Biosensor based on microstructured optical fiber Bragg grating for DNA detection

The numerical analysis and the experimental characterization of a novel bio-sensing approach based on a functionalized Penta microstructured optical fiber with a Bragg grating (Penta BG-MOF) for specific DNA target sequences detection have been demonstrated. The inner surface of the fiber has been functionalized using PNA probes, OligoNucleotides mimic that are well suited for specific DNA target sequences detection. The measurements of fluorescence have proved the successful hybridization. After the hybridization has occurred, oligonucleotide functionalized TiO₂ Nano Particles (TiO₂NPs) were infiltrated and used to form a sandwich-like system to achieve signal amplification. The numerical analysis is essential to evaluate physical parameters of the functionalized fiber: the refractive index and the thickness of the layer. The calculated shift of the reflected high order mode Bragg grating has a good agreement with the experimental result.