title: Fe2O3@Au core/shell nanoparticle-based electrochemical DNA biosensor for Escherichia coli detection.
abstract: A Fe(2)O(3)@Au core/shell nanoparticle-based electrochemical DNA biosensor was developed for the amperometric detection of Escherichia coli (E. coli). Magnetic Fe(2)O(3)@Au nanoparticles were prepared by reducing HAuCl(4) on the surfaces of Fe(2)O(3) nanoparticles. This DNA biosensor is based on a sandwich detection strategy, which involves capture probe immobilized on magnetic nanoparticles (MNPs), target and reporter probe labeled with horseradish peroxidase (HRP). Once magnetic field was added, these sandwich complexes were magnetically separated and HRP confined at the surfaces of MNPs could catalyze the enzyme substrate and generate electrochemical signals. The biosensor could detect the concentrations upper than 0.01 pM DNA target and upper than 500 cfu/mL of E. coli without any nucleic acid amplification steps. The detection limit could be lowered to 5 cfu/mL of E. coli after 4.0 h of incubation.
authors.affiliation: Department of Chemistry, East China Normal University, Shanghai 200062, PR China.
authors.forename: Kang
authors.initials: K
authors.lastname: Li
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Lai
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Litong
authors.initials: L
authors.lastname: Jin
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques; D015169:Colony Count, Microbial; D004247:DNA / Q000737:chemistry*; D015342:DNA Probes; D004563:Electrochemistry / Q000295:instrumentation*; D004800:Enzymes, Immobilized / Q000737:chemistry; D004926:Escherichia coli / Q000302:isolation & purification*; D005290:Ferric Compounds / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry; D057230:Limit of Detection; D053768:Metal Nanoparticles
chemical_list: D015342:DNA Probes; D004800:Enzymes, Immobilized; D005290:Ferric Compounds; C000499:ferric oxide; D004247:DNA; D006735:Horseradish Peroxidase