Plasmonic Sensors Exploiting Cellulose Acetate‐Based Biopolymer Optical Fibers

The increasing demand for sustainable and disposable sensing platforms for bio/chemical sensors useful in point‐of‐care tests (POCTs), has spurred the development of biodegradable optical materials capable of replacing conventional fossil‐based materials, such as polymer optical fibers (POFs), in biomedical and environmental applications. In this study, surface plasmon resonance (SPR) sensors using biopolymer optical fibers (Bio‐POFs) made of cellulose acetate (CA) obtained by melt‐extrusion are developed and characterized for the first time. To excite plasmonic phenomena, gold nanolayers were deposited onto CA‐based Bio‐POFs, enabling sensor fabrication in a single production step. Several CA‐based Bio‐POFs were combined with the same gold nanolayers, and the resulting SPR Bio‐POF sensors were characterized using water solutions with different refractive indices. The obtained results demonstrated the capability to change the plasmonic phenomena via the diameter and composition of the CA‐based Bio‐POFs. Therefore, the present study shows that Bio‐POFs can combine sustainability, biodegradability, and custom plasmonic sensing performance, representing a promising route toward next‐generation eco‐friendly disposable optical bio/chemical sensor chips.