Preliminary Study on Development of D-Shape Polymer Optical Fiber-Based SPR Sensor for Biochemical Applications

Surface Plasmon Resonance (SPR)-based sensing has gained increasing popularity in diverse biochemical contexts, particularly in detecting biomolecular interactions owing to its real-time detection capability and well-established high sensitivity for label-free biomolecule detection. This has led to a rising interest in advancing SPR sensing for swift testing at the point of care. Nevertheless, commercial SPR sensors are inappropriate due to their considerable dimensions, lack of mobility, and elevated expenses. Conversely, utilizing fiber optic-based SPR sensing presents an opportunity to create compact and easily transportable SPR instruments ideally suited for convenient, rapid, and economically viable point-of-care testing. Within this investigation, the researcher conducted an initial exploration to construct an SPR sensor employing polymer optical fiber (POF). In contrast, the refinement of fabrication methods and the deposition of thin gold film thickness were fine-tuned to assess the optical characteristics of the POF-based SPR sensor’s reaction towards alterations in refractive index by utilizing diverse concentrations of glycerin solutions. Out of the array of POF-based SPR sensors manufactured, the most effective sensor displayed a sensitivity measure of $4.585 \pm 0.489$ accompanied by an R-squared coefficient of 0.936, a Limit of Detection (LoD) of 0.31 mM, a stability rate of 63.5%, and a penetration depth of 77.7 nm. These outcomes underscore the capability of the developed POF-based SPR sensor to produce surface plasmon resonance and provide a reliable SPR output in identifying fluctuations in glycerin concentration within the D-shaped sensing component. This investigation sets the stage for developing portable and compact SPR sensors for point-of-care implementations.