title: Label-free DNA biosensor based on a peptide nucleic acid-functionalized microstructured optical fiber-Bragg grating.
abstract: We describe a novel sensing approach based on a functionalized microstructured optical fiber-Bragg grating for specific DNA target sequences detection. The inner surface of a microstructured fiber, where a Bragg grating was previously inscribed, has been functionalized by covalent linking of a peptide nucleic acid probe targeting a DNA sequence bearing a single point mutation implicated in cystic fibrosis (CF) disease. A solution of an oligonucleotide (ON) corresponding to a tract of the CF gene containing the mutated DNA has been infiltrated inside the fiber capillaries and allowed to hybridize to the fiber surface according to the Watson-Crick pairing. In order to achieve signal amplification, ON-functionalized gold nanoparticles were then infiltrated and used in a sandwich-like assay. Experimental measurements show a clear shift of the reflected high order mode of a Bragg grating for a 100 nM DNA solution, and fluorescence measurements have confirmed the successful hybridization. Several experiments have been carried out on the same fiber using the identical concentration, showing the same modulation trend, suggesting the possibility of the reuse of the sensor. Measurements have also been made using a 100 nM mismatched DNA solution, containing a single nucleotide mutation and corresponding to the wild-type gene, and the results demonstrate the high selectivity of the sensor.
authors.affiliation: University of Parma, Department of Information Engineering, Area Parco delle Scienze 181/A, 43124, Parma, Italy. alessandro.candiani@gmail.com
authors.forename: Alessandro
authors.initials: A
authors.lastname: Candiani
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bertucci
authors.forename: Sara
authors.initials: S
authors.lastname: Giannetti
authors.forename: Maria
authors.initials: M
authors.lastname: Konstantaki
authors.forename: Alex
authors.initials: A
authors.lastname: Manicardi
authors.forename: Stavros
authors.initials: S
authors.lastname: Pissadakis
authors.forename: Annamaria
authors.initials: A
authors.lastname: Cucinotta
authors.forename: Roberto
authors.initials: R
authors.lastname: Corradini
authors.forename: Stefano
authors.initials: S
authors.lastname: Selleri
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D003550:Cystic Fibrosis / Q000235:genetics; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005336:Fiber Optic Technology / Q000295:instrumentation*; D006046:Gold / Q000737:chemistry; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry; D008957:Models, Genetic; D055100:Optical Fibers; D020135:Peptide Nucleic Acids / Q000737:chemistry* / Q000378:metabolism; D017354:Point Mutation; D013057:Spectrum Analysis
chemical_list: D020135:Peptide Nucleic Acids; D006046:Gold; D004247:DNA