Optical fibre sensors based on long period gratings (LPG) modified with functional coatings that can change their optical properties in response to the presence of the particular analyte have attracted much research attention. Ultimately such sensors have the capability to become highly sensitive and selective bio- and chemical sensors. In addition to the advantages of all optical fibre sensors such as miniature size, immunity to electromagnetic interference and low power consumption, LPGs offer wavelengths encoded information which eliminates the need for a reference and are mechanically robust which makes them attractive for practical application. One of the key components in LPG bio- and chemical optical fibre sensors is a capture layer that provides chemical selectivity to the target analyte. In this work, an overview of the different LPG bio- and chemical optical fibre sensors functionalised with various capture layers such as mesoporous thin films, molecularly imprinted polymers (MIPs) and metal-organic frameworks (MOFs) will be presented. Particular focus will be given to potential applications of the novel optical fibre LPG sensors in healthcare with examples of measuring biomarkers (protein M-immunoglobulin) and drug delivery (anaesthetics) in intensive care.
