D-Shaped PCF Based SPR Sensor for Cortisol Detection

This study suggested a Surface plasmon resonance (SPR) using a D-shaped photonic crystal fiber (PCF) sensor to measure the cortisol Concentration in human saliva and monitor stress levels in real-time. To examine the impact of SPR, D-shaped PCF was coated with a thin layer of gold, to facilitate cortisol binding for experimental verification, the gold coating must be functionalized using cysteamine and an anti-cortisol antibody. Using the Finite Element Method (FEM), the suggested sensor is designed and subjected to numerical analysis using COMSOL Multiphysics. The findings demonstrate that by employing the amplitude interrogation approach, the sensing qualities are significantly improved wavelength sensitivity (W.S) of 5000 (nm/RIU), peak amplitude sensitivity (A.S) of 15349.81 RIU<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and resolution reaches up to 806.4×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> RIU<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>. The suggested sensor can detect cortisol levels between 1.2 and 10 ng/ml.