Plasmonic optical fiber meta-tip for cancer biomarkers detection.

Sensors based on Lab-On-Tip (LOT) technology, where suitably designed sensitive nanostructures are integrated on the end-face of an optical fiber, are of strategic importance especially in medicine and clinical diagnostics, where miniaturization and portability are key characteristics. LOT biosensors developed in the past are mostly based on plasmonic nanostructures and exploit a label-free detection paradigm. This detection scheme, however, has some limitations when the target molecules are small or when the specific application requires very low detection limits. To overcome such limitation, we proposed in 2017 the integration of plasmonic Metasurfaces (MSs) on the tip of the optical fiber (Optical Fiber Meta-Tip, OFMT). For their extraordinary properties, MSs are able to enhance the light-matter interaction on the fiber tip, thus sensibly improving the performance of LOT biosensors. Here we present our results on OFMTs, showing past, present and future work. In particular, we report for the first time on the remarkable capabilities of plasmonic OFMTs to perform label-free detection of cancer biomarkers with improved performances with respect to state-of-the-art LOT sensors.