A Hybrid Sensing Approach for Coronavirus and Alcohol Detection Based on PCF-SPR Biosensor

A novel PCF-SPR sensor with hybrid sensing capability is presented in this study for detecting both coronavirus and alcohol concentration simultaneously. The sensor utilizes both external and internal sensing approaches to enable simultaneous multi-analyte detection. A thin gold film applied uniformly to the entire external surface as well as the external section of the internal circle that contains the analyte facilitates the surface plasmon resonance (SPR) phenomenon. This hybrid sensor demonstrates excellent performance across the RI range of 1.29 to 1.42 (external, 1.29–1.37; internal, 1.34–1.42). The sensor’s simulation results and performance are analyzed using the finite element method (FEM)–based COMSOL Multiphysics 5.3a. The performance parameters, including wavelength sensitivity (WS), amplitude sensitivity (AS), figure of merit (FOM), and sensor resolution (SR), are assessed for both external and internal sensing modes. The maximum WS and AS are observed to be 13,000 nm/RIU (external) and 5000 nm/RIU (internal), and \(-\) $-$ 1216.45 RIU \(^{-1}\) $_{}^{-1}$ (external) and \(-\) $-$ 85.8465 RIU \(^{-1}\) $_{}^{-1}$ (internal), respectively. The minimum SR is found to be 7.69× \(10^{-6}\) ${10}^{-6}$ RIU (external) and 2.00× \(10^{-5}\) ${10}^{-5}$ RIU (internal), while the highest FOM is noted as 650 RIU \(^{-1}\) $_{}^{-1}$ (external) and 66.667 RIU \(^{-1}\) $_{}^{-1}$ (internal). The hybrid sensor is capable of detecting coronavirus samples at concentrations ranging from 0 to 62.5 nM and determining COVID-positive or negative status using a threshold of 1.953125 nM. It also detects alcohol concentrations in water mixtures ranging from 15 to 70%. With its compact design and high sensitivity, this sensor shows promise for biological analyte sensing.