Mirrored nano-structures plasmonic biosensor using two-dimensional materials for detection of PSA

Abstract

Surface plasmon resonance methods are a very useful option to provide optical and label-free detection of target biological analytes with many advantages. In this work, a highly sensitive plasmonic biosensor is designed to diagnose prostate cancer using Prostate-Specific Antigen (PSA). To detect PSA, an optical sensor with a mirrored structure based on the Kretschmann configuration is investigated. A numerical calculation finite-difference time-domain (FDTD) method for validation and sensitivity measurement is used. The contact surface of graphene with a sensing layer is very important. Our designed structure benefits from the large surface area and significant field enhancement and this help us to design a biosensor with appropriate performance. The sensitivity of 19.68° per refractive index units (°/RIU) is obtained for mirrored structure while this value was 14.48°/RIU for basic structure. So, the use of a mirror structure increases the sensitivity (nearly 36%) compared to the basic structure. Here, this increase is in compared with the basic structure and the mirrored technique can be applied to other multi-layers structures to further increase their sensitivities.