Synthesis of cobalt ferrite core/metallic shell nanoparticles for the development of a specific PNA/DNA biosensor.
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.
Pita
Marcos
M
Instituto de Catálisis y Petroleoquímica, CSIC, C/Marie Curie 2, 28049 Cantoblanco, Madrid, Spain. marcospita@icp.csic.es
Abad
José María
JM
Vaz-Dominguez
Cristina
C
Briones
Carlos
C
Mateo-Martí
Eva
E
Martín-Gago
José Angel
JA
Morales
Maria del Puerto
Mdel P
Fernández
Víctor M
VM
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
D000588:Amines; D005290:Ferric Compounds; D020135:Peptide Nucleic Acids; D013438:Sulfhydryl Compounds; C001215:ferrite; D003035:Cobalt; D006046:Gold; D004247:DNA