Cyclodextrin-Based Supramolecular Multilayer Assemblies for the Design of Chemical Optical Sensors Using Tilted Fiber Bragg Gratings

Abstract

In this work, we demonstrate the possibility to use optical fiber incorporating photowritten tilted fiber Bragg gratings (TFBG) as optical detection system for the real time monitoring of interfacial adsorption events. For this purpose, immobilization of cyclodextrin polymers onto the surface of optical fiber was envisioned through the layer-by-layer self-assembly method with the aim of developing sensing layers with well-defined host properties. To verify the feasibility of our strategy, fluorescence microscopy was applied to evidence the effective inclusion of fluorescent molecular, toluene, within the cyclodextrin cavities present onto the optical fiber interface. In a further step, it was demonstrated that the elaboration of the multilayer assembly can be monitored in real time using the TFBG sensor. The host properties of the as-prepared sensing layers were directly applied to develop chemical sensor sensitive to toluene. It was found that the TFBG response was related to the toluene concentration and a linear dependence was observed in the low concentration regime.