(INVITED) Stimuli-responsive materials for smart Lab-on-Fiber optrodes

While the Lab-on-Fiber technology goes on with steady step towards the realization of increasingly complex optical nanostructures on optical fiber tips, a new class of materials with unique characteristics in terms of responsivity and functionalities is attracting the attention of the scientific community working in this field. These materials, known as "stimuli-responsive" or "smart", are able to undergo conformational and physiochemical variations if stimulated by the environment. When integrated with optical nanostructures they can strongly improve the light-matter interaction, giving rise to optical devices with enhanced responsivity and with a wide range of functionalities. This review summarizes the recent progresses in the realization of optical devices integrated with stimuli-responsive materials, with a special focus on optical fiber based probes. The multi-responsive character of smart materials, combined with the last advances achieved along Lab-on-Fiber technology roadmap is in fact leading to the effective realization of compact and plug-and-play smart optrodes that can find application especially in life-science field. These devices, in principle, can be opportunely designed to work as bio-chemical sensors, light-triggered loco -regional drug delivery systems, active optical devices and opto-mechanical actuators.