In this work the inner surface of a microstructured optical fiber, where a Bragg grating was previously inscribed, has
been functionalized using peptide nucleic acid probe targeting a DNA sequence of the cystic fibrosis disease. The
solution of DNA molecules, matched with the PNA probes, has been infiltrated inside the fiber capillaries and
hybridization has been realized according to the Watson - Crick Model. In order to achieve signal amplification,
oligonucleotide-functionalized gold nanoparticles were then infiltrated and used to form a sandwich-like system.
Experimental measurements show a clear wavelength shift of the reflected high order mode for a 100 nM DNA solution.
Several experiments have been carried out on the same fiber using the identical concentration, showing the same
modulation and proving a good reproducibility of the results, suggesting the possibility of the reuse of the sensor.
Measurements have been also made using a 100 nM mis-matched DNA solution, containing a single nucleotide
polymorphism, demonstrating the high selectivity of the sensor.