PNA-modified photonic crystal fibers for DNA detection

Biophotonics represents a very attractive and promising field of interest for biosensing applications [1]. Hybrid optical fibers bearing specific probes for DNA detection are advanced tools in which the sensing element can be integrated in a microfluidic device for the generation of optical signals [2, 3]. In particular, Photonic Crystal Fibers (PCFs) have the unique feature of presenting a cross-section defined by air-hole arrays, allowing to perform internal functionalization [4, 5]. In this work, the feasibility of a novel specific DNA sensing platform, based on the use of PCFs bearing a Bragg grating, is described, together with a strategy for enhancement of the optical signal based on the use of gold nanoparticles (Au NPs). Very specific Peptide Nucleic Acid (PNA) probes, Oligonucleotide (ON) mimics that are well suited for specific DNA target sequences detection, have been used due to their highly favourable properties in DNA hybridization and chemical and biological stability.