CD9 and breast carcinoma: The integration of fiber optic technology with plasmonicbiosensorsis a cutting-edge approach designed to enhance sensor sensitivity.A fiberoptic-integrated surface plasmon resonance (FO-SPR) biosensorwas created for the purpose of detecting breast cancer-specific EVsdirectly from blood plasma.87 To detectSK-BR-3 EVs, FO-SPR probes were functionalized with anti-HER2/biotinylatedanti-CD9 (Banti CD9) antibodies to produce a sandwich bioassay(Figure 6A).