Ricerc@Sapienza

The combination of fiber-optic–based platforms for biosensing with nanotechnologies is opening up the chance for the
development of in situ, portable, lightweight, versatile, reliable and high-performance optical sensing devices. The route
consists of the generation of lossy mode resonances (LMRs) by means of the deposition of nm-thick absorbing metaloxide
films on special geometric-modified fibers. This allows measuring precisely and accurately the changes in surface
refractive index due to the binding interaction between a biological recognition element and the analyte, with very high
sensitivity compared to other optical technology platforms, such as fiber gratings or surface plasmon resonance. The
proposed methodology, mixed with the use of specialty fiber structures such as D-shaped fibers, allows improving the
light-matter interaction in a strong way. The shift of the LMR has been used to monitor in real-time the biomolecule
interactions thanks to a conventional wavelength-interrogation system and an ad-hoc developed microfluidics. A big leap
in performance has been attained by detecting femtomolar concentrations in real samples of human serum. The biosensor
regeneration has been also studied by using a solution of sodium dodecyl sulphate (SDS), proving the device reusability.
Therefore, this technology possibly represents a paradigm shift in the development of a simple, high-specificity and
label-free biosensing platform, which can be applied to speed up diagnostic healthcare processes of different diseases
toward an early diagnostic and personalized treatment system.