In this article, a high-accuracy novel optical biosensor consisting of a structurally chiral medium (SCM) with 4 ̅2m point group symmetry and a silver metallic defect layer under the Sarid configuration as a theoretical and computational study has been investigated. We used incident light with p polarization and used the 4 × 4 transfer matrix method for absorption spectrum calculations. Surface plasmon polaritons (SPP) modes at the interface between a metallic layer and SCM have also been investigated. One of the advantages of using the SCM in this configuration is that it allows us to have several plasmonic and waveguide modes. We have also determined the difference between plasmonic modes and waveguide modes. This configuration creates an open assay interface for real-time detection of the interaction with extremely high sensitivity. The resonance angles observed in the absorption spectrum are very sensitive to changes in the fluid placed on top of the sensor and this sensor has a very high-quality factor that distinguishes it from other sensors. The effect of the tilt angle of the SCM has also been investigated. These combinations make the proposed designed sensor unique for performing label-free bioassays in the detection of cancer cells. The basis of this research is to detect cancer cells, which the designed sensor can detect with high sensitivity factors.
