Iron oxide/gold core/shell nanomagnetic probes and CdS biolabels for amplified electrochemical immunosensing of Salmonella typhimurium
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- 作者：M. Freitas ; S. Viswanathan ; H.P.A. Nouws ; M.B.P.P. Oliveira ; C. Delerue-Matos
- 关键词：Salmonella typhimurium ; Electrochemical immunoassay ; Magnetic nanoparticles ; Cadmium nanocrystals ; Labeled detection
- 刊名：Biosensors and Bioelectronics
- 出版年：2014
- 出版时间：15 January, 2014
- 年：2014
- 卷：51
- 期：Complete
- 页码：195-200
- 全文大小：822 K
文摘
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¡Á101 and 1¡Á106 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 1 h) 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.