Green LSPR Sensors Based on Thin Bacterial Cellulose Waveguides for Disposable Biosensor Implementation

Abstract

Nowadays there is an increasing request to realize green, eco-friendly, and biodegradable electronic devices for biosensor implementation. In this context, we have conceived and realized a green sensor based on localized surface plasmon resonance (LSPR) phenomenon in a thin-slab waveguide of bacterial cellulose (BC). These LSPR sensors can be obtained simply by gold sputtering on the slab BC waveguides. The performances have been studied investigating the presence of ionic liquids (ILs) inside and in absence of ILs with various thicknesses of the BC substrate. Depending of the thickness of the BC layer, the ILs effect on the LSPR can be constructive or destructive. In this work, we present a study of the sensor performances, in terms of bulk sensitivity and resolution by changing the aforementioned parameters. Analyses in terms of BC geometry are pursued in order to improve the interaction between the light and the LSPR phenomenon. The experimental setup used for this kind of extrinsic optical fiber LSPR sensor is based on two optical fibers used to connect a white light source and a spectrometer with the green LSPR sensor chip. Results evince the suitability of the proposed approach in order to realize sensors and biosensors with several intriguing properties and features. In fact, these LSPR platforms could be used to realize disposable biosensors, when a specific bioreceptor is covalently bonded to the gold.