field of research, as it enables the detection of lower concentrations of analytes and smaller biomolecular interactions. This study developed a novel Fano resonance (FR) sensor with exceptional sensitivity and figure of merit ( FOM ) by combining graphene oxide (GO) with a plasmonic silver film-polydimethylsiloxane (PDMS) hybrid nanostructure. The results demonstrated that the FR-GO sensor achieved an average refractive index (RI) sensitivity of 33.6 μm/RIU, representing a 20.53 % improvement over the FR sensor (27.9 μm/RIU). Additionally, the FOM increased by 36.25 %, reaching a maximum of 2383.82 RUI −1 , which was two orders of magnitude higher than traditional SPR sensors. To evaluate its practical application, the sensor was used to detect carcinoembryonic antigen (CEA), a tumor biomarker. The proposed sensor exhibited a measurement sensitivity of 5.2 nm/(ng/ml) and a limit of detection ( LOD ) of 63.5 pg/ml. Furthermore, the method demonstrated good selectivity, reproducibility, and stability. The enhanced sensitivity and FOM of this sensor design have the potential to advance early disease detection and biomolecular interaction studies.