U-shape functionalized optical fibre sensors for measurement of anaesthetic propofol

Propofol is used widely for intravenous anaesthesia during surgery and sedation in critical care. There is no method currently to assay the concentration of propofol in plasma in real time. The ability to do so would significantly improve patient safety. A novel approach to propofol assay consisting of Beta-Cyclodextrin (β−CD) assisted propofol-imprinting onto TiO2 films deposited on U-shaped optical fibres was used for the measurement of propofol in aqueous solutions. The sensing mechanism is based on the measurement of the refractive index change induced by the removing and binding of the propofol from and to the β−CD/propofol complex embedded onto TiO2 films, respectively. Complexation between host (β−CD) and guest (propofol) was confirmed by nuclear magnetic resonance (NMR) spectroscopy, UV-Vis spectroscopy, and by Attenuated Total Reflectance- Fourier-transform infrared spectroscopy (FTIR). The developed sensors presented Langmuir adsorption in the mM range and the lowest concentration detected was 0.69 μM= 0.12 μg/ml. The approach can be replicated for other compounds in other biomedical applications such as vitamins, hormones, or drugs.