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Journal of Nanomaterials
Volume 2015, Article ID 527126, 9 pages
Research Article

Colorimetric Detection System for Salmonella typhimurium Based on Peroxidase-Like Activity of Magnetic Nanoparticles with DNA Aptamers

1Department of Chemistry, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Republic of Korea
2Department of BioNano Technology, Gachon University, 1342 Seongnamdae-ro, Sujeoung-gu, Seongnam-si, Gyeonggi-do 461-701, Republic of Korea

Received 2 June 2015; Revised 16 July 2015; Accepted 21 July 2015

Academic Editor: Wei Chen

Copyright © 2015 Ji Young Park et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Recently, much attention has been devoted to food-related health issues. In particular, food-poisoning bacteria are becoming a serious threat to human health. So far, techniques used to detect these bacteria are time-consuming and laborious. To overcome these challenges, a biosensor with a simple platform was developed to detect Salmonella typhimurium. The colorimetric strategy is attractive because it enables simple and rapid sensing with the naked eyes. We used magnetic nanoparticles (MNPs), specific aptamers, and a colorimetric substrate, 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. Because MNPs display enzyme-like activities, they can undergo color changes with the help of a colorimetric substrate. In this system, MNPs were first incubated with aptamers that specifically interact with the Salmonella species, reducing the peroxidase activity of the MNPs via DNA-mediated shielding of catalytic activity. After the addition of Salmonella cells to the solution, specific aptamers on the MNPs interact with the Salmonella, consequently enhancing the peroxidase activity of the MNPs. Considering their low cost, easy separation, and stable activity, MNPs could be applied to various detection systems.