title: Iron oxide/gold core/shell nanomagnetic probes and CdS biolabels for amplified electrochemical immunosensing of Salmonella typhimurium.
abstract: There is an imminent need for rapid methods to detect and determine pathogenic bacteria in food products as alternatives to the laborious and time-consuming culture procedures. In this work, an electrochemical immunoassay using iron/gold core/shell nanoparticles (Fe@Au) conjugated with anti-Salmonella antibodies was developed. The chemical synthesis and functionalization of magnetic and gold-coated magnetic nanoparticles is reported. Fe@Au nanoparticles were functionalized with different self-assembled monolayers and characterized using ultraviolet-visible spectrometry, transmission electron microscopy, and voltammetric techniques. The determination of Salmonella typhimurium, on screen-printed carbon electrodes, was performed by square-wave anodic stripping voltammetry through the use of CdS nanocrystals. The calibration curve was established between 1×10(1) and 1×10(6) cells/mL and the limit of detection was 13 cells/mL. The developed method showed that it is possible to determine the bacteria in milk at low concentrations and is suitable for the rapid (less than 1h) and sensitive detection of S. typhimurium in real samples. Therefore, the developed methodology could contribute to the improvement of the quality control of food samples.
authors: REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal; REQUIMTE, Departamento Ciências Químicas, Faculdade Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal.
authors: M
authors: M
authors: Freitas
authors: S
authors: S
authors: Viswanathan
authors: H P A
authors: HP
authors: Nouws
authors: M B P P
authors: MB
authors: Oliveira
authors: C
authors: C
authors: Delerue-Matos
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry; D019187:Cadmium Compounds / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay / Q000379:methods; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry; D008892:Milk / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000302:isolation & purification*; D013440:Sulfides / Q000737:chemistry*
chemical_list: D055910:Antibodies, Immobilized; D019187:Cadmium Compounds; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D013440:Sulfides; C034939:cadmium sulfide; C000499:ferric oxide; D006046:Gold
keywords: Cadmium nanocrystals; Electrochemical immunoassay; Labeled detection; Magnetic nanoparticles; Salmonella typhimurium