Incorporation of Thiol-Modified and Carboxyl-MoS2 Films as Support Layer in Surface Plasmon Resonance Sensing Platform for SARS-CoV-2 Spike Protein Detection

In the event of a severe acute respiratory syndrome–coronavirus-2 (SARS-CoV-2) outbreak, rapid viral detection is crucial for proper patient management. Although the development of surface plasmon resonance (SPR) in optical biosensing for rapid viral detection is growing, gold (Au) as a metallic sensing surface for SPR biosensors exhibits inadequate sensitivity for sensitive viral recognition. Hence, this study attempted to fabricate a rapid and ultrasensitive SPR detection platform using different support layers, such as a self-assembled monolayer (SAM), consisting of 11-Mercaptoundecanoic acid (11-MUA), and 3-Mercaptopropionic acid (3-MPA) in addition to transition-metal dichalcogenide (TMDC) carboxyl-molybdenum disulfide (MoS2-COOH) for the detection of SARS-CoV-2 spike protein (S protein). The sensing surface was characterized using Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM) before and after depositions, followed by SPR measurement testing with variation concentration of SARS-CoV-2 S protein. Performance parameters such as sensitivity, full-width at half-maximum (FWHM), detection accuracy (DA), figure of merit (FoM), quality factor (QF), and limit of detection (LoD) are calculated and compared between 11-MUA/Au/BK7 prism, 3-MPA/Au/BK7 prism, and MoS2-COOH/Au/BK7 prism in the detection of SARS-CoV-2 S protein. Results show the SPR setup with MoS2-COOH single layer exhibited the highest sensitivity (203.55°/RIU) compared to 11-MUA (89.89°/RIU) and 3-MPA (108.90°/RIU). Overall, all three configurations demonstrate good linearity, excellent sensitivity, and LoD in the ng/mL range. The outcome of this study hoped to aid in the future development of a noninvasive, rapid, and ultrasensitive SPR detection platform for viral detection in minimal concentration.