Theoretical Design of Highly Sensitive Ag-Ni-Thiol-based Hybrid SPR Biosensor for Viral Detection

In this work, a biosensor under Kretschmann configuration with enhanced sensitivity utilizing thiol on the bimetallic layers of magnetic material nickel (Ni) over silver (Ag) is proposed and analyzed numerically using the Fresnel equation and the Transfer Matrix Method (TMM). Results have shown that such a hybrid configuration with a well-optimized thickness of a bimetallic layer of Ni over Ag and the proper utilization of thiol with fixed thickness can increase the sensitivity substantially higher than the conventional sensor. The minimum reflectivity, FWHM of the Surface Plasmon Resonance (SPR) curve and sensitivity were examined in order to optimize the thickness of metal layers for the fixed thickness of the thiol. It is observed that sensitivity as high as 321º/RIU is obtained for the configuration consisting of 15 nm of Ni over 40 nm thickness of Ag added with a 4 nm thickness of thiol. Such high-sensitivity sensors can be used for protein-protein interaction and virus detection in the field of biosensing applications.