Reflection-Based Thin-Core Modal Interferometry Optical Fiber Functionalized With PAA-PBA/PVA for Glucose Detection Under Physiological pH

A phenylboronic-acid-derivatized poly (acrylic acid) (PAA-PBA)/poly(vinyl alcohol) (PVA) functionalized thin-core fiber (TCF) optical sensor is proposed for glucose detection. The unique Michelson-type fiber interferometer sensor was fabricated by splicing a short segment of TCF with a single-mode fiber, where the tip of TCF was melted into a rounded shape. PAA-PBA was synthesized by grafting PBA onto the PAA chain using N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride as coupling reagent. Multilayer films of PAA-PBA and PVA were subsequently functionalized onto the fiber-optic Michelson interferometer structure through layer-by-layer assembly. Experiments showed that the PAA-PBA/PVA functionalized fiber-optic probe exhibits glucose-sensitive behavior under physiological pH. The proposed sensor offers benefits such as simple fabrication, compact size, and glucose selectivity and has potential applications, such as insulin release system, in a biodevice.