title: Synthesis of cobalt ferrite core/metallic shell nanoparticles for the development of a specific PNA/DNA biosensor.
abstract: Controlled synthesis of cobalt ferrite superparamagnetic nanoparticles covered with a gold shell has been achieved by an affinity and trap strategy. Magnetic nanoparticles are functionalized with a mixture of amino and thiol groups that facilitate the electrostatic attraction and further chemisorption of gold nanoparticles, respectively. Using these nanoparticles as seeds, a complete coating shell is achieved by gold salt-iterative reduction leading to monodisperse water-soluble gold-covered magnetic nanoparticles, with an average diameter ranging from 21 to 29 nm. These constitute a versatile platform for immobilization of biomolecules via thiol chemistry, which is exemplified by the immobilization of peptide nucleic acid (PNA) oligomers that specifically hybridize with complementary DNA molecules in solution. Hybridation with DNA probes has been measured using Rhodamine 6G fluorescence marker and the detection of a single nucleotide mutation has been achieved. These results suggest the PNA-nanoparticles application as a biosensor for DNA genotyping avoiding commonly time-consuming procedures employed.
authors.affiliation: Instituto de Catálisis y Petroleoquímica, CSIC, C/Marie Curie 2, 28049 Cantoblanco, Madrid, Spain. marcospita@icp.csic.es
authors.forename: Marcos
authors.initials: M
authors.lastname: Pita
authors.forename: José María
authors.initials: JM
authors.lastname: Abad
authors.forename: Cristina
authors.initials: C
authors.lastname: Vaz-Dominguez
authors.forename: Carlos
authors.initials: C
authors.lastname: Briones
authors.forename: Eva
authors.initials: E
authors.lastname: Mateo-Martí
authors.forename: José Angel
authors.initials: JA
authors.lastname: Martín-Gago
authors.forename: Maria del Puerto
authors.initials: Mdel P
authors.lastname: Morales
authors.forename: Víctor M
authors.initials: VM
authors.lastname: Fernández
mesh_terms: D000588:Amines / Q000737:chemistry; D001483:Base Sequence; D015374:Biosensing Techniques; D003035:Cobalt; D004247:DNA / Q000032:analysis* / Q000235:genetics; D005290:Ferric Compounds; D006046:Gold; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D020135:Peptide Nucleic Acids / Q000032:analysis* / Q000235:genetics; D013050:Spectrometry, Fluorescence; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000588:Amines; D005290:Ferric Compounds; D020135:Peptide Nucleic Acids; D013438:Sulfhydryl Compounds; C001215:ferrite; D003035:Cobalt; D006046:Gold; D004247:DNA