Fe 3 O 4 @Au Core-Shell Magnetic Nanoparticles for the Rapid Analysis of E. coli O157:H7 in an Electrochemical Immunoassay

• Published in: Biosensors (Basel) Vol. 13; no. 5
• Main Authors: Bazsefidpar, Shayesteh, Freitas, Maria, Pereira, Clara R, Gutiérrez, Gemma, Serrano-Pertierra, Esther, Nouws, Henri P A, Matos, María, Delerue-Matos, Cristina, Blanco-López, María Carmen
• Format: Journal Article
• Language: English
• Published: Switzerland 22.05.2023
• Subjects: Carbon; Escherichia coli O157; Humans; Immunoassay - methods; Magnetite Nanoparticles - chemistry; pathogenic bacteria; amperometric biosensor; SPCE; immunomagnetic assay; magnetic core–shell nanoparticles
• ISSN: 2079-6374

( ) O157:H7 is a pathogenic bacterium that causes serious toxic effects in the human gastrointestinal tract. In this paper, a method for its effective analytical control in a milk sample was developed. To perform rapid (1 h) and accurate analysis, monodisperse Fe O @Au magnetic nanoparticles were synthesized and used in an electrochemical sandwich-type magnetic immunoassay. Screen-printed carbon electrodes (SPCE) were used as transducers, and electrochemical detection was performed by chronoamperometry using a secondary horseradish peroxidase-labeled antibody and 3,3',5,5'-tetramethylbenzidine. This magnetic assay was used to determine the O157:H7 strain in the linear range from 20 to 2 × 10 CFU/mL, with a limit of detection of 20 CFU/mL. The selectivity of the assay was tested using p60 protein, and the applicability of the assay was assessed by analyzing a commercial milk sample, demonstrating the usefulness of the synthesized nanoparticles in the developed magnetic immunoassay.